Clean Air Act (United States)

The Clean Air Act is a United States federal law designed to control air pollution on a national level . It is one of the United States ' first and most influential modern environmental laws , and one of the most comprehensive air quality laws in the world . As with many other major U.S. federal environmental statutes , it is administered by the U.S. Environmental Protection Agency ( EPA ) , in coordination with state , local , and tribal governments . Its implementing regulations are codified at 40 C.F.R. Subchapter C , Parts 50-97 .   The 1955 Air Pollution Control Act was the first U.S federal legislation that pertained to air pollution ; it also provided funds for federal government research of air pollution . The first federal legislation to actually pertain to `` controlling '' air pollution was the Clean Air Act of 1963 . The 1963 act accomplished this by establishing a federal program within the U.S. Public Health Service and authorizing research into techniques for monitoring and controlling air pollution . In 1967 , the Air Quality Act enabled the federal government to increase its activities to investigate enforcing interstate air pollution transport , and , for the first time , to perform far-reaching ambient monitoring studies and stationary source inspections . The 1967 act also authorized expanded studies of air pollutant emission inventories , ambient monitoring techniques , and control techniques .   Major amendments to the law , requiring regulatory controls for air pollution , passed in 1970 , 1977 and 1990 .   The 1970 amendments greatly expanded the federal mandate , requiring comprehensive federal and state regulations for both stationary ( industrial ) pollution sources and mobile sources . It also significantly expanded federal enforcement . Also , the Environmental Protection Agency was established on December 2 , 1970 for the purpose of consolidating pertinent federal research , monitoring , standard-setting and enforcement activities into one agency that ensures environmental protection .   The 1990 amendments addressed acid rain , ozone depletion , and toxic air pollution , established a national permits program for stationary sources , and increased enforcement authority . The amendments also established new auto gasoline reformulation requirements , set Reid vapor pressure ( RVP ) standards to control evaporative emissions from gasoline , and mandated new gasoline formulations sold from May to September in many states .   Reviewing his tenure as EPA Administrator under President George H. Bush , William K. Reilly characterized passage of the 1990 Clean Air Act as his most notable accomplishment .   The Clean Air Act was the first major environmental law in the United States to include a provision for citizen suits . Numerous state and local governments have enacted similar legislation , either implementing federal programs or filling in locally important gaps in federal programs .


Clean Power Plan

The Clean Power Plan is an Obama administration policy aimed at combating anthropogenic climate change ( global warming ) that was first proposed by the Environmental Protection Agency in June 2014 . It is widely expected to be eliminated under President Donald Trump , who signed an executive order on March 28 , 2017 mandating the EPA to review the plan .   The final version of the plan was unveiled by President Obama on August 3 , 2015 . The 460-page rule ( RIN 2060 -- AR33 ) titled `` Carbon Pollution Emission Guidelines for Existing Stationary Sources :  Electric Utility Generating Units '' was published in the Federal Register on October 23 , 2015 . The Obama administration designed the plan to lower the carbon dioxide emitted by power generators .


Climate

Climate is the statistics of weather , usually over a 30-year interval . It is measured by assessing the patterns of variation in temperature , humidity , atmospheric pressure , wind , precipitation , atmospheric particle count and other meteorological variables in a given region over long periods of time . Climate differs from weather , in that weather only describes the short-term conditions of these variables in a given region .   A region 's climate is generated by the climate system , which has five components : atmosphere , hydrosphere , cryosphere , lithosphere , and biosphere .   The climate of a location is affected by its latitude , terrain , and altitude , as well as nearby water bodies and their currents . Climates can be classified according to the average and the typical ranges of different variables , most commonly temperature and precipitation . The most commonly used classification scheme was the Köppen climate classification . The Thornthwaite system , in use since 1948 , incorporates evapotranspiration along with temperature and precipitation information and is used in studying biological diversity and how climate change affects it . The Bergeron and Spatial Synoptic Classification systems focus on the origin of air masses that define the climate of a region .   Paleoclimatology is the study of ancient climates . Since direct observations of climate are not available before the 19th century , paleoclimates are inferred from proxy variables that include non-biotic evidence such as sediments found in lake beds and ice cores , and biotic evidence such as tree rings and coral . Climate models are mathematical models of past , present and future climates . Climate change may occur over long and short timescales from a variety of factors ; recent warming is discussed in global warming . Global warming results in redistributions . For example , `` a 3 ° C change in mean annual temperature corresponds to a shift in isotherms of approximately 300 -- 400 km in latitude ( in the temperate zone ) or 500 m in elevation . Therefore , species are expected to move upwards in elevation or towards the poles in latitude in response to shifting climate zones '' .


Climate Change Act 2008

The Climate Change Act 2008 ( c 27 ) is an Act of the Parliament of the United Kingdom . The Act makes it the duty of the Secretary of State to ensure that the net UK carbon account for all six Kyoto greenhouse gases for the year 2050 is at least 80 % lower than the 1990 baseline , toward avoiding dangerous climate change . The Act aims to enable the United Kingdom to become a low-carbon economy and gives ministers powers to introduce the measures necessary to achieve a range of greenhouse gas reduction targets . An independent Committee on Climate Change has been created under the Act to provide advice to UK Government on these targets and related policies . In the act Secretary of State refers to the Secretary of State for Energy and Climate Change .


Climate change, industry and society

This article is about climate change , industry and society .


Climate change (general concept)

Climate variability includes all the variations in the climate that last longer than individual weather events, whereas the term climate change only refers to those variations that persist for a longer period of time, typically decades or more. In the time since the industrial revolution the climate has increasingly been affected by human activities that are causing global warming and climate change.The climate system receives nearly all of its energy from the sun. The climate system also radiates energy to outer space. The balance of incoming and outgoing energy, and the passage of the energy through the climate system, determines Earth\'s energy budget. When the incoming energy is greater than the outgoing energy, earth\'s energy budget is positive and the climate system is warming. If more energy goes out, the energy budget is negative and earth experiences cooling.\nThe energy moving through Earth\'s climate system finds expression in weather, varying on geographic scales and time. Long-term averages and variability of weather in a region constitute the region\'s climate. Such changes can be the result of "internal variability", when natural processes inherent to the various parts of the climate system alter the distribution of energy. Examples include variability in ocean basins such as the Pacific decadal oscillation and Atlantic multidecadal oscillation. Climate variability can also result from external forcing, when events outside of the climate system\'s components nonetheless produce changes within the system. Examples include changes in solar output and volcanism.\nClimate variability has consequences for sea level changes, plant life, and mass extinctions; it also affects human societies.


Climate change adaptation

Climate change adaptation is a response to global warming and climate change , that seeks to reduce the vulnerability of social and biological systems to relatively sudden change and thus offset the effects of global warming . Even if emissions are stabilized relatively soon , global warming and its effects will last many years , and adaptation will be necessary to the resulting changes in climate . Adaptation is especially important in developing countries since those countries are predicted to bear the brunt of the effects of global warming . That is , the capacity and potential for humans to adapt ( called adaptive capacity ) is unevenly distributed across different regions and populations , and developing countries generally have less capacity to adapt ( Schneider et al. , 2007 ) . Furthermore , the degree of adaptation correlates to the situational focus on environmental issues . Therefore , adaptation requires the situational assessment of sensitivity and vulnerability to environmental impacts . Adaptive capacity is closely linked to social and economic development ( IPCC , 2007 ) . The economic costs of adaptation to climate change are likely to cost billions of dollars annually for the next several decades , though the amount of money needed is unknown . Donor countries promised an annual $ 100 billion by 2020 through the Green Climate Fund for developing countries to adapt to climate change . However , while the fund was set up during COP16 in Cancún , concrete pledges by developed countries have not been forthcoming . The adaptation challenge grows with the magnitude and the rate of climate change .   Another response to climate change , known as climate change mitigation ( Verbruggen , 2007 ) is to reduce greenhouse gas ( GHG ) emissions and/or enhance the removal of these gases from the atmosphere ( through carbon sinks ) . Even the most effective reductions in emissions , however , would not prevent further climate change impacts , making the need for adaptation unavoidable ( Klein et al. , 2007 ) . In a literature assessment , Klein et al. ( 2007 ) assessed options for adaptation . They concluded , with very high confidence , that in the absence of mitigation efforts , the effects of climate change would reach such a magnitude as to make adaptation impossible for some natural ecosystems . Others are concerned that climate adaptation programs might interfere with the existing development programs and thus lead to unintended consequences for vulnerable groups . For human systems , the economic and social costs of unmitigated climate change would be very high .


Climate change and agriculture

-RSB-   Climate change and agriculture are interrelated processes , both of which take place on a global scale . Climate change affects agriculture in a number of ways , including through changes in average temperatures , rainfall , and climate extremes ( e.g. , heat waves ) ; changes in pests and diseases ; changes in atmospheric carbon dioxide and ground-level ozone concentrations ; changes in the nutritional quality of some foods ; and changes in sea level .   Climate change is already affecting agriculture , with effects unevenly distributed across the world . Future climate change will likely negatively affect crop production in low latitude countries , while effects in northern latitudes may be positive or negative . Climate change will probably increase the risk of food insecurity for some vulnerable groups , such as the poor .   Agriculture contributes to climate change by ( 1 ) anthropogenic emissions of greenhouse gases ( GHGs ) , and ( 2 ) by the conversion of non-agricultural land ( e.g. , forests ) into agricultural land . Agriculture , forestry and land-use change contributed around 20 to 25 % to global annual emissions in 2010 .   There are a range of policies that can reduce the risk of negative climate change impacts on agriculture , and to reduce GHG emissions from the agriculture sector .


Climate change and ecosystems

This article is about climate change and ecosystems .


Climate change and gender

Climate change and gender is concerned with gender differences in the context of climate change and the complex and intersecting power relations arising from it . By altering the ecosystems of the planet , climate change , and more specifically global warming , directly impacts the human race . These effects vary for different segments of the population , specifically for people of different genders . In many cases , women are more vulnerable to the negative effects of climate change because of their lower social status in most countries . Many impoverished women , especially those in the developing world , are farmers and depend on the natural environment for subsistence and income . By further limiting their already constrained access to physical , social , political , and fiscal resources , climate change often burdens women more than men .   Locally and globally , both governments and non-governmental organizations respond to climate change . Some of these efforts focus on mitigating the effects of climate change while others aid societies in adapting their lifestyles to changes in their environment . Most policy responses in the late 20th and early 21st century either did not focus on the social effects of climate change or did not consider gender in these efforts .   Analysis of gender in climate change , however , not only means applying a binary male/female system of analysis on sets of quantitative data but also scrutinizing discursive constructions that shapes power relations connected to climate change .


Climate change denial

Climate change denial , or global warming denial , is part of the global warming controversy . It involves denial , dismissal , unwarranted doubt or contrarian views which strongly depart from the scientific opinion on climate change , including the extent to which it is caused by humans , its impacts on nature and human society , or the potential of adaptation to global warming by human actions . Some deniers do endorse the term , but others often prefer the term climate change skepticism , although this is a misnomer for those who deny anthropogenic global warming . In effect , the two terms form a continuous , overlapping range of views , and generally have the same characteristics : both reject , to a greater or lesser extent , mainstream scientific opinion on climate change . Climate change denial can also be implicit , when individuals or social groups accept the science but fail to come to terms with it or to translate their acceptance into action . Several social science studies have analyzed these positions as forms of denialism .   Campaigning to undermine public trust in climate science has been described as a `` denial machine '' of industrial , political and ideological interests , supported by conservative media and skeptical bloggers in manufacturing uncertainty about global warming . In the public debate , phrases such as climate skepticism have frequently been used with the same meaning as climate denialism . The labels are contested : those actively challenging climate science commonly describe themselves as `` skeptics '' , but many do not comply with common standards of scientific skepticism and , regardless of evidence , persistently deny the validity of human caused global warming .   Although scientific opinion on climate change is that human activity is extremely likely to be the primary driver of climate change , the politics of global warming have been affected by climate change denial , hindering efforts to prevent climate change and adapt to the warming climate . Those promoting denial commonly use rhetorical tactics to give the appearance of a scientific controversy where there is none .   Of the world 's countries , the climate change denial industry is most powerful in the United States . Since January 2015 , the United States Senate Committee on Environment and Public Works has been chaired by oil lobbyist and climate change denier Jim Inhofe . Inhofe is notorious for having called climate change `` the greatest hoax ever perpetrated against the American people '' and for having claimed to have debunked the alleged hoax in February 2015 when he brought a snowball with him in the Senate chamber and tossed it across the floor . Organised campaigning to undermine public trust in climate science is associated with conservative economic policies and backed by industrial interests opposed to the regulation of emissions . Climate change denial has been associated with the fossil fuels lobby , the Koch brothers , industry advocates and libertarian think tanks , often in the United States . More than 90 % of papers sceptical on climate change originate from right-wing think tanks .  The total annual income of these climate change counter-movement-organizations is roughly $ 900 million . Between 2002 and 2010 , nearly $ 120 million ( # 77 million ) was anonymously donated via the Donors Trust and Donors Capital Fund to more than 100 organisations seeking to undermine the public perception of the science on climate change . In 2013 the Center for Media and Democracy reported that the State Policy Network ( SPN ) , an umbrella group of 64 U.S. think tanks , had been lobbying on behalf of major corporations and conservative donors to oppose climate change regulation .   Since the late 1970s , oil companies have published research broadly in line with the standard views on global warming . Despite this , oil companies organized a climate change denial campaign to disseminate public disinformation for several decades , a strategy that has been compared to the organized denial of the hazards of tobacco smoking by tobacco companies .


Climate change feedback

Climate change feedback is important in the understanding of global warming because feedback processes may amplify or diminish the effect of each climate forcing , and so play an important part in determining the climate sensitivity and future climate state . Feedback in general is the process in which changing one quantity changes a second quantity , and the change in the second quantity in turn changes the first . Positive feedback amplifies the change in the first quantity while negative feedback reduces it .   The term `` forcing '' means a change which may `` push '' the climate system in the direction of warming or cooling . An example of a climate forcing is increased atmospheric concentrations of greenhouse gases . By definition , forcings are external to the climate system while feedbacks are internal ; in essence , feedbacks represent the internal processes of the system . Some feedbacks may act in relative isolation to the rest of the climate system ; others may be tightly coupled ; hence it may be difficult to tell just how much a particular process contributes . Forcings , feedbacks and the dynamics of the climate system determine how much and how fast the climate changes . The main positive feedback in global warming is the tendency of warming to increase the amount of water vapor in the atmosphere , which in turn leads to further warming . The main negative feedback comes from the Stefan -- Boltzmann law , the amount of heat radiated from the Earth into space changes with the fourth power of the temperature of Earth 's surface and atmosphere .   Some observed and potential effects of global warming are positive feedbacks , which contribute directly to further global warming . The Intergovernmental Panel on Climate Change 's ( IPCC ) Fourth Assessment Report states that `` Anthropogenic warming could lead to some effects that are abrupt or irreversible , depending upon the rate and magnitude of the climate change . ''


Climate change in Australia

Climate change has been a major issue in Australia since the beginning of the 21st century . In 2013 , the CSIRO released a report stating that Australia is becoming hotter , and that it will experience more extreme heat and longer fire seasons because of climate change . In 2014 , the Bureau of Meteorology released a report on the state of Australia 's climate that highlighted several key points , including the significant increase in Australia 's temperatures ( particularly night-time temperatures ) and the increasing frequency of bush fires , droughts and floods , which have all been linked to climate change .   Since the beginning of the 20th century Australia has experienced an increase of nearly 1 ° C in average annual temperatures , with warming occurring at twice the rate over the past 50 years than in the previous 50 years . Recent climate events such as extremely high temperatures and widespread drought have focused government and public attention on the impacts of climate change in Australia . Rainfall in southwestern Australia has decreased by 10 -- 20 % since the 1970s , while southeastern Australia has also experienced a moderate decline since the 1990s . Rainfall patterns are expected to be problematic , as rain has become heavier and infrequent , as well as more common in summer rather than in winter , with little or no uptrend in rainfall in the Western Plateau and the Central Lowlands of Australia . Water sources in the southeastern areas of Australia have depleted due to increasing population in urban areas ( rising demand ) coupled with climate change factors such as persistent prolonged drought ( diminishing supply ) . At the same time , Australia continues to have the highest per capita greenhouse gas emissions . Temperatures in Australia have also risen dramatically since 1910 and nights have become warmer .   A carbon tax was introduced in 2011 by the Gillard government in an effort to reduce the impact of climate change and despite some criticism , it successfully reduced Australia 's carbon dioxide emissions , with coal generation down 11 % since 2008 -- 09 . The subsequent Australian Government , elected in 2013 under then Prime Minister Tony Abbott was criticised for being `` in complete denial about climate change '' . Furthermore , the Abbott government repealed the carbon tax on 17 July 2014 in a heavily criticised move . The renewable energy target ( RET ) , launched in 2001 , was heavily modified under Abbott 's government . However , under the government of Malcolm Turnbull , Australia attended the 2015 United Nations Climate Change Conference and adopted the Paris Agreement . This agreement includes a review of emission reduction targets every 5 years from 2020 .   The federal government and all state governments ( New South Wales , Victoria , Queensland , South Australia , Western Australia , Tasmania , Northern Territory and the Australian Capital Territory ) have explicitly recognised that climate change is being caused by greenhouse gas emissions , in conformity with the scientific opinion on climate change . Sectors of the population have campaigned against new coal mines and coal-fired power stations , reflecting concerns about the effects of global warming on Australia .  The Garnaut Climate Change Review predicted that a net benefit to Australia may be derived by stabilising greenhouse gases in the atmosphere at 450ppm CO2 eq .   The per-capita carbon footprint in Australia was rated 12th in the world by PNAS in 2011 , considerably large given the small population of the country .


Climate change in Canada

In Canada mitigation of anthropogenic climate change is being addressed more seriously by the provinces than by the federal government . The 2015 election signals greater federal leadership as noted in Canada 's National Statement at COP21 , making climate change a top priority , and pledging actions based on the best scientific evidence and advice .


Climate change in Tuvalu

Global warming (recent climate change) is particularly threatening in Tuvalu. This is because the average height of the islands is less than 2 metres (6.6 ft) above sea level, with the highest point of Niulakita being about 4.6 metres (15 ft) above sea level. Between 1971 and 2014, during a period of global warming, Tuvalu islands have increased in size, according to aerial photography and satellite imagery. Over four decades, there was a net increase in land area in Tuvalu of 73.5 ha (2.9%), although the changes were not uniform, with 74% of land increasing in size and 27% of land decreasing in size. The sea level at the Funafuti tide gauge has risen at 3.9 mm per year, which is approximately twice the global average.Tuvalu could be one of the first nations to be significantly impacted by rising sea levels. Not only could parts of the island be flooded but the rising saltwater table could also destroy deep rooted food crops such as coconut, pulaka, and taro. Research from the University of Auckland suggests that Tuvalu may remain habitable over the next century. However, as of March 2018, Prime Minister Enele Sopoaga stated that Tuvalu is not expanding and has gained no additional habitable land. Sopoaga has also said that evacuating the islands is the last resort.


Climate change in Washington

Climate change in the US state of Washington is a subject of study and projection today .


Climate change in the Arctic

The effects of global warming in the Arctic , or climate change in the Arctic include rising temperatures , loss of sea ice , and melting of the Greenland ice sheet with a related cold temperature anomaly , observed in recent years . Potential methane release from the region , especially through the thawing of permafrost and methane clathrates , is also a concern . The Arctic warms twice as fast compared to the rest of the world . The pronounced warming signal , the amplified response of the Arctic to global warming , it is often seen as a leading indicator of global warming . The melting of Greenland 's ice sheet is linked to polar amplification . According to a study published in 2016 , about 0.5 ◦ C of the warming in the Arctic has been attributed to reductions in sulfate aerosols in Europe since 1980 .


Climate change in the United States

Because of global warming , there has been concern in the United States and internationally , that the country should reduce total greenhouse gas which is relatively high per capita .   In 2012 , the United States experienced its warmest year on record . , the thirteen warmest years for the entire planet have all occurred since 1998 , transcending those from 1880 .   From 1950 to 2009 , the American government 's surface temperature record shows an increase by 1 F-change , approximately . Global warming has caused many changes in the U.S. . According to a 2009 statement by the National Oceanic and Atmospheric Administration ( NOAA ) , trends include lake and river ice melting earlier in the spring , plants blooming earlier , multiple animal species shifting their habitat ranges northward , and reductions in the size of glaciers .   Predicting future climate changes are fraught with difficulty . Some research has warned against possible problems due to American climate changes such as the spread of invasive species and possibilities of floods as well as droughts . Changes in climate in the regions of the United States appear significant . Drought conditions appear to be worsening in the southwest while improving in the northeast for example .   President Barack Obama committed in the December 2009 Copenhagen Climate Change Summit to reduce carbon dioxide emissions in the range of 17 % below 2005 levels by 2020 , 42 % below 2005 levels by 2030 , and 83 % below 2005 levels by 2050 . In an address towards the U.S. Congress in June 2013 , Obama detailed a specific action plan to achieve the 17 % carbon emissions cut from 2005 by 2020 . He included such measures as shifting from coal-based power generation to solar and natural gas production .   Climate change is seen as a national security threat to the United States .   In 2015 , according to The New York Times and others , oil companies knew that burning oil and gas could cause global warming since the 1970s but , nonetheless , funded deniers for years .   2016 was an historic year for billion-dollar weather and climate disasters in U.S.


Climate change mitigation

Climate change mitigation consists of actions to limit the magnitude or rate of long-term climate change . Climate change mitigation generally involves reductions in human ( anthropogenic ) emissions of greenhouse gases ( GHGs ) . Mitigation may also be achieved by increasing the capacity of carbon sinks , e.g. , through reforestation . Mitigation policies can substantially reduce the risks associated with human-induced global warming .   According to the IPCC 's 2014 assessment report , `` Mitigation is a public good ; climate change is a case of the ` tragedy of the commons . Effective climate change mitigation will not be achieved if each agent ( individual , institution or country ) acts independently in its own selfish interest ( see international cooperation and emissions trading ) , suggesting the need for collective action . Some adaptation actions , on the other hand , have characteristics of a private good as benefits of actions may accrue more directly to the individuals , regions , or countries that undertake them , at least in the short term . Nevertheless , financing such adaptive activities remains an issue , particularly for poor individuals and countries . ''   Examples of mitigation include phasing out fossil fuels by switching to low-carbon energy sources , such as renewable and nuclear energy , and expanding forests and other `` sinks '' to remove greater amounts of carbon dioxide from the atmosphere . Energy efficiency may also play a role , for example , through improving the insulation of buildings . Another approach to climate change mitigation is climate engineering .   Most countries are parties to the United Nations Framework Convention on Climate Change ( UNFCCC ) . The ultimate objective of the UNFCCC is to stabilize atmospheric concentrations of GHGs at a level that would prevent dangerous human interference of the climate system . Scientific analysis can provide information on the impacts of climate change , but deciding which impacts are dangerous requires value judgments .   In 2010 , Parties to the UNFCCC agreed that future global warming should be limited to below 2.0 ° C ( 3.6 ° F ) relative to the pre-industrial level . With the Paris Agreement of 2015 this was confirmed , but was revised with a new target laying down `` parties will do the best '' to achieve warming below 1.5 ° C . The current trajectory of global greenhouse gas emissions does not appear to be consistent with limiting global warming to below 1.5 or 2 ° C . Other mitigation policies have been proposed , some of which are more stringent or modest than the 2 ° C limit .


Climate change policy of the United States

Global climate change was first addressed in United States policy beginning in the early 1960s . The Environmental Protection Agency ( EPA ) defines climate change as `` any significant change in the measures of climate lasting for an extended period of time . '' Essentially , climate change includes major changes in temperature , precipitation , or wind patterns , as well as other effects , that occur over several decades or longer . Climate change policy in the US has transformed rapidly over the past twenty years and is being developed at both the state and federal level . The politics of global warming and climate change have polarized certain political parties and other organizations . This article focuses on climate change policy within the United States , as well as exploring the positions of various parties and the influences on policy making and environmental justice repercussions .


Climate engineering

Climate engineering , commonly referred to as geoengineering , also known as climate intervention , is the deliberate and large-scale intervention in the Earth 's climatic system with the aim of limiting adverse global warming . Climate engineering is an umbrella term for measures that mainly fall into two types : carbon dioxide removal and solar radiation management . Carbon dioxide removal addresses the cause of global warming by removing one of the greenhouse gases ( carbon dioxide ) from the atmosphere . Solar radiation management attempts to offset effects of greenhouse gases by causing the Earth to absorb less solar radiation .   Climate engineering approaches are sometimes viewed as additional potential options for limiting global warming , alongside mitigation and adaptation . There is substantial agreement among scientists that climate engineering can not substitute for climate change mitigation . Some approaches might be used as accompanying measures to sharp cuts in greenhouse gas emissions . Given that all types of measures for addressing climate change have economic , political , or physical limitations , some climate engineering approaches might eventually be used as part of an ensemble of measures . Research on costs , benefits , and various types of risks of most climate engineering approaches is at an early stage and their understanding needs to improve to judge their adequacy and feasibility .   Almost all research into solar radiation management has consisted of computer modelling or laboratory tests , and an attempt to move to outdoor experimentation was controversial . Some carbon dioxide removal practices , such as planting of trees and bio-energy with carbon capture and storage projects , are underway . Their scalability to effectively affect global climate is , however , debated . Ocean iron fertilization has been given small-scale research trials , sparking substantial controversy .   Most experts and major reports advise against relying on climate engineering techniques as a simple solution to global warming , in part due to the large uncertainties over effectiveness and side effects . However , most experts also argue that the risks of such interventions must be seen in the context of risks of dangerous global warming . Interventions at large scale may run a greater risk of disrupting natural systems resulting in a dilemma that those approaches that could prove highly ( cost - ) effective in addressing extreme climate risk , might themselves cause substantial risk . Some have suggested that the concept of engineering the climate presents a so-called `` moral hazard '' because it could reduce political and public pressure for emissions reduction , which could exacerbate overall climate risks ; others assert that the threat of climate engineering could spur emissions cuts .  Some are in favour of a moratorium on out-of-doors testing and deployment of solar radiation management ( SRM ) .


Climate model

Climate models use quantitative methods to simulate the interactions of the important drivers of climate , including atmosphere , oceans , land surface and ice . They are used for a variety of purposes from study of the dynamics of the climate system to projections of future climate .   All climate models take account of incoming energy from the sun as short wave electromagnetic radiation , chiefly visible and short-wave ( near ) infrared , as well as outgoing long wave ( far ) infrared electromagnetic . Any imbalance results in a change in temperature .   Models vary in complexity :  A simple radiant heat transfer model treats the earth as a single point and averages outgoing energy  This can be expanded vertically ( radiative-convective models ) and/or horizontally  Finally , ( coupled ) atmosphere -- ocean -- sea ice global climate models solve the full equations for mass and energy transfer and radiant exchange .  Box models can treat flows across and within ocean basins .  Other types of modelling can be interlinked , such as land use , allowing researchers to predict the interaction between climate and ecosystems .


Climate of Antarctica

The climate of Antarctica is the coldest on Earth . Antarctica 's lowest air temperature record was set on 21 July 1983 , with − 89.2 C at Vostok Station . Satellite measurements have identified even lower ground temperatures , down to − 93.2 C at the cloud free East Antarctic Plateau on 10 August 2010 . It is also extremely dry ( technically a desert ) , averaging 166 mm of precipitation per year . On most parts of the continent the snow rarely melts and is eventually compressed to become the glacier ice that makes up the ice sheet . Weather fronts rarely penetrate far into the continent , because of the katabatic winds . Most of Antarctica has an ice cap climate ( Köppen EF ) with very cold , generally extremely dry weather .


Climate of Argentina

The climate of Argentina is a complex subject : the vast size of the country and considerable variation in altitude make for a wide range of climate types . Argentina has four seasons : winter ( June -- August ) , spring ( September -- November ) , summer ( December -- February ) and autumn ( March -- May ) , all featuring different weather conditions . Summers are the warmest and wettest season in most of the country except in most of Patagonia where it is the driest season . Winters are normally mild in the north , cool in the center and cold in the southern parts with the latter experiencing frequent frost and snow . Because southern parts of the country are moderated by the surrounding oceans , the cold is less intense and prolonged than areas at comparable latitudes in the northern hemisphere . Spring and autumn are transition seasons that generally feature mild weather .   Many regions have different , often contrasting , microclimates . In general , northern parts of the country are characterized by hot , humid , rainy summers and mild winters with periodic droughts . Mesopotamia , in the northeast is characterized by high temperatures and abundant precipitation throughout the year with droughts being uncommon . West of this lies the Chaco region , which is the warmest region in Argentina . Precipitation in the Chaco region decreases westwards , resulting in the vegetation changing from forests in the east to shrubs in the west . Northwest Argentina is predominantly dry and hot although the rugged topography makes it climatically diverse , ranging from the cold , dry Puna to thick jungles . The center of the country , which includes the Pampas to the east and the drier Cuyo region to the west has hot summers with occasional tornadoes and thunderstorms , and cool , dry winters . Patagonia , in the southern parts of the country has a dry climate with warm summers and cold winters characterized by strong winds throughout the year and one of the strongest precipitation gradients in the world . High elevations at all latitudes experience cooler conditions , and the mountainous zones can see heavy snowfall .   The geographic and geomorphic characteristics of Argentina tend to create extreme weather conditions , often leading to natural disasters that negatively impact the country both economically and socially . The Pampas , where many of the large cities are located , has a flat topography and poor water drainage , making it vulnerable to flooding . Severe storms can lead to tornados , damaging hail , storm surges , and high winds , causing extensive damage to houses and infrastructure , displacing thousands of people and causing significant loss of life . Extreme temperature events such as heat waves and cold waves impact rural and urban areas by negatively impacting agriculture , one of the main economic activities of the country , and by increasing energy demand , which can lead to energy shortages .   Argentina is vulnerable and will likely be significantly impacted by climate change . Temperatures have increased in the last century while the observed changes in precipitation are variable , with some areas receiving more and other areas less . These changes have impacted river flow , increased the frequency of extreme weather events , and led to the retreat of glaciers . Based on the projections for both precipitation and temperatures , these climatic events are likely to increase in severity and create new problems associated with climate change in the country .


Climate of Asia

The Climate of Asia is wet across southeast sections , and dry across much of the interior . Some of the largest daily temperature ranges on Earth occur in western sections of Asia . The monsoon circulation dominates across southern and eastern sections , due to the presence of the Himalayas forcing the formation of a thermal low which draws in moisture during the summer . Southwestern sections of the continent experience low relief as a result of the subtropical high pressure belt ; they are hot in the summer , warm to cool in winter , and may snow at higher altitudes . Siberia is one of the coldest places in the Northern Hemisphere , and can act as a source of arctic air masses for North America . The most active place on Earth for tropical cyclone activity lies northeast of the Philippines and south of Japan , and the phase of the El Niño-Southern Oscillation modulates where in Asia landfall is more likely to occur ,


Climate of Australia

Australia 's climate is governed largely by its size and by the hot , sinking air of the subtropical high pressure belt . This moves north and south with the seasons , so that the rainfall pattern over Australia is highly seasonal . Australia 's rainfall is the lowest of all continents except Antarctica . But it is variable , with frequent droughts lasting several seasons -- thought to be caused in part by the El Niño-Southern Oscillation . The climate varies widely due to its large geographical size , but by far the largest part of Australia is desert or semi-arid . Only the south-east and south-west corners have a temperate climate and moderately fertile soil . The northern part of the country has a tropical climate , varied between tropical rainforests , grasslands and part dessert .   Because Australia is a small continent , separated from polar regions by the Southern Ocean , it is not subject to the movements of frigid polar air that sweep over Northern Hemisphere continents during winter . Consequently , its winter is relatively mild , so that there is n't the great contrast between summer and winter temperatures there is in the northern continents . Yet in many parts of the country , seasonal highs and lows can be considerable : temperatures have ranged from above 50 C to well below zero . Nonetheless , minimum temperatures are moderated .   The El Niño-Southern Oscillation is associated with seasonal abnormality in many areas in the world . Australia is one of the continents most affected and experiences extensive droughts alongside considerable wet periods . Occasionally a dust storm will blanket a region and there are reports of the occasional tornado . Tropical cyclones , heat waves , bushfires and frosts in the country are also associated with the Southern Oscillation . Rising levels of salinity and desertification in some areas is ravaging the landscape .   Climate change in Australia is a highly contentious issue . Temperatures in the country have risen following an increasing trend of global warming between the years of 1910 to 2004 by approximately 0.7 ° C. Overnight minimum temperatures have warmed more rapidly than daytime maximum temperatures in recent years . The late-20th century warming has been largely attributed to the increased greenhouse effect . According to the Bureau of Meteorology , 80 % of the land has less than 600 mm of rainfall per year and 50 % has even less than 300 mm . As a whole , Australia has a very low annual average rainfall of 419 mm .


Climate of Chicago

The climate of Chicago is classified as humid continental ( Köppen Dfa ) , with all four seasons distinctly represented : wet , cool springs ; somewhat hot , and often humid , summers ; pleasantly mild autumns ; and cold winters . Annual precipitation in Chicago is average , and reaches its lowest points in the months of January and February , and peaks in the months of May and June . Chicago 's weather is influenced by the nearby presence of Lake Michigan during all four seasons .


Climate of Florida

The climate of the north and central parts of the US state of Florida is humid subtropical . South Florida has a tropical climate . There is a defined rainy season from May through October , when air mass thundershowers that build in the heat of the day drop heavy but brief summer rainfall . Late summer and early fall bring decaying tropical lows ( and occasionally landfalling tropical cyclones ) that contribute to late summer and early fall rains   In October the dry season sets in across much of Florida ( starting early in the month in northern Florida and near the end of the month in deep southern Florida ) and lasts until late April in most years . Fronts from mid-latitude storms north of Florida occasionally pass through northern and central parts of the state which bring light and brief winter rainfall . Mid and late winter can become severely dry in Florida . In some years the dry season becomes quite severe and water restrictions are imposed to conserve water . While most areas of Florida do not experience any type of frozen precipitation , north Florida can see fleeting snow or sleet a few times each decade .   The Gulf Stream running through the Florida Straits and then north off the Florida East Coast keeps temperatures moderate a few miles inland from around Stuart on the east coast to Ft. Myers on the west side of the state year round , with few extremes in temperature . The tropical ocean current also provides warm sea surface temperatures , giving Florida beaches the warmest ocean surf waters on the United States mainland .


Climate of India

The climate of India comprises a wide range of weather conditions across a vast geographic scale and varied topography , making generalisations difficult . Based on the Köppen system , India hosts six major climatic subtypes , ranging from arid desert in the west , alpine tundra and glaciers in the north , and humid tropical regions supporting rainforests in the southwest and the island territories . Many regions have starkly different microclimates . The nation has four seasons : winter ( December , January and February ) , summer ( March , April and May ) , a monsoon rainy season ( June to September ) , and a post-monsoon period ( October to November ) .   India 's geography and geology are climatically pivotal : the Thar Desert in the northwest and the Himalayas in the north work in tandem to effect a culturally and economically important monsoonal regime . As Earth 's highest and most massive mountain range , the Himalayas bar the influx of frigid katabatic winds from the icy Tibetan Plateau and northerly Central Asia . Most of North India is thus kept warm or is only mildly chilly or cold during winter ; the same thermal dam keeps most regions in India hot in summer .   Though the Tropic of Cancer -- the boundary between the tropics and subtropics -- passes through the middle of India , the bulk of the country can be regarded as climatically tropical . As in much of the tropics , monsoonal and other weather patterns in India can be wildly unstable : epochal droughts , floods , cyclones , and other natural disasters are sporadic , but have displaced or ended millions of human lives . There is one scientific opinion which states that in South Asia such climatic events are likely to change in unpredictability , frequency , and severity . Ongoing and future vegetative changes and current sea level rises and the attendant inundation of India 's low-lying coastal areas are other impacts , current or predicted , that are attributable to global warming .


Climate of Mars

The climate of Mars has been an issue of scientific curiosity for centuries , in part because Mars is the only terrestrial planet whose surface can be directly observed in detail from the Earth with help from a telescope .   Although Mars is smaller than the Earth , at 11 % of Earth 's mass , and 50 % farther from the Sun than the Earth , its climate has important similarities , such as the polar ice caps , seasonal changes and the observable presence of weather patterns . It has attracted sustained study from planetologists and climatologists . While Mars 's climate has similarities to Earth 's , including periodic ice ages , there are also important differences , such as much lower thermal inertia . Mars ' atmosphere has a scale height of approximately 11 km , 60 % greater than that on Earth . The climate is of considerable relevance to the question of whether life is or was present on the planet . The climate briefly received more interest in the news due to NASA measurements indicating increased sublimation of the south polar icecap leading to some popular press speculation that Mars was undergoing a parallel bout of global warming , although Mars ' average temperature has actually cooled in recent decades .   Mars has been studied by Earth-based instruments since the 17th century but it is only since the exploration of Mars began in the mid-1960s that close-range observation has been possible . Flyby and orbital spacecraft have provided data from above , while direct measurements of atmospheric conditions have been provided by a number of landers and rovers . Advanced Earth orbital instruments today continue to provide some useful `` big picture '' observations of relatively large weather phenomena .   The first Martian flyby mission was Mariner 4 which arrived in 1965 . That quick two-day pass ( July 14 -- 15 , 1965 ) was limited and crude in terms of its contribution to the state of knowledge of Martian climate . Later Mariner missions ( Mariner 6 , and Mariner 7 ) filled in some of the gaps in basic climate information . Data-based climate studies started in earnest with the Viking program in 1975 and continues with such probes as the Mars Reconnaissance Orbiter .   This observational work has been complemented by a type of scientific computer simulation called the Mars general circulation model . Several different iterations of MGCM have led to an increased understanding of Mars as well as the limits of such models .


Climate of the Arctic

The climate of the Arctic is characterized by long , cold winters and short , cool summers . There is a large amount of variability in climate across the Arctic , but all regions experience extremes of solar radiation in both summer and winter . Some parts of the Arctic are covered by ice ( sea ice , glacial ice , or snow ) year-round , and nearly all parts of the Arctic experience long periods with some form of ice on the surface . Average January temperatures range from about − 34 ° C to 0 ° C ( − 40 to +32 ° F ) , and winter temperatures can drop below − 50 ° C ( − 58 ° F ) over large parts of the Arctic . Average July temperatures range from about − 10 to +10 ° C ( 14 to 50 ° F ) , with some land areas occasionally exceeding 30 ° C ( 86 ° F ) in summer .   The Arctic consists of ocean that is largely surrounded by land . As such , the climate of much of the Arctic is moderated by the ocean water , which can never have a temperature below − 2 ° C ( 28 ° F ) . In winter , this relatively warm water , even though covered by the polar ice pack , keeps the North Pole from being the coldest place in the Northern Hemisphere , and it is also part of the reason that Antarctica is so much colder than the Arctic . In summer , the presence of the nearby water keeps coastal areas from warming as much as they might otherwise .


Climate of the United Kingdom

The United Kingdom straddles the higher mid-latitudes between 49 ° and 61 ° N . It is on the western seaboard of Afro-Eurasia , the world 's largest land mass . These conditions allow convergence between moist maritime air and dry continental air . In this area , the large temperature variation creates atmospheric instability , and this is a major factor that influences the often unsettled weather the country experiences : where many types of weather can be experienced in a single day . In general the climate of the UK is cool and often cloudy , and hot temperatures are infrequent .   The climate in the United Kingdom is defined as a temperate oceanic climate , or Cfb on the Köppen climate classification system , a classification it shares with most of north-west Europe . Regional climates are influenced by the Atlantic Ocean and latitude . Northern Ireland , Wales and western parts of England and Scotland , being closest to the Atlantic Ocean , are generally the mildest , wettest and windiest regions of the UK , and temperature ranges here are seldom extreme . Eastern areas are drier , cooler , less windy and also experience the greatest daily and seasonal temperature variations . Northern areas are generally cooler , wetter and have slightly larger temperature ranges than southern areas .   Though the UK is mostly under the influence of the maritime tropical air mass from the south-west , different regions are more susceptible than others when different air masses affect the country : Northern Ireland and the west of Scotland are the most exposed to the maritime polar air mass which brings cool moist air ; the east of Scotland and north-east England are more exposed to the continental polar air mass which brings cold dry air ; the south and south-east of England are more exposed to the continental tropical air mass which brings warm dry air ( and consequently most of the time the warmest summer temperatures ) ; and Wales and south-west England are the most exposed to the maritime tropical air mass which brings warm moist air .   If the air masses are strong enough in their respective areas during the summer , there can sometimes be a large difference in temperature between the far north of Scotland ( including the Islands ) and south-east of England -- often a difference of 10 -- 15 ° C ( 18-27 ° F ) but sometimes of as much as 20 ° C ( 36 ° F ) or more . In the height of summer the Northern Isles could have temperatures around 15 ° C ( 59 ° F ) and areas around London could reach 30 ° C ( 86 ° F ) .


Climate sensitivity

Climate sensitivity is the equilibrium temperature change in response to changes of the radiative forcing . Therefore , climate sensitivity depends on the initial climate state , but potentially can be accurately inferred from precise palaeoclimate data . Slow climate feedbacks , especially changes of ice sheet size and atmospheric CO2 , amplify the total Earth system sensitivity by an amount that depends on the time scale considered .   Although climate sensitivity is usually used in the context of radiative forcing by carbon dioxide ( CO2 ) , it is thought of as a general property of the climate system : the change in surface air temperature ( ΔTs ) following a unit change in radiative forcing ( RF ) , and thus is expressed in units of ° C / ( W/m2 ) . For this to be useful , the measure must be independent of the nature of the forcing ( e.g. from greenhouse gases or solar variation ) ; to first order this is indeed found to be so .   The climate sensitivity specifically due to is often expressed as the temperature change in ° C associated with a doubling of the concentration of carbon dioxide in Earth 's atmosphere .   For coupled atmosphere-ocean global climate models ( e.g. CMIP5 ) the climate sensitivity is an emergent property : it is not a model parameter , but rather a result of a combination of model physics and parameters . By contrast , simpler energy-balance models may have climate sensitivity as an explicit parameter .   The terms represented in the equation relate radiative forcing ( RF ) to linear changes in global surface temperature change ( ΔTs ) via the climate sensitivity λ .   It is also possible to estimate climate sensitivity from observations ; however , this is difficult due to uncertainties in the forcing and temperature histories .


Climate system

Earth's climate arises from the interaction of five major climate system components: the atmosphere (air), the hydrosphere (water), the cryosphere (ice and permafrost), the lithosphere (earth's upper rocky layer) and the biosphere (living things). Climate is the average weather, typically over a period of 30 years, and is determined by a combination of processes in the climate system, such as ocean currents and wind patterns. Circulation in the atmosphere and oceans is primarily driven by solar radiation and transports heat from the tropical regions to regions that receive less energy from the Sun. The water cycle also moves energy throughout the climate system. In addition, different chemical elements, necessary for life, are constantly recycled between the different components. The climate system can change due to internal variability and external forcings. These external forcings can be natural, such as variations in solar intensity and volcanic eruptions, or caused by humans. Accumulation of heat-trapping greenhouse gases, mainly being emitted by people burning fossil fuels, is causing global warming. Human activity also releases cooling aerosols, but their net effect is far less than that of greenhouse gases. Changes can be amplified by feedback processes in the different climate system components.


Climate variability

Climate variability includes all the variations in the climate that last longer than individual weather events, whereas the term climate change only refers to those variations that persist for a longer period of time, typically decades or more. In the time since the industrial revolution the climate has increasingly been affected by human activities that are causing global warming and climate change.The climate system receives nearly all of its energy from the sun. The climate system also radiates energy to outer space. The balance of incoming and outgoing energy, and the passage of the energy through the climate system, determines Earth's energy budget. When the incoming energy is greater than the outgoing energy, earth's energy budget is positive and the climate system is warming. If more energy goes out, the energy budget is negative and earth experiences cooling. The energy moving through Earth's climate system finds expression in weather, varying on geographic scales and time. Long-term averages and variability of weather in a region constitute the region's climate. Such changes can be the result of "internal variability", when natural processes inherent to the various parts of the climate system alter the distribution of energy. Examples include variability in ocean basins such as the Pacific decadal oscillation and Atlantic multidecadal oscillation. Climate variability can also result from external forcing, when events outside of the climate system's components nonetheless produce changes within the system. Examples include changes in solar output and volcanism. Climate variability has consequences for sea level changes, plant life, and mass extinctions; it also affects human societies.


Climatic Research Unit

The Climatic Research Unit ( CRU ) is a component of the University of East Anglia and is one of the leading institutions concerned with the study of natural and anthropogenic climate change .   With a staff of some thirty research scientists and students , the CRU has contributed to the development of a number of the data sets widely used in climate research , including one of the global temperature records used to monitor the state of the climate system , as well as statistical software packages and climate models .


Climatic Research Unit documents

Climatic Research Unit documents including thousands of e-mails and other computer files were stolen from a server at the Climatic Research Unit of the University of East Anglia in a hacking incident in November 2009 . The documents were redistributed first through several blogs of global warming skeptics , and allegations were made that they indicated misconduct by leading climate scientists . A series of investigations rejected these allegations , while concluding that CRU scientists should have been more open with distributing data and methods on request . Precisely six committees investigated the allegations and published reports , finding no evidence of fraud or scientific misconduct . The scientific consensus that global warming is occurring as a result of human activity remained unchanged by the end of the investigations .   The incident occurred shortly before the opening December 2009 Copenhagen global climate summit . It has prompted general discussion about increasing the openness of scientific data ( though the majority of climate data have always been freely available ) . Scientists , scientific organisations , and government officials have stated that the incident does not affect the overall scientific case for climate change . Andrew Revkin reported in the New York Times that `` The evidence pointing to a growing human contribution to global warming is so widely accepted that the hacked material is unlikely to erode the overall argument . ''


The Climatic Research Unit email controversy ( also known as `` Climategate '' ) began in November 2009 with the hacking of a server at the Climatic Research Unit ( CRU ) at the University of East Anglia ( UEA ) by an external attacker , copying thousands of emails and computer files , the Climatic Research Unit documents , to various internet locations several weeks before the Copenhagen Summit on climate change .   The story was first broken by climate change denialists with columnist James Delingpole popularising the term `` Climategate '' to describe the controversy . Several people considered climate change `` skeptics '' argued that the emails showed global warming was a scientific conspiracy , that scientists manipulated climate data and attempted to suppress critics . The CRU rejected this , saying the emails had been taken out of context and merely reflected an honest exchange of ideas .   The mainstream media picked up the story as negotiations over climate change mitigation began in Copenhagen on 7 December 2009 . Because of the timing , scientists , policy makers and public relations experts said that the release of emails was a smear campaign intended to undermine the climate conference . In response to the controversy , the American Association for the Advancement of Science ( AAAS ) , the American Meteorological Society ( AMS ) and the Union of Concerned Scientists ( UCS ) released statements supporting the scientific consensus that the Earth 's mean surface temperature had been rising for decades , with the AAAS concluding , `` based on multiple lines of scientific evidence that global climate change caused by human activities is now underway ... it is a growing threat to society . ''   Eight committees investigated the allegations and published reports , finding no evidence of fraud or scientific misconduct . However , the reports called on the scientists to avoid any such allegations in the future by taking steps to regain public confidence in their work , for example by opening up access to their supporting data , processing methods and software , and by promptly honouring freedom of information requests . The scientific consensus that global warming is occurring as a result of human activity remained unchanged throughout the investigations .


Climatology

Climatology ( from Greek κλίμα , klima , `` place , zone '' ; and - λογία , - logia ) or climate science is the study of climate , scientifically defined as weather conditions averaged over a period of time . This modern field of study is regarded as a branch of the atmospheric sciences and a subfield of physical geography , which is one of the Earth sciences . Climatology now includes aspects of oceanography and biogeochemistry . Basic knowledge of climate can be used within shorter term weather forecasting using analog techniques such as the El Niño -- Southern Oscillation ( ENSO ) , the Madden -- Julian oscillation ( MJO ) , the North Atlantic oscillation ( NAO ) , the Northern Annular Mode ( NAM ) which is also known as the Arctic oscillation ( AO ) , the Northern Pacific ( NP ) Index , the Pacific decadal oscillation ( PDO ) , and the Interdecadal Pacific Oscillation ( IPO ) . Climate models are used for a variety of purposes from study of the dynamics of the weather and climate system to projections of future climate . Weather is known as the condition of the atmosphere over a period of time . While Climate has to do with the atmospheric condition over an extended to indefinite period of time .


Cloud

In meteorology , a cloud is an aerosol comprising a visible mass of minute liquid droplets , frozen crystals , or particles suspended in the atmosphere above the surface of a planetary body . The droplets and crystals may be made of water or various chemicals . On Earth , clouds are formed as a result of saturation of the air when it is cooled to its dew point , or when it gains sufficient moisture ( usually in the form of water vapor ) from an adjacent source to raise the dew point to the ambient temperature . They are seen in the Earth 's homosphere ( which includes the troposphere , stratosphere , and mesosphere ) . Nephology is the science of clouds which is undertaken in the cloud physics branch of meteorology .   There are two systems of naming clouds in their respective layers of the atmosphere ; Latin in the troposphere and mostly alpha-numeric above the troposphere . Cloud types in the troposphere , the atmospheric layer closest to Earth 's surface , have Latin names due to the universal adaptation of Luke Howard 's nomenclature . Formally proposed in 1802 , it became the basis of a modern international system that classifies clouds into five physical forms and three altitude levels ( formerly known as étages ) . These physical types , in approximate ascending order of convective activity , include stratiform sheets , cirriform wisps and patches , stratocumuliform layers ( mainly structured as rolls , ripples , and patches ) , cumuliform heaps , and very large cumulonimbiform heaps that often show complex structure . The physical forms are cross-classified by the altitude levels to produce ten basic genus-types , most of which can be divided into species , and subdivided into varieties .   Two cirriform clouds that form higher up in the stratosphere and mesosphere have common names for their main types , but are sub-classified alpha-numerically . They are relatively uncommon and are mostly seen in the polar regions of Earth . Clouds have been observed in the atmospheres of other planets and moons in the Solar System and beyond . However , due to their different temperature characteristics , they are often composed of other substances such as methane , ammonia , and sulfuric acid as well as water .   Homospheric types determined by cross-classification of forms and levels .   '' Homospheric types include the ten tropospheric genera and two additional major types above the troposphere . The cumulus genus includes three variants as defined by vertical size .


Cloud feedback

Cloud feedback is the coupling between cloudiness and surface air temperature where a surface air temperature change leads to a change in clouds , which could then amplify or diminish the initial temperature perturbation . Cloud feedbacks can affect the magnitude of internally generated climate variability or they can affect the magnitude of climate change resulting from external radiative forcings .   Global warming is expected to change the distribution and type of clouds . Seen from below , clouds emit infrared radiation back to the surface , and so exert a warming effect ; seen from above , clouds reflect sunlight and emit infrared radiation to space , and so exert a cooling effect . Cloud representations vary among global climate models , and small changes in cloud cover have a large impact on the climate . Differences in planetary boundary layer cloud modeling schemes can lead to large differences in derived values of climate sensitivity . A model that decreases boundary layer clouds in response to global warming has a climate sensitivity twice that of a model that does not include this feedback . However , satellite data show that cloud optical thickness actually increases with increasing temperature . Whether the net effect is warming or cooling depends on details such as the type and altitude of the cloud ; details that are difficult to represent in climate models .


Cloud forest

A cloud forest , also called a fog forest , is a generally tropical or subtropical , evergreen , montane , moist forest characterized by a persistent , frequent or seasonal low-level cloud cover , usually at the canopy level , formally described in the International Cloud Atlas ( 2017 ) as silvagenitus . Cloud forests often exhibit an abundance of mosses covering the ground and vegetation , in which case they are also referred to as mossy forests . Mossy forests usually develop on the saddles of mountains , where moisture introduced by settling clouds is more effectively retained .


Clouds and the Earth's Radiant Energy System

Clouds and the Earth 's Radiant Energy System ( CERES ) is NASA climatological experiment from Earth orbit .  The CERES are scientific satellite instruments , part of the NASA 's Earth Observing System  ( EOS ) , designed to measure both solar-reflected and Earth-emitted radiation from the top of the atmosphere ( TOA ) to the  Earth 's surface . Cloud properties are determined using simultaneous measurements by other EOS instruments such as the  Moderate Resolution Imaging Spectroradiometer ( MODIS ) . Results from the CERES and other NASA missions , such as the Earth Radiation Budget Experiment ( ERBE ) ,  could lead to a better understanding of the role of clouds and the energy cycle in global climate change .


Coal

Coal is a combustible black or brownish-black sedimentary rock usually occurring in rock strata in layers or veins called coal beds or coal seams . The harder forms , such as anthracite coal , can be regarded as metamorphic rock because of later exposure to elevated temperature and pressure . Coal is composed primarily of carbon , along with variable quantities of other elements , chiefly hydrogen , sulfur , oxygen , and nitrogen . A fossil fuel , coal forms when dead plant matter is converted into peat , which in turn is converted into lignite , then sub-bituminous coal , after that bituminous coal , and lastly anthracite . This involves biological and geological processes that take place over time .   Throughout human history , coal has been used as an energy resource , primarily burned for the production of electricity and heat , and is also used for industrial purposes , such as refining metals . Coal is the largest source of energy for the generation of electricity worldwide , as well as one of the largest worldwide anthropogenic sources of carbon dioxide releases . The extraction of coal , its use in energy production and its byproducts are all associated with environmental and health effects including climate change .   Coal is extracted from the ground by coal mining . Since 1983 , the world 's top coal producer has been China . In 2015 China produced 3,747 million tonnes of coal -- 47.7 % of 7,861 million tonnes world coal production . In 2015 other large producers were United States ( 813 million tonnes ) , India ( 678 ) , European Union ( 539 ) and Australia ( 503 ) . In 2010 the largest exporters were Australia with 328 million tonnes ( 27.1 % of world coal export ) and Indonesia with 316 million tonnes ( 26.1 % ) , while the largest importers were Japan with 207 million tonnes ( 17.5 % of world coal import ) , China with 195 million tonnes ( 16.6 % ) and South Korea with 126 million tonnes ( 10.7 % ) .


Coal mining

Coal mining is the process of extracting coal from the ground . Coal is valued for its energy content , and , since the 1880s , has been widely used to generate electricity . Steel and cement industries use coal as a fuel for extraction of iron from iron ore and for cement production . In the United Kingdom and South Africa a coal mine and its structures are a colliery ; a coal mine a pit ; the above-ground structures the pit head . In Australia , `` colliery '' generally refers to an underground coal mine . In the United States `` colliery '' has been used to describe a coal mine operation but nowadays the word is not commonly used .   Coal mining has had many developments over the recent years , from the early days of men tunnelling , digging and manually extracting the coal on carts , to large open cut and long wall mines . Mining at this scale requires the use of draglines , trucks , conveyors , hydraulic jacks and shearers .


Coal pollution mitigation

Coal pollution mitigation , often referred to by the public relations term clean coal , is a series of systems and technologies that seek to mitigate the pollution and other environmental effects normally associated with the burning ( though not the mining or processing ) of coal , which is widely regarded as the dirtiest of the common fuels for industrial processes and power generation . The preferred industry term `` clean coal '' has been described as `` Orwellian '' , an oxymoron , and a myth .   Approaches attempt to mitigate emissions of carbon dioxide ( CO2 ) and other greenhouse gases , and radioactive materials , that arise from the use of coal , mainly for electrical power generation , using various technologies . Historical efforts to reduce coal pollution focused on flue-gas desulfurization starting in the 1850s and clean burn technologies . More recent developments include carbon capture and storage , which pumps and stores CO2 emissions underground , and integrated gasification combined cycle ( IGCC ) involve coal gasification , which provides a basis for increased efficiency and lower cost in capturing CO2 emissions .   There are seven technologies deployed or proposed for deployment in the United States :  carbon capture and storage ( CCS ) ,  flue-gas desulfurization ,  fluidized-bed combustion ,  integrated gasification combined cycle ( IGCC ) ,  low nitrogen oxide burners ,  selective catalytic reduction ( SCR ) , and  electrostatic precipitators .  Of the 22 demonstration projects funded by the U.S. Department of Energy since 2003 , none are in operation as of February 2017 , having been abandoned or delayed due to capital budget overruns or discontinued because of excessive operating expenses .


Coastal fish

Coastal fish , also called inshore fish or neritic fish , inhabit the sea between the shoreline and the edge of the continental shelf . Since the continental shelf is usually less than 200 metres deep , it follows that pelagic coastal fish are generally epipelagic fish , inhabiting the sunlit epipelagic zone . Coastal fish can be contrasted with oceanic fish or offshore fish , which inhabit the deep seas beyond the continental shelves .   Coastal fish are the most abundant in the world . They can be found in tidal pools , fjords and estuaries , near sandy shores and rocky coastlines , around coral reefs and on or above the continental shelf . Coastal fish include forage fish and the predator fish that feed on them . Forage fish thrive in inshore waters where high productivity results from upwelling and shoreline run off of nutrients . Some are partial residents that spawn in streams , estuaries and bays , but most complete their life cycles in the zone .


Cold War

The Cold War was a state of geopolitical tension after World War II between powers in the Eastern Bloc ( the Soviet Union and its satellite states ) and powers in the Western Bloc ( the United States , its NATO allies and others ) . Historians do not fully agree on the dates , but a common timeframe is the period between 1947 , the year the Truman Doctrine ( a U.S. foreign policy pledging to aid nations threatened by Soviet expansionism ) was announced , and 1991 , the year the Soviet Union collapsed .   The term `` cold '' is used because there was no large-scale fighting directly between the two sides involved in the conflict , although there were major regional wars , known as proxy wars , supported by the two sides . The Cold War split the temporary wartime alliance against Nazi Germany , leaving the Soviet Union and the United States as two superpowers with profound economic and political differences . The USSR was a Marxist -- Leninist state led by its Communist Party of the Soviet Union , who in turn were led by a leader , with different titles over time , and a small committee called the Politburo . The Party controlled the press , the military , the economy and many organization . It also controlled the other states in the Eastern Bloc , and funded Communist parties around the world , sometimes in competition with Communist China , particularly following the Sino-Soviet split of the 1960s . In opposition stood the West , staunchly democratic and capitalist with a free press and independent organizations . A small neutral bloc arose with the Non-Aligned Movement ; it sought good relations with both sides . The two superpowers never engaged directly in full-scale armed combat , but they were heavily armed in preparation for a possible all-out nuclear world war . Each side had a nuclear strategy that discouraged an attack by the other side , on the basis that such an attack would lead to the total destruction of the attacker : the doctrine of mutually assured destruction ( MAD ) . Aside from the development of the two sides ' nuclear arsenals , and their deployment of conventional military forces , the struggle for dominance was expressed via proxy wars around the globe , psychological warfare , massive propaganda campaigns and espionage , rivalry at sports events , and technological competitions such as the Space Race .   The first phase of the Cold War began in the first two years after the end of the Second World War in 1945 . The USSR consolidated its control over the states of the Eastern Bloc , while the United States began a strategy of global containment to challenge Soviet power , extending military and financial aid to the countries of Western Europe ( for example , supporting the anti-communist side in the Greek Civil War ) and creating the NATO alliance . The Berlin Blockade ( 1948 -- 49 ) was the first major crisis of the Cold War . With the victory of the communist side in the Chinese Civil War and the outbreak of the Korean War ( 1950 -- 53 ) , the conflict expanded . The USSR and USA competed for influence in Latin America , and the decolonizing states of Africa and Asia . Meanwhile , the Hungarian Revolution of 1956 was stopped by the Soviets . The expansion and escalation sparked more crises , such as the Suez Crisis ( 1956 ) , the Berlin Crisis of 1961 , and the Cuban Missile Crisis of 1962 . Following the Cuban Missile Crisis , a new phase began that saw the Sino-Soviet split complicate relations within the communist sphere , while US allies , particularly France , demonstrated greater independence of action . The USSR crushed the 1968 Prague Spring liberalization program in Czechoslovakia , and the Vietnam War ( 1955 -- 75 ) ended with the defeat of the US-backed Republic of Vietnam , prompting further adjustments .   By the 1970s , both sides had become interested in making accommodations in order to create a more stable and predictable international system , inaugurating a period of détente that saw Strategic Arms Limitation Talks and the US opening relations with the People 's Republic of China as a strategic counterweight to the Soviet Union . Détente collapsed at the end of the decade with the beginning of the Soviet -- Afghan War in 1979 . The early 1980s were another period of elevated tension , with the Soviet downing of Korean Air Lines Flight 007 ( 1983 ) , and the `` Able Archer '' NATO military exercises ( 1983 ) . The United States increased diplomatic , military , and economic pressures on the Soviet Union , at a time when the communist state was already suffering from economic stagnation . In the mid-1980s , the new Soviet leader Mikhail Gorbachev introduced the liberalizing reforms of perestroika ( `` reorganization '' , 1987 ) and glasnost ( `` openness '' , c. 1985 ) and ended Soviet involvement in Afghanistan . Pressures for national independence grew stronger in Eastern Europe , especially Poland . Gorbachev meanwhile refused to use Soviet troops to bolster the faltering Warsaw Pact regimes as had occurred in the past . The result in 1989 was a wave of revolutions that peacefully ( with the exception of the Romanian Revolution ) overthrew all of the communist regimes of Central and Eastern Europe . The Communist Party of the Soviet Union itself lost control and was banned following an abortive coup attempt in August 1991 . This in turn led to the formal dissolution of the USSR in December 1991 and the collapse of communist regimes in other countries such as Mongolia , Cambodia and South Yemen . The United States remained as the world 's only superpower .   The Cold War and its events have left a significant legacy . It is often referred to in popular culture , especially in media featuring themes of espionage ( e.g. the internationally successful James Bond movie franchise ) and the threat of nuclear warfare .


Cold wave

A cold wave ( known in some regions as a cold snap ) is a weather phenomenon that is distinguished by a cooling of the air . Specifically , as used by the U.S. National Weather Service , a cold wave is a rapid fall in temperature within a 24-hour period requiring substantially increased protection to agriculture , industry , commerce , and social activities . The precise criterion for a cold wave is determined by the rate at which the temperature falls , and the minimum to which it falls . This minimum temperature is dependent on the geographical region and time of year .   In the United States , a cold spell is defined as the national average high temperature dropping below 20 F.


Colonization of Mars

Mars is the focus of much scientific study about possible human colonization . Its surface conditions and the presence of water on Mars make it arguably the most hospitable of the planets in the Solar System , other than Earth . Mars requires less energy per unit mass ( delta-v ) to reach from Earth than any planet except Venus .   Permanent human habitation on a planetary body other than the Earth is one of science fiction 's most prevalent themes . As technology has advanced , and concerns about the future of humanity on Earth have increased , the argument that space colonization is an achievable and worthwhile goal has gained momentum . Other reasons for colonizing space include economic interests , long-term scientific research best carried out by humans as opposed to robotic probes , and sheer curiosity .   One of Elon Musk 's stated goals through his company SpaceX is to make such colonization possible by providing transport , and to `` help humanity establish a permanent , self-sustaining colony on -LSB- Mars -RSB- within the next 50 to 100 years '' .


Colonization of the Moon

The colonization of the Moon is a proposed establishment of permanent human communities or robotic industries on the Moon .   Discovery of lunar water at the lunar poles by Chandrayaan-1 has renewed interest in the Moon . Polar colonies could also avoid the problem of long lunar nights -- about 354 hours , a little more than two weeks -- and take advantage of the Sun continuously , at least during the local summer ( there is no data for the winter yet ) .   Permanent human habitation on a planetary body other than the Earth is one of science fiction 's most prevalent themes . As technology has advanced , and concerns about the future of humanity on Earth have increased , the argument that space colonization is an achievable and worthwhile goal has gained momentum . Because of its proximity to Earth , the Moon has been seen as the most obvious natural expansion after Earth . There are also various projects in near future by space tourism startup companies for tourism on the Moon .


Colorado River

The Colorado River is one of the principal rivers of the Southwestern United States and northern Mexico ( the other being the Rio Grande ) . The 1450 mi river drains an expansive , arid watershed that encompasses parts of seven U.S. and two Mexican states . Starting in the central Rocky Mountains in the U.S. , the river flows generally southwest across the Colorado Plateau and through the Grand Canyon before reaching Lake Mead on the Arizona -- Nevada border , where it turns south toward the international border . After entering Mexico , the Colorado approaches the mostly dry Colorado River Delta at the tip of the Gulf of California between Baja California and Sonora .   Known for its dramatic canyons , whitewater rapids , and eleven U.S. National Parks , the Colorado River system is a vital source of water for 40 million people in southwestern North America . The river and its tributaries are controlled by an extensive system of dams , reservoirs , and aqueducts , which in most years divert its entire flow for agricultural irrigation and domestic water supply . Its large flow and steep gradient are used for generating hydroelectric power , and its major dams regulate peaking power demands in much of the Intermountain West . Intensive water consumption has dried up the lower 100 mi of the river , which has rarely reached the sea since the 1960s .   Beginning with small bands of nomadic hunter-gatherers , Native Americans have inhabited the Colorado River basin for at least 8,000 years . Between 2,000 and 1,000 years ago , the river and its tributaries fostered large agricultural civilizations -- some of the most sophisticated indigenous cultures in North America -- which eventually faded due to a combination of severe drought and poor land use practices . Most native peoples that inhabit the basin today are descended from other groups that settled in the region beginning about 1,000 years ago . Europeans first entered the Colorado Basin in the 16th century , when explorers from Spain began mapping and claiming the area , which later became part of Mexico upon its independence in 1821 . Early contact between Europeans and Native Americans was generally limited to the fur trade in the headwaters and sporadic trade interactions along the lower river .   After most of the Colorado River basin became part of the U.S. in 1846 , the bulk of the river 's course was still the subject of myths and speculation . Several expeditions charted the Colorado in the mid-19th century -- one of which , led by John Wesley Powell , was the first to run the rapids of the Grand Canyon . American explorers collected valuable information that was later used to develop the river for navigation and water supply . Large-scale settlement of the lower basin began in the mid - to late-19th century , with steamboats providing transportation from the Gulf of California to landings along the river that linked to wagon roads to the interior . Lesser numbers settled in the upper basin , which was the scene of major gold strikes in the 1860s and 1870s .   Large engineering works began around the start of the 20th century , with major guidelines established in a series of international and U.S. interstate treaties known as the `` Law of the River '' . The U.S. federal government was the main driving force behind the construction of dams and aqueducts , although many state and local water agencies were also involved . Most of the major dams were built between 1910 and 1970 ; the system keystone , Hoover Dam , was completed in 1935 . The Colorado is now considered among the most controlled and litigated rivers in the world , with every drop of its water fully allocated .   The environmental movement in the American Southwest has opposed the damming and diversion of the Colorado River system because of detrimental effects on the ecology and natural beauty of the river and its tributaries . During the construction of Glen Canyon Dam , environmental organizations vowed to block any further development of the river , and a number of later dam and aqueduct proposals were defeated by citizen opposition . As demands for Colorado River water continue to rise , the level of human development and control of the river continues to generate controversy .


Comet

A comet is an icy small Solar System body that , when passing close to the Sun , warms and begins to release gasses , a process called outgassing . This produces a visible atmosphere or coma , and sometimes also a tail . These phenomena are due to the effects of solar radiation and the solar wind acting upon the nucleus of the comet . Comet nuclei range from a few hundred metres to tens of kilometres across and are composed of loose collections of ice , dust , and small rocky particles . The coma may be up to 15 times the Earth 's diameter , while the tail may stretch one astronomical unit . If sufficiently bright , a comet may be seen from the Earth without the aid of a telescope and may subtend an arc of 30 ° ( 60 Moons ) across the sky . Comets have been observed and recorded since ancient times by many cultures .   Comets usually have highly eccentric elliptical orbits , and they have a wide range of orbital periods , ranging from several years to potentially several millions of years . Short-period comets originate in the Kuiper belt or its associated scattered disc , which lie beyond the orbit of Neptune . Long-period comets are thought to originate in the Oort cloud , a spherical cloud of icy bodies extending from outside the Kuiper belt to halfway to the nearest star . Long-period comets are set in motion towards the Sun from the Oort cloud by gravitational perturbations caused by passing stars and the galactic tide . Hyperbolic comets may pass once through the inner Solar System before being flung to interstellar space . The appearance of a comet is called an apparition .   Comets are distinguished from asteroids by the presence of an extended , gravitationally unbound atmosphere surrounding their central nucleus . This atmosphere has parts termed the coma ( the central part immediately surrounding the nucleus ) and the tail ( a typically linear section consisting of dust or gas blown out from the coma by the Sun 's light pressure or outstreaming solar wind plasma ) . However , extinct comets that have passed close to the Sun many times have lost nearly all of their volatile ices and dust and may come to resemble small asteroids . Asteroids are thought to have a different origin from comets , having formed inside the orbit of Jupiter rather than in the outer Solar System . The discovery of main-belt comets and active centaur minor planets has blurred the distinction between asteroids and comets .   there are 5,253 known comets , a number that is steadily increasing as they are discovered . However , this represents only a tiny fraction of the total potential comet population , as the reservoir of comet-like bodies in the outer Solar System ( in the Oort cloud ) is estimated to be one trillion . Roughly one comet per year is visible to the naked eye , though many of those are faint and unspectacular . Particularly bright examples are called `` Great Comets '' . Comets have been visited by unmanned probes such as the European Space Agency 's Rosetta , which became the first ever to land a robotic spacecraft on a comet , and NASA 's Deep Impact , which blasted a crater on Comet Tempel 1 to study its interior .


Common octopus

The common octopus ( Octopus vulgaris ) is a mollusc belonging to the class Cephalopoda . Octopus vulgaris is the most studied of all octopus species .


Communications satellite

A communications satellite is an artificial satellite that relays and amplifies radio telecommunications signals via a transponder ; it creates a communication channel between a source transmitter and a receiver at different locations on Earth . Communications satellites are used for television , telephone , radio , internet , and military applications . There are over 2,000 communications satellites in Earth 's orbit , used by both private and government organizations .   Wireless communication uses electromagnetic waves to carry signals . These waves require line-of-sight , and are thus obstructed by the curvature of the Earth . The purpose of communications satellites is to relay the signal around the curve of the Earth allowing communication between widely separated points .  Communications satellites use a wide range of radio and microwave frequencies . To avoid signal interference , international organizations have regulations for which frequency ranges or `` bands '' certain organizations are allowed to use . This allocation of bands minimizes the risk of signal interference .


Complex system

A complex system is a system composed of many components which may interact with each other . In many cases it is useful to represent such a system as a network where the nodes represent the components and the links their interactions . Examples of complex systems are Earth 's global climate , organisms , the human brain , social and economic organizations ( like cities ) , an ecosystem , a living cell , and ultimately the entire universe .


Computer

A computer is a device that can be instructed to carry out an arbitrary set of arithmetic or logical operations automatically . The ability of computers to follow generalized sequences of operations , called programs , enable them to perform a wide range of tasks .   Such computers are used as control systems for a very wide variety of industrial and consumer devices . This includes simple special purpose devices like microwave ovens and remote controls , factory devices such as industrial robots and computer assisted design , but also in general purpose devices like personal computers and mobile devices such as smartphones . The Internet is run on computers and it connects millions of other computers .   Since ancient times , simple manual devices like the abacus aided people in doing calculations . Early in the Industrial Revolution , some mechanical devices were built to automate long tedious tasks , such as guiding patterns for looms . More sophisticated electrical machines did specialized analog calculations in the early 20th century . The first digital electronic calculating machines were developed during World War II . The speed , power , and versatility of computers has increased continuously and dramatically since then .   Conventionally , a modern computer consists of at least one processing element , typically a central processing unit ( CPU ) , and some form of memory . The processing element carries out arithmetic and logical operations , and a sequencing and control unit can change the order of operations in response to stored information . Peripheral devices include input devices ( keyboards , mice , joystick , etc. ) , output devices ( monitor screens , printers , etc. ) , and input/output devices that perform both functions ( e.g. , the 2000s-era touchscreen ) . Peripheral devices allow information to be retrieved from an external source and they enable the result of operations to be saved and retrieved .


Computer science

Computer science deals with the theoretical foundations of information and computation , together with practical techniques for the implementation and application of these foundations .   Computer science is the study of the theory , experimentation , and engineering that form the basis for the design and use of computers . It is the scientific and practical approach to computation and its applications and the systematic study of the feasibility , structure , expression , and mechanization of the methodical procedures ( or algorithms ) that underlie the acquisition , representation , processing , storage , communication of , and access to information . An alternate , more succinct definition of computer science is the study of automating algorithmic processes that scale . A computer scientist specializes in the theory of computation and the design of computational systems .   Its fields can be divided into a variety of theoretical and practical disciplines . Some fields , such as computational complexity theory ( which explores the fundamental properties of computational and intractable problems ) , are highly abstract , while fields such as computer graphics emphasize real-world visual applications . Other fields still focus on challenges in implementing computation . For example , programming language theory considers various approaches to the description of computation , while the study of computer programming itself investigates various aspects of the use of programming language and complex systems . Human -- computer interaction considers the challenges in making computers and computations useful , usable , and universally accessible to humans .