Global storm activity of 2010

The global storm activity of 2010 includes major meteorological events in the Earth 's atmosphere during the year , including winter storms ( blizzards , ice storms , European windstorms ) , hailstorms , out of season monsoon rain storms , extratropical cyclones , gales , microbursts , flooding , rainstorms , tropical cyclones , and other severe weather events .   The thunderstorm season for the Northern Hemisphere began this time of year , beginning on March 1 , and ending on August 31 .


Global temperature record

The global temperature record shows the fluctuations of the temperature of the atmosphere and the oceans through various spans of time.  The most detailed information exists since 1850, when methodical thermometer-based records began.  There are numerous estimates of temperatures since the end of the Pleistocene glaciation, particularly during the current Holocene epoch.  Older time periods are studied by paleoclimatology.


Global warming

Global warming , also referred to as climate change , is the observed century-scale rise in the average temperature of the Earth 's climate system and its related effects . Multiple lines of scientific evidence show that the climate system is warming . Many of the observed changes since the 1950s are unprecedented in the instrumental temperature record which extends back to the mid 19th century , and in paleoclimate proxy records over thousands of years .   In 2013 , the Intergovernmental Panel on Climate Change ( IPCC ) Fifth Assessment Report concluded that `` It is extremely likely that human influence has been the dominant cause of the observed warming since the mid-20th century . '' The largest human influence has been emission of greenhouse gases such as carbon dioxide , methane and nitrous oxide . Climate model projections summarized in the report indicated that during the 21st century the global surface temperature is likely to rise a further 0.3 to for their lowest emissions scenario and 2.6 to for the highest emissions scenario . These findings have been recognized by the national science academies of the major industrialized nations and are not disputed by any scientific body of national or international standing .   Future climate change and associated impacts will differ from region to region around the globe . Anticipated effects include warming global temperature , rising sea levels , changing precipitation , and expansion of deserts in the subtropics . Warming is expected to be greater over land than over the oceans and greatest in the Arctic , with the continuing retreat of glaciers , permafrost and sea ice . Other likely changes include more frequent extreme weather events including heat waves , droughts , heavy rainfall with floods and heavy snowfall ; ocean acidification ; and species extinctions due to shifting temperature regimes . Effects significant to humans include the threat to food security from decreasing crop yields and the abandonment of populated areas due to rising sea levels . Because the climate system has a large `` inertia '' and greenhouse gases will stay in the atmosphere for a long time , many of these effects will not only exist for decades or centuries , but will persist for tens of thousands of years .   Possible societal responses to global warming include mitigation by emissions reduction , adaptation to its effects , building systems resilient to its effects , and possible future climate engineering . Most countries are parties to the United Nations Framework Convention on Climate Change ( UNFCCC ) ,  whose ultimate objective is to prevent dangerous anthropogenic climate change . Parties to the UNFCCC have agreed that deep cuts in emissions are required and that global warming should be limited to well below 2.0 C-change relative to pre-industrial levels , with efforts made to limit warming to 1.5 C-change .   Public reactions to global warming and concern about its effects are also increasing . A global 2015 Pew Research Center report showed a median of 54 % consider it `` a very serious problem '' . There are significant regional differences , with Americans and Chinese ( whose economies are responsible for the greatest annual CO2 emissions ) among the least concerned .


Global warming conspiracy theory

A global warming conspiracy theory invokes claims that scientific consensus on global warming is based on conspiracies to produce false data or suppress dissent . It is one of a number of tactics used in climate change denial to legitimize political controversy disputing this consensus .  Global warming conspiracy theorists typically allege that , through worldwide acts of professional and criminal misconduct , the science behind global warming has been invented or distorted for ideological or financial reasons , or both .


Global warming controversy

The global warming controversy concerns the public debate over whether global warming is occurring , how much has occurred in modern times , what has caused it , what its effects will be , whether any action should be taken to curb it , and if so what that action should be . In the scientific literature , there is a strong consensus that global surface temperatures have increased in recent decades and that the trend is caused by human-induced emissions of greenhouse gases . No scientific body of national or international standing disagrees with this view , though a few organizations with members in extractive industries hold non-committal positions . Disputes over the key scientific facts of global warming are more prevalent in the media than in the scientific literature , where such issues are treated as resolved , and such disputes are more prevalent in the United States than globally .   Political and popular debate concerning the existence and cause of climate change includes the reasons for the increase seen in the instrumental temperature record , whether the warming trend exceeds normal climatic variations , and whether human activities have contributed significantly to it . Scientists have resolved these questions decisively in favour of the view that the current warming trend exists and is ongoing , that human activity is the cause , and that it is without precedent in at least 2000 years . Public disputes that also reflect scientific debate include estimates of how responsive the climate system might be to any given level of greenhouse gases ( climate sensitivity ) , how global climate change will play out at local and regional scales , and what the consequences of global warming will be .   Global warming remains an issue of widespread political debate , often split along party political lines , especially in the United States . Many of the issues that are settled within the scientific community , such as human responsibility for global warming , remain the subject of politically or economically motivated attempts to downplay , dismiss or deny them -- an ideological phenomenon categorised by academics and scientists as climate change denial . The sources of funding for those involved with climate science -- both supporting and opposing mainstream scientific positions -- have been questioned by both sides . There are debates about the best policy responses to the science , their cost-effectiveness and their urgency . Climate scientists , especially in the United States , have reported official and oil-industry pressure to censor or suppress their work and hide scientific data , with directives not to discuss the subject in public communications . Legal cases regarding global warming , its effects , and measures to reduce it have reached American courts . The fossil fuels lobby has been identified as overtly or covertly supporting efforts to undermine or discredit the scientific consensus on global warming .


Global warming hiatus

A global warming hiatus , also sometimes referred to as a global warming pause or a global warming slowdown , is a period of relatively little change in globally averaged surface temperatures . In the current episode of global warming many such 15-year periods appear in the surface temperature record , along with robust evidence of the long-term warming trend ; climate is classically averaged over 30-year periods .   Publicity has surrounded claims of a global warming hiatus during the period 1998 -- 2013 . The exceptionally warm El Niño year of 1998 was an outlier from the continuing temperature trend , and so subsequent annual temperatures gave the appearance of a hiatus : by January 2006 , it appeared to some that global warming had stopped or paused . A 2009 study showed that decades without warming were not exceptional , and in 2011 a study showed that if allowances were made for known variability , the rising temperature trend continued unabated . There was increased public interest in 2013 in the run-up to publication of the IPCC Fifth Assessment Report , and despite concerns that a 15-year period was too short to determine a meaningful trend , the IPCC included a section on a hiatus , which it defined as a much smaller increasing linear trend over the 15 years from 1998 to 2012 , than over the 60 years from 1951 to 2012 . Various studies examined possible causes of the short-term slowdown . Even though the overall climate system has continued to accumulate energy due to Earth 's positive energy budget , the available temperature readings at the Earth 's surface indicate slower rates of increase in surface warming than in the prior decade . Since measurements at the top of the atmosphere show that Earth is receiving more energy than it is radiating back into space , the retained energy should be producing warming in the Earth 's climate system .   Research reported in July 2015 on an updated NOAA dataset casts doubt on the existence of a hiatus , and it finds no indication of a slowdown even in earlier years . Scientists working on other datasets welcomed this study , though they have expressed the view that the recent warming trend was less than in previous periods of the same length . Subsequently , a detailed study supports the conclusion that warming is continuing , but it also find there was less warming between 2001 and 2010 than climate models had predicted , and that this slowdown might be attributed to short-term variations in the Pacific decadal oscillation ( PDO ) , which was negative during that period . Another review finds `` no substantive evidence '' of a pause in global warming . A statistical study of global temperature data since 1970 concludes that the term ` hiatus ' or ` pause ' is not justified .   Independent of these discussions about data and measurements for earlier years , 2015 turned out to be much warmer than any of the earlier years , already before El Niño conditions started . The warmth of 2015 largely ended any remaining scientific credibility of claims that the supposed `` hiatus '' since 1998 had any significance for the long-term warming trend . In January 2017 , a study published in the journal Science Advances cast further doubt on the existence of a recent pause , with more evidence that ocean temperatures have been underestimated . An April 2017 study found the data consistent with a steady warming trend globally since the 1970s , with fluctuations within the expected range of short term variability .


Global warming in Antarctica

The effects of global warming in Antarctica may include rising temperatures and increasing snow melt .


Global warming potential

Global warming potential ( GWP ) is a relative measure of how much heat a greenhouse gas traps in the atmosphere . It compares the amount of heat trapped by a certain mass of the gas in question to the amount of heat trapped by a similar mass of carbon dioxide . A GWP is calculated over a specific time interval , commonly 20 , 100 , or 500 years . GWP is expressed as a factor of carbon dioxide ( whose GWP is standardized to 1 ) . In the Fifth Assessment Report of the Intergovernmental Panel on Climate Change , methane has a lifetime of 12.4 years and with climate-carbon feedbacks a global warming potential of 86 over 20 years and 34 over 100 years in response to emissions . User related choices such as the time horizon can greatly affect the numerical values obtained for carbon dioxide equivalents . For a change in time horizon from 20 to 100 years , the GWP for methane decreases by a factor of approximately 2.5 .  The substances subject to restrictions under the Kyoto protocol either are rapidly increasing their concentrations in Earth 's atmosphere or have a large GWP .   The GWP depends on the following factors :  the absorption of infrared radiation by a given species  the spectral location of its absorbing wavelengths  the atmospheric lifetime of the species  Thus , a high GWP correlates with a large infrared absorption and a long atmospheric lifetime . The dependence of GWP on the wavelength of absorption is more complicated . Even if a gas absorbs radiation efficiently at a certain wavelength , this may not affect its GWP much if the atmosphere already absorbs most radiation at that wavelength . A gas has the most effect if it absorbs in a `` window '' of wavelengths where the atmosphere is fairly transparent . The dependence of GWP as a function of wavelength has been found empirically and published as a graph .   Because the GWP of a greenhouse gas depends directly on its infrared spectrum , the use of infrared spectroscopy to study greenhouse gases is centrally important in the effort to understand the impact of human activities on global climate change .


Glossary of fishery terms

This is a glossary of terms used in fisheries , fisheries management and fisheries science .


Glossary of geography terms

Geographical terms are words or phrases which describe and identify natural phenomenons , geographical locations , spatial dimension and natural resources . Geographical terms are classified according to their functions , such as description , explanation , analysing , evaluating and integrating .   This is a list of geographical terms in alphabetical order .


Gondwana

In paleogeography , Gondwana ( -LSB- pronɡɒndˈwɑːnə -RSB- ) , also Gondwanaland , is the name given to an ancient supercontinent . It is believed to have sutured about , joining East Gondwana to West Gondwana . Gondwana formed prior to Pangaea , and later became part of it .   Around , Gondwana and Laurasia joined together to form the supercontinent Pangaea , which existed until approximately . Gondwana then separated from Laurasia ( the mid-Mesozoic era ) in the breakup of Pangaea , drifting farther south after the split . Gondwana itself then also broke apart .   Gondwana included most of the landmasses in today 's Southern Hemisphere , including Antarctica , South America , Africa , Madagascar , and the Australian continent , as well as the Arabian Peninsula and the Indian subcontinent , which have now moved entirely into the Northern Hemisphere .   The continent of Gondwana was named by Austrian scientist Eduard Suess , after the Gondwana region of central northern India which is derived from Sanskrit for `` forest of the Gonds '' . The name had been previously used in a geological context , first by H.B. Medlicott in 1872 , from which the Gondwana sedimentary sequences ( Permian-Triassic ) are also described .   The adjective `` Gondwanan '' is in common use in biogeography when referring to patterns of distribution of living organisms , typically when the organisms are restricted to two or more of the now-discontinuous regions that were once part of Gondwana , including the Antarctic flora . For example , the plant family Proteaceae , known only from southern South America , South Africa , Australia , and New Zealand , is considered to have a `` Gondwanan distribution '' . This pattern is often considered to indicate an archaic , or relict , lineage .


Google

Google is an American multinational technology company specializing in Internet-related services and products . These include online advertising technologies , search , cloud computing , software , and hardware . Google was founded in 1998 by Larry Page and Sergey Brin while they were Ph.D. students at Stanford University , in California . Together , they own about 14 percent of its shares , and control 56 percent of the stockholder voting power through supervoting stock . They incorporated Google as a privately held company on September 4 , 1998 . An initial public offering ( IPO ) took place on August 19 , 2004 , and Google moved to its new headquarters in Mountain View , California , nicknamed the Googleplex . In August 2015 , Google announced plans to reorganize its various interests as a conglomerate called Alphabet Inc. . Google , Alphabet 's leading subsidiary , will continue to be the umbrella company for Alphabet 's Internet interests . Upon completion of the restructure , Sundar Pichai became CEO of Google , replacing Larry Page , who became CEO of Alphabet .   Rapid growth since incorporation has triggered a chain of products , acquisitions , and partnerships beyond Google 's core search engine ( Google Search ) . It offers services designed for work and productivity ( Google Docs , Sheets and Slides ) , email ( Gmail/Inbox ) , scheduling and time management ( Google Calendar ) , cloud storage ( Google Drive ) , social networking ( Google + ) , instant messaging and video chat ( Google Allo/Duo/Hangouts ) , language translation ( Google Translate ) , mapping and turn-by-turn navigation ( Google Maps ) , video sharing ( YouTube ) , notetaking ( Google Keep ) , and photo organizing and editing ( Google Photos ) . The company leads the development of the Android mobile operating system , the Google Chrome web browser , and Chrome OS , a lightweight operating system based on the Chrome browser . Google has moved increasingly into hardware ; from 2010 to 2015 , it partnered with major electronics manufacturers in the production of its Nexus devices , and in October 2016 , it released multiple hardware products ( including the Google Pixel smartphone , Home smart speaker , Wifi mesh wireless router , and Daydream View virtual reality headset ) . The new hardware chief , Rick Osterloh , stated : `` a lot of the innovation that we want to do now ends up requiring controlling the end-to-end user experience '' . Google has also experimented with becoming an Internet carrier . In February 2010 , it announced Google Fiber , a fiber-optic infrastructure that was installed in Kansas City ; in April 2015 , it launched Project Fi in the United States , combining Wi-Fi and cellular networks from different providers ; and in 2016 , it announced the Google Station initiative to make public Wi-Fi around the world , which had already been deployed in India .   Alexa , a company that monitors commercial web traffic , lists Google.com as the most visited website in the world . Several other Google services also figure in the top 100 most visited websites , including YouTube and Blogger . Google has been the second most valuable brand in the world for 4 consecutive years , but has received significant criticism involving issues such as privacy concerns , tax avoidance , antitrust , censorship , and search neutrality . Google 's mission statement , from the outset , was `` to organize the world 's information and make it universally accessible and useful '' , and its unofficial slogan was `` Do n't be evil '' . In October 2015 , the motto was replaced in the Alphabet corporate code of conduct by the phrase `` Do the right thing '' .


Google Scholar

Google Scholar is a freely accessible web search engine that indexes the full text or metadata of scholarly literature across an array of publishing formats and disciplines . Released in beta in November 2004 , the Google Scholar index includes most peer-reviewed online academic journals and books , conference papers , theses and dissertations , preprints , abstracts , technical reports , and other scholarly literature , including court opinions and patents . While Google does not publish the size of Google Scholar 's database , third-party researchers estimated it to contain roughly 160 million documents as of May 2014 and an earlier statistical estimate published in PLOS ONE using a Mark and recapture method estimated approximately 80-90 % coverage of all articles published in English with an estimate of 100 million . This estimate also determined how many documents were freely available on the web .   Google Scholar is similar in function to the freely available CiteSeerX and getCITED . It also resembles the subscription-based tools , Elsevier 's Scopus and Thomson Reuters ' Web of Science .


Gordon Brown

James Gordon Brown ( born 20 February 1951 ) is a British politician who was Prime Minister of the United Kingdom and Leader of the Labour Party from 2007 to 2010 . He served as Chancellor of the Exchequer in the Blair Government from 1997 to 2007 . Brown was a Member of Parliament ( MP ) from 1983 to 2015 , first for Dunfermline East and later for Kirkcaldy and Cowdenbeath .   A doctoral graduate of the University of Edinburgh , Brown spent his early career working as both a lecturer at a further education college and a television journalist . He entered Parliament in 1983 as the MP for Dunfermline East . He joined the Shadow Cabinet in 1989 as Shadow Secretary of State for Trade , and was later promoted to become Shadow Chancellor of the Exchequer in 1992 . After Labour 's victory in 1997 , he was appointed Chancellor of the Exchequer , becoming the longest-serving holder of that office in modern history .   Brown 's time as Chancellor was marked by major reform of Britain 's monetary and fiscal policy architecture , transferring interest rate setting powers to the Bank of England , by a wide extension of the powers of the Treasury to cover much domestic policy and by transferring responsibility for banking supervision to the Financial Services Authority . Controversial moves included the abolition of advance corporation tax ( ACT ) relief in his first budget , and the removal in his final budget of the 10 % `` starting rate '' of personal income tax which he had introduced in 1999 . In 2007 , Tony Blair resigned as Prime Minister and Labour Leader and Brown was chosen to replace him in an uncontested election .   After initial rises in opinion polls following Brown becoming Prime Minister , Labour 's popularity declined with the onset of a recession in 2008 , leading to poor results in the local and European elections in 2009 . A year later , Labour lost 91 seats in the House of Commons at the 2010 general election , the party 's biggest loss of seats in a single general election since 1931 , making the Conservatives the largest party in a hung parliament . Brown remained in office as Labour negotiated to form a coalition government with the Liberal Democrats . On 10 May 2010 , Brown announced he would stand down as leader of the Labour Party , and instructed the party to put into motion the processes to elect a new leader . Labour 's attempts to retain power failed and on 11 May , he officially resigned as Prime Minister and Leader of the Labour Party . He was succeeded as Prime Minister by David Cameron , and as Leader of the Labour Party by Ed Miliband .   Later , Brown played a prominent role in the campaign surrounding the Scottish independence referendum of 2014 , galvanising support behind maintaining the union .


Granger causality

The Granger causality test is a statistical hypothesis test for determining whether one time series is useful in forecasting another , first proposed in 1969 . Ordinarily , regressions reflect `` mere '' correlations , but Clive Granger argued that causality in economics could be tested for by measuring the ability to predict the future values of a time series using prior values of another time series . Since the question of `` true causality '' is deeply philosophical , and because of the post hoc ergo propter hoc fallacy of assuming that one thing preceding another can be used as a proof of causation , econometricians assert that the Granger test finds only `` predictive causality '' .   A time series X is said to Granger-cause Y if it can be shown , usually through a series of t-tests and F-tests on lagged values of X ( and with lagged values of Y also included ) , that those X values provide statistically significant information about future values of Y.   Granger also stressed that some studies using `` Granger causality '' testing in areas outside economics reached `` ridiculous '' conclusions . `` Of course , many ridiculous papers appeared '' , he said in his Nobel lecture . However , it remains a popular method for causality analysis in time series due to its computational simplicity . The original definition of Granger causality does not account for latent confounding effects and does not capture instantaneous and non-linear causal relationships , though several extensions have been proposed to address these issues .


Gravimeter

A gravimeter is an instrument used in gravimetry for measuring the local gravitational field of the Earth . A gravimeter is a type of accelerometer , specialized for measuring the constant downward acceleration of gravity , which varies by about 0.5 % over the surface of the Earth . Though the essential principle of design is the same as in other accelerometers , gravimeters are typically designed to be much more sensitive in order to measure very tiny fractional changes within the Earth 's gravity of 1 g , caused by nearby geologic structures or the shape of the Earth and by temporal tidal variations . This sensitivity means that gravimeters are susceptible to extraneous vibrations including noise that tend to cause oscillatory accelerations . In practice this is counteracted by integral vibration isolation and signal processing . The constraints on temporal resolution are usually less for gravimeters , so that resolution can be increased by processing the output with a longer time constant . Gravimeters display their measurements in units of gals ( cm/s2 ) , instead of more common units of acceleration .   Gravimeters are used for petroleum and mineral prospecting , seismology , geodesy , geophysical surveys and other geophysical research , and for metrology .   There are two types of gravimeters : relative and absolute . Absolute gravimeters measure the local gravity in absolute units , gals . Relative gravimeters compare the value of gravity at one point with another . They must be calibrated at a location where the gravity is known accurately , and then transported to the location where the gravity is to be measured . They measure the ratio of the gravity at the two points .


Gravity Probe B

Gravity Probe B ( GP-B ) was a satellite-based mission which launched on 20 April 2004 on a Delta II rocket . The spaceflight phase lasted until 2005 ; its aim was to measure spacetime curvature near Earth , and thereby the stress -- energy tensor ( which is related to the distribution and the motion of matter in space ) in and near Earth . This provided a test of general relativity , gravitomagnetism and related models . The principal investigator was Francis Everitt .   Initial results confirmed the expected geodetic effect to an accuracy of about 1 % . The expected frame-dragging effect was similar in magnitude to the current noise level ( the noise being dominated by initially unmodeled effects due to nonuniform coatings on the gyroscopes ) . Work continued to model and account for these sources of error , thus permitting extraction of the frame-dragging signal . By August 2008 , the frame-dragging effect had been confirmed to within 15 % of the expected result , and the December 2008 NASA report indicated that the geodetic effect was confirmed to better than 0.5 % .   In an article published in the journal Physical Review Letters in 2011 , the authors reported analysis of the data from all four gyroscopes results in a geodetic drift rate of and a frame-dragging drift rate of , in good agreement with the general relativity predictions of and , respectively .


Gravity of Mars

The gravity of Mars is a natural phenomenon, due to the law of gravity, or gravitation, by which all things with mass around the planet Mars are brought towards it. It is weaker than Earth's gravity due to the planet's smaller mass. The average gravitational acceleration on Mars is 3.72076 ms−2 (about 38% of that of Earth) and it varies laterally. In general, topography-controlled isostasy drives the short wavelength free-air gravity anomalies. At the same time, convective flow and finite strength of the mantle lead to long-wavelength planetary-scale free-air gravity anomalies over the entire planet. Variation in crustal thickness, magmatic and volcanic activities, impact-induced Moho-uplift, seasonal variation of polar ice caps, atmospheric mass variation and variation of porosity of the crust could also correlate to the lateral variations. Over the years models consisting of an increasing but limited number of spherical harmonics have been produced. Maps produced have included free-air gravity anomaly, Bouguer gravity anomaly, and crustal thickness. In some areas of Mars there is a correlation between gravity anomalies and topography.  Given the known topography, higher resolution gravity field can be inferred. Tidal deformation of Mars by the Sun or Phobos can be measured by its gravity. This reveals how stiff the interior is, and shows that the core is partially liquid. The study of surface gravity of Mars can therefore yield information about different features and provide beneficial information for future landing projects.


Great Barrier Reef

The Great Barrier Reef is the world 's largest coral reef system composed of over 2,900 individual reefs and 900 islands stretching for over 2300 km over an area of approximately 344400 km2 . The reef is located in the Coral Sea , off the coast of Queensland , Australia .   The Great Barrier Reef can be seen from outer space and is the world 's biggest single structure made by living organisms . This reef structure is composed of and built by billions of tiny organisms , known as coral polyps . It supports a wide diversity of life and was selected as a World Heritage Site in 1981 . CNN labelled it one of the seven natural wonders of the world . The Queensland National Trust named it a state icon of Queensland .   A large part of the reef is protected by the Great Barrier Reef Marine Park , which helps to limit the impact of human use , such as fishing and tourism . Other environmental pressures on the reef and its ecosystem include runoff , climate change accompanied by mass coral bleaching , and cyclic population outbreaks of the crown-of-thorns starfish . According to a study published in October 2012 by the Proceedings of the National Academy of Sciences , the reef has lost more than half its coral cover since 1985 .   The Great Barrier Reef has long been known to and used by the Aboriginal Australian and Torres Strait Islander peoples , and is an important part of local groups ' cultures and spirituality . The reef is a very popular destination for tourists , especially in the Whitsunday Islands and Cairns regions . Tourism is an important economic activity for the region , generating over AUD$ 3 billion per year . In November 2014 , Google launched Google Underwater Street View in 3D of the Great Barrier Reef .   A March 2016 report stated that coral bleaching was more widespread than previously thought , seriously affecting the northern parts of the reef as a result of warming ocean temperatures . In October 2016 , Outside published an obituary for the reef ; the article was criticized for being premature and hindering efforts to bolster the resilience of the reef . In March 2017 , the journal Nature published a paper showing that huge sections of a 800-kilometre ( 500 mi ) stretch in the northern part of the reef had died in the course of 2016 due to high water temperatures , an event that the authors put down to the effects of global climate change .


Great Lakes

The Great Lakes ( les Grands-Lacs ) , also called the Laurentian Great Lakes and the Great Lakes of North America , are a series of interconnected freshwater lakes located primarily in the upper mid-east region of North America , on the Canada -- United States border , which connect to the Atlantic Ocean through the Saint Lawrence River . Consisting of Lakes Superior , Michigan , Huron ( or Michigan -- Huron ) , Erie , and Ontario , they form the largest group of freshwater lakes on Earth by total area , and second largest by total volume containing 21 % of the world 's surface fresh water by volume . The total surface is 94250 sqmi , and the total volume ( measured at the low water datum ) is 5439 cumi . Due to their sea-like characteristics ( rolling waves , sustained winds , strong currents , great depths , and distant horizons ) the five Great Lakes have also long been referred to as inland seas . Lake Superior is the second largest lake in the world by area , and Lake Michigan is the largest lake that is entirely within one country . The southern half of the Great Lakes is bordered by the Great Lakes Megalopolis .   The Great Lakes began to form at the end of the last glacial period around 14,000 years ago , as retreating ice sheets exposed the basins they had carved into the land which then filled with meltwater . The lakes have been a major highway for transportation , migration and trade , and they are home to a large number of aquatic species . Many invasive species have been introduced due to trade , and some threaten the region 's biodiversity .


Great Lakes Storm of 1913

The Great Lakes Storm of 1913 , historically referred to as the `` Big Blow , '' the `` Freshwater Fury , '' or the `` White Hurricane , '' was a blizzard with hurricane-force winds that devastated the Great Lakes Basin in the Midwestern United States and the province of Ontario in Canada from November 7 through November 10 , 1913 . The storm was most powerful on November 9 , battering and overturning ships on four of the five Great Lakes , particularly Lake Huron . Deceptive lulls in the storm and the slow pace of weather reports contributed to the storm 's destructiveness .   The deadliest and most destructive natural disaster to hit the lakes in recorded history , the Great Lakes Storm killed more than 250 people , destroyed 19 ships , and stranded 19 others . The financial loss in vessels alone was nearly US $ 5 million ( or about $ in today 's dollars ) . This included about $ 1 million at current value in lost cargo totalling about 68,300 tons , such as coal , iron ore , and grain .   The storm , an extratropical cyclone , originated as the convergence of two major storm fronts , fueled by the lakes ' relatively warm waters -- a seasonal process called a `` November gale '' . It produced 90 mph ( 145 km/h ) wind gusts , waves over 35 feet ( 11 m ) high , and whiteout snowsqualls . Analysis of the storm and its impact on humans , engineering structures , and the landscape led to better forecasting and faster responses to storm warnings , stronger construction ( especially of marine vessels ) , and improved preparedness .


Great Salt Lake

The Great Salt Lake , located in the northern part of the U.S. state of Utah , is the largest salt water lake in the Western Hemisphere , and the eighth-largest terminal lake in the world . In an average year the lake covers an area of around 1700 sqmi , but the lake 's size fluctuates substantially due to its shallowness . For instance , in 1963 it reached its lowest recorded size at 950 square miles ( 2,460 km ² ) , but in 1988 the surface area was at the historic high of 3300 sqmi . In terms of surface area , it is the largest lake in the United States that is not part of the Great Lakes region .   The lake is the largest remnant of Lake Bonneville , a prehistoric pluvial lake that once covered much of western Utah . The three major tributaries to the lake , the Jordan , Weber , and Bear rivers together deposit around 1.1 million tons of minerals in the lake each year . As it is endorheic ( has no outlet besides evaporation ) , it has very high salinity , far saltier than seawater , which makes swimming similar to floating , and its mineral content is steadily increasing . Its shallow , warm waters cause frequent , sometimes heavy lake-effect snows from late fall through spring .   Although it has been called `` America 's Dead Sea '' , the lake provides habitat for millions of native birds , brine shrimp , shorebirds , and waterfowl , including the largest staging population of Wilson 's phalarope in the world .


Green-collar worker

A green-collar worker is a worker who is employed in the environmental sectors of the economy . Environmental green-collar workers ( or green jobs ) satisfy the demand for green development . Generally , they implement environmentally conscious design , policy , and technology to improve conservation and sustainability . Formal environmental regulations as well as informal social expectations are pushing many firms to seek professionals with expertise with environmental , energy efficiency , and clean renewable energy issues . They often seek to make their output more sustainable , and thus more favorable to public opinion , governmental regulation , and the Earth 's ecology .   Green collar workers include professionals such as conservation movement workers , environmental consultants , council environmental services/waste management/recycling managers/officers , environmental or biological systems engineers , green building architects , landscape architects , holistic passive solar building designers , solar energy and wind energy engineers and installers , nuclear engineers , green vehicle engineers , `` green business '' owners , green vehicle , organic farmers , environmental lawyers , ecology educators , and ecotechnology workers , and sales staff working with these services or products . Green collar workers also include vocational or trade-level workers : electricians who install solar panels , plumbers who install solar water heaters , recycling centre/MRF attendants , process managers and collectors , construction workers who build energy-efficient green buildings and wind power farms , construction workers who weatherize buildings to make them more energy efficient , or other workers involved in clean , renewable , sustainable future energy development .   There is a growing movement to incorporate social responsibility within the green industries . A sustainable green economy simultaneously values the importance of natural resources and inclusive , equitable , and healthy opportunities for all communities .   In the context of the current world economic crisis , many experts now argue that a massive push to develop renewable sources of energy could create millions of new jobs and help the economy recover while simultaneously improving the environment , increasing labour conditions in poor economies , and strengthening energy and food security .


Green Climate Fund

The Green Climate Fund ( GCF ) is a fund within the framework of the UNFCCC founded as a mechanism to assist developing countries in adaptation and mitigation practices to counter climate change . The GCF is based in the new Songdo district of Incheon , South Korea . It is governed by a Board of 24 members and initially supported by a Secretariat .   `` The Green Climate Fund will support projects , programmes , policies and other activities in developing country Parties using thematic funding windows '' . It is intended to be the centrepiece of efforts to raise Climate Finance of $ 100 billion a year by 2020 . This is not an official figure for the size of the Fund itself , however . Disputes also remain as to whether the funding target will be based on public sources , or whether `` leveraged '' private finance will be counted towards the total . A total of US$ 10.3 billion has been pledged so far , which is meant to cover investments over a four year period . Only a fraction of this sum had been pledged as of July 2013 , mostly to cover start-up costs .   According to the Climate & Development Knowledge Network , at the third meeting of the Board in Berlin in March 2013 , members agreed on how to move forward with the fund 's Business Model Framework ( BMF ) . They identified the need to assess various options for how nations could access the fund , approaches for involving the private sector , plus ways to measure results and ensure requests for monies are country-driven . At the fourth Board meeting in Songdo , South Korea , in June 2013 , Hela Cheikhrouhou , a Tunisian national , was selected to become the Fund 's first Executive Director . Cheikhrouhou left the Fund in September 201


Greenhouse

A greenhouse ( also called a glasshouse , or , if with sufficient heating , a hothouse ) is a structure with walls and roof made chiefly of transparent material , such as glass , in which plants requiring regulated climatic conditions are grown . These structures range in size from small sheds to industrial-sized buildings . A miniature greenhouse is known as a cold frame . The interior of a greenhouse exposed to sunlight becomes significantly warmer than the external ambient temperature , protecting its contents in cold weather .   Many commercial glass greenhouses or hothouses are high tech production facilities for vegetables or flowers . The glass greenhouses are filled with equipment including screening installations , heating , cooling , lighting , and may be controlled by a computer to optimize conditions for plant growth . Different techniques are then used to evaluate optimality-degrees and comfort ratio of greenhouse micro-climate ( i.e. , air temperature , relative humidity and vapor pressure deficit ) in order to reduce production risk prior to cultivation of a specific crop .


Greenhouse effect

The greenhouse effect is the process by which radiation from a planet 's atmosphere warms the planet 's surface to a temperature above what it would be without its atmosphere .   If a planet 's atmosphere contains radiatively active gases ( i.e. , greenhouse gases ) the atmosphere will radiate energy in all directions . Part of this radiation is directed towards the surface , warming it . The downward component of this radiation -- that is , the strength of the greenhouse effect -- will depend on the atmosphere 's temperature and on the amount of greenhouse gases that the atmosphere contains .   On Earth , the atmosphere is warmed by absorption of infrared thermal radiation from the underlying surface ( heated by the sun ) , absorption of shorter wavelength radiant energy from the sun , and convective heat fluxes from the surface . Greenhouse gases in the atmosphere radiate energy , some of which is directed to the surface and lower atmosphere . The mechanism that produces this difference between the actual surface temperature and the effective temperature is due to the atmosphere and is known as the greenhouse effect .   Earth 's natural greenhouse effect is critical to supporting life . Human activities , primarily the burning of fossil fuels and clearing of forests , have intensified the natural greenhouse effect , causing global warming .   The mechanism is named after a faulty analogy with the effect of solar radiation passing through glass and warming a greenhouse . The way a greenhouse retains heat is fundamentally different , as a greenhouse works by reducing airflow and retaining warm air inside the structure .


Greenhouse gas

A greenhouse gas ( abbrev . GHG ) is a gas in an atmosphere that absorbs and emits radiation within the thermal infrared range . This process is the fundamental cause of the greenhouse effect . The primary greenhouse gases in Earth 's atmosphere are water vapor , carbon dioxide , methane , nitrous oxide , and ozone . Without greenhouse gases , the average temperature of Earth 's surface would be about -18 ° C , rather than the present average of 15 ° C . In the Solar System , the atmospheres of Venus , Mars and Titan also contain gases that cause a greenhouse effect .   Human activities since the beginning of the Industrial Revolution ( taken as the year 1750 ) have produced a 40 % increase in the atmospheric concentration of carbon dioxide , from 280 ppm in 1750 to 406 ppm in early 2017 . This increase has occurred despite the uptake of a large portion of the emissions by various natural `` sinks '' involved in the carbon cycle . Anthropogenic carbon dioxide emissions ( i.e. , emissions produced by human activities ) come from combustion of fossil fuels , principally coal , oil , and natural gas , along with deforestation , soil erosion and animal agriculture .   It has been estimated that if greenhouse gas emissions continue at the present rate , Earth 's surface temperature could exceed historical values as early as 2047 , with potentially harmful effects on ecosystems , biodiversity and the livelihoods of people worldwide . Recent estimates suggest that on the current emissions trajectory the Earth could pass a threshold of 2 ° C global warming , which the United Nations ' IPCC designated as the upper limit to avoid `` dangerous '' global warming , by 2036 .


Greenhouse gas emissions by the United States

According to the U.S. Environmental Protection Agency ( EPA ) , the United States produced 6,587 million metric tonnes of carbon-dioxide equivalent greenhouse gas ( GHG ) emissions in 2015 . Compared to 2014 levels , U.S. greenhouse gas emissions decreased in 2015 . Compared to levels in 1990 , emissions have increased by about 4 percent . From year to year , emissions can rise and fall due to changes in the economy , the price of fuel , and other factors . The EPA has attributed recent decreases to a reduction in emissions from fossil fuel combustion , which was a result of multiple factors including substitution from coal to natural gas consumption in the electric power sector ; warmer winter conditions that reduced demand for heating fuel in the residential and commercial sectors ; and a slight decrease in electricity demand .   While the Bush administration opted against Kyoto-type policies to reduce emissions , the Obama administration and various state , local , and regional governments have attempted to adopt some Kyoto Protocol goals on a local basis . For example , the Regional Greenhouse Gas Initiative ( RGGI ) founded in January 2007 is a state-level emissions capping and trading program by nine northeastern U.S. states . In December 2009 President Obama set a target for reducing U.S. greenhouse gas ( GHG ) emissions in the range of 17 % below 2005 levels by 2020 .   The U.S. State Department offered a nation-level perspective in the Fourth US Climate Action Report ( USCAR ) to the United Nations Framework Convention on Climate Change , including measures to address climate change . The report showed that the country was on track to achieve President Bush 's goal of reducing greenhouse gas emissions per unit of gross domestic product ) by 18 percent from 2002 to 2012 . Over that same period , actual GHG emissions were projected to increase by 11 percent . The report estimated that in 2006 , U.S. GHG emissions decreased 1.5 percent from 2005 to 7,075.6 million tonnes of carbon dioxide equivalent . This was an increase of 15.1 percent from the 1990 levels of 6,146.7 million tonnes ( or 0.9 percent annual increase ) , and an increase of 1.4 percent from the 2000 levels of 6,978.4 million tonnes . By 2012 GHG emissions were projected to increase to more than 7,709 million tonnes of carbon dioxide equivalent , which would be 26 percent above 1990 levels .


Greenland

Greenland ( -LSB- ˈɡriːnlənd -RSB- Kalaallit Nunaat -LSB- kaˈlaːɬit ˈnunaːt -RSB- Grønland -LSB- ˈɡ̊ʁɶnˌlanˀ -RSB- ) is an autonomous constituent country within the Kingdom of Denmark between the Arctic and Atlantic Oceans , east of the Canadian Arctic Archipelago . Though physiographically a part of the continent of North America , Greenland has been politically and culturally associated with Europe ( specifically Norway and Denmark , the colonial powers , as well as the nearby island of Iceland ) for more than a millennium . The majority of its residents are Inuit , whose ancestors began migrating from the Canadian mainland in the 13th century , gradually settling across the island .   Greenland is the world 's largest island ( Australia , although larger , is generally considered to be a continental landmass rather than an island ) . Three-quarters of Greenland is covered by the only permanent ice sheet outside Antarctica . With a population of about 56,480 ( 2013 ) , it is the least densely populated country in the world . The Arctic Umiaq Line ferry acts as a lifeline for western Greenland , connecting the various cities and settlements .   Greenland has been inhabited off and on for at least the last 4,500 years by Arctic peoples whose forebears migrated there from what is now Canada . Norsemen settled the uninhabited southern part of Greenland beginning in the 10th century , and Inuit peoples arrived in the 13th century . The Norse colonies disappeared in the late 15th century . Soon after their demise , beginning in 1499 , the Portuguese briefly explored and claimed the island , naming it Terra do Lavrador ( later applied to Labrador in Canada ) . In the early 18th century , Scandinavian explorers reached Greenland again . To strengthen trading and power , Denmark-Norway affirmed sovereignty over the island .   Denmark -- Norway claimed Greenland for centuries . Greenland was settled by Vikings ( of Norwegian origin ) more than a thousand years ago , who had previously settled Iceland to escape persecution from the King of Norway and his central government . Vikings set sail from Greenland and Iceland , encountering North America nearly 500 years before Columbus reached the Caribbean islands . They attempted to colonize land . Though under continuous influence of Norway and Norwegians , Greenland was not formally under the Norwegian crown until 1262 . The Kingdom of Norway was extensive and a military power until the mid-14th century . Norway was dramatically hit with a larger death toll than Denmark by the Black Death , forcing Norway to accept a union in which the central government , university and other fundamental institutions were located in Copenhagen . Thus , the two kingdoms ' resources were directed at creating Copenhagen . Norway became the weaker part and lost sovereignty over Greenland in 1814 when the union was dissolved . Greenland became a Danish colony in 1814 , and was made a part of the Danish Realm in 1953 under the Constitution of Denmark .   In 1973 , Greenland joined the European Economic Community with Denmark . However , in a referendum in 1982 , a majority of the population voted for Greenland to withdraw from the EEC which was effected in 1985 . Greenland contains the world 's largest and most northernly national park , Northeast Greenland National Park ( Kalaallit Nunaanni nuna eqqissisimatitaq ) . Established in 1974 and expanded to its present size in 1988 , it protects 972001 km2 of the interior and northeastern coast of Greenland and is bigger than all but twenty-nine countries in the world . Greenland is divided into four municipalities - Sermersooq , Kujalleq , Qaasuitsup , and Qeqqata .   In 1979 , Denmark had granted home rule to Greenland , and in 2008 , Greenlanders voted in favour of the Self-Government Act , which transferred more power from the Danish royal government to the local Greenlandic government . Under the new structure , in effect since 21 June 2009 , Greenland can gradually assume responsibility for policing , judicial system , company law , accounting , and auditing ; mineral resource activities ; aviation ; law of legal capacity , family law and succession law ; aliens and border controls ; the working environment ; and financial regulation and supervision , while the Danish government retains control of foreign affairs and defence . It also retains control of monetary policy , providing an initial annual subsidy of DKK 3.4 billion , which is planned to diminish gradually over time . Greenland expects to grow its economy based on increased income from the extraction of natural resources . The capital , Nuuk , held the 2016 Arctic Winter Games . At 70 % , Greenland has one of the highest shares of renewable energy in the world , mostly coming from hydropower .


Greenland ice sheet

The Greenland ice sheet ( Grønlands indlandsis , Sermersuaq ) is a vast body of ice covering 1710000 km ² , roughly 80 % of the surface of Greenland .   It is the second largest ice body in the world , after the Antarctic ice sheet . The ice sheet is almost 2400 km long in a north-south direction , and its greatest width is 1100 km at a latitude of 77 ° N , near its northern margin . The mean altitude of the ice is 2135 m . The thickness is generally more than 2 km and over 3 km at its thickest point . It is not the only ice mass of Greenland -- isolated glaciers and small ice caps cover between 76000 and around the periphery . If the entire 2850000 km3 of ice were to melt , it would lead to a global sea level rise of 7.2 m . The Greenland Ice Sheet is sometimes referred to under the term inland ice , or its Danish equivalent , indlandsis . It is also sometimes referred to as an ice cap .


Greenpeace

Greenpeace is a non-governmental environmental organization with offices in over 40 countries and with an international coordinating body in Amsterdam , the Netherlands . Founded by Canadian and US ex-pat environmental activists in 1971 , Greenpeace states its goal is to `` ensure the ability of the Earth to nurture life in all its diversity '' and focuses its campaigning on worldwide issues such as climate change , deforestation , overfishing , commercial whaling , genetic engineering , and anti-nuclear issues . It uses direct action , lobbying , research , and ecotage to achieve its goals . The global organization does not accept funding from governments , corporations , or political parties , relying on 2.9 million individual supporters and foundation grants . Greenpeace has a general consultative status with the United Nations Economic and Social Council and is a founding member of the INGO Accountability Charter ; an international non-governmental organization that intends to foster accountability and transparency of non-governmental organizations .   Greenpeace is known for its direct actions and has been described as the most visible environmental organization in the world . Greenpeace has raised environmental issues to public knowledge , and influenced both the private and the public sector . Greenpeace has also been a source of controversy ; its motives and methods ( some of the latter being illegal ) have received criticism , including an open letter from more than 100 Nobel laureates urging Greenpeace to end its campaign against genetically modified organisms ( GMOs ) . The organization 's direct actions have sparked legal actions against Greenpeace activists , such as fines and suspended sentences for destroying a test plot of genetically modified wheat and damaging the Nazca Lines , a UN World Heritage site in Peru .


Grissom Air Reserve Base

Grissom Air Reserve Base is a United States Air Force base , located about 12 mi north of Kokomo in Cass County , Indiana and Miami County , Indiana . The facility was established as Naval Air Station Bunker Hill in 1942 and an active Air Force installation from 1954 to 1994 . Since then it is a joint-use civil airport/military base with the Grissom Aeroplex providing general aviation and charter service .   The base is named in memory of astronaut and Indiana native Virgil I. `` Gus '' Grissom , who , along with fellow astronauts Ed White and Roger Chaffee , perished in the Apollo 1 fire at Cape Canaveral Air Force Station Launch Complex 34 in 1967 .


Grizzly bear

The grizzly bear ( Ursus arctos ssp . ) , less commonly known as the silvertip bear , is a large subspecies of brown bear inhabiting North America . Scientists generally do not use the name grizzly bear but call it the North American brown bear .   Multiple morphological forms sometimes recognized as subspecies exist , including the mainland grizzly ( Ursus arctos horribilis ) , Kodiak bear ( U. a. middendorffi ) , peninsular grizzly ( U. a. gyas ) , and the recently extinct California grizzly ( U. a. californicus † ) and Mexican grizzly bear ( U. a. nelsoni † ) . On average bears near the coast tend to be larger while inland Grizzlies tend to be smaller .   The Ussuri brown bear ( U. a. lasiotus ) inhabiting Russia , Northern China , and Korea is sometimes referred to as black grizzly although it is a different subspecies from the bears in America .


Gulf Coast of the United States

The Gulf Coast of the United States is the coastline along which the Southern United States meets the Gulf of Mexico . The coastal states that have a shoreline on the Gulf of Mexico are Texas , Louisiana , Mississippi , Alabama , and Florida , and these are known as the Gulf States .   The economy of the Gulf Coast area is dominated by industries related to energy , petrochemicals , fishing , aerospace , agriculture , and tourism . The large cities of the region are ( from west to east ) Brownsville , Corpus Christi , Houston , Galveston , Beaumont , Lafayette , Baton Rouge , New Orleans , Biloxi , Mobile , Pensacola , St. Petersburg , Tampa , and increasingly , Sarasota ; all are the centers of their respective metropolitan areas and contain large ports . ( Baton Rouge is relatively far from the Gulf of Mexico ; its port is on the Mississippi River , as is the port of New Orleans . )


Gulf Stream

The Gulf Stream , together with its northern extension the North Atlantic Drift , is a warm and swift Atlantic ocean current that originates in the Gulf of Mexico and stretches to the tip of Florida , and follows the eastern coastlines of the United States and Newfoundland before crossing the Atlantic Ocean . The process of western intensification causes the Gulf Stream to be a northward accelerating current off the east coast of North America . At about , it splits in two , with the northern stream , the North Atlantic Drift , crossing to Northern Europe and the southern stream , the Canary Current , recirculating off West Africa .   The Gulf Stream influences the climate of the east coast of North America from Florida to Newfoundland , and the west coast of Europe . Although there has been recent debate , there is consensus that the climate of Western Europe and Northern Europe is warmer than it would otherwise be due to the North Atlantic drift which is the northeastern section of the Gulf Stream . It is part of the North Atlantic Gyre . Its presence has led to the development of strong cyclones of all types , both within the atmosphere and within the ocean . The Gulf Stream is also a significant potential source of renewable power generation . The Gulf Stream may be slowing down as a result of climate change .   The Gulf Stream is typically 100 kilometres ( 62 mi ) wide and 800 metres ( 2,600 ft ) to 1,200 metres ( 3,900 ft ) deep . The current velocity is fastest near the surface , with the maximum speed typically about 2.5 metres per second ( 5.6 mph ) .


Gulf War

The Gulf War ( 2 August 1990 -- 28 February 1991 ) , codenamed Operation Desert Shield ( 2 August 1990 -- 17 January 1991 ) for operations leading to the buildup of troops and defense of Saudi Arabia and Operation Desert Storm ( 17 January 1991 -- 28 February 1991 ) in its combat phase , was a war waged by coalition forces from 35 nations led by the United States against Iraq in response to Iraq 's invasion and annexation of Kuwait .   The war is also known under other names , such as the Persian Gulf War , First Gulf War , Gulf War I , Kuwait War , First Iraq War , or Iraq War before the term `` Iraq War '' became identified instead with the 2003 Iraq War ( also referred to in the US as `` Operation Iraqi Freedom '' ) .  The Iraqi Army 's occupation of Kuwait that began 2 August 1990 was met with international condemnation , and brought immediate economic sanctions against Iraq by members of the UN Security Council . US President George H. W. Bush deployed US forces into Saudi Arabia , and urged other countries to send their own forces to the scene . An array of nations joined the coalition , the largest military alliance since World War II . The great majority of the coalition 's military forces were from the US , with Saudi Arabia , the United Kingdom , and Egypt as leading contributors , in that order . Kuwait and Saudi Arabia paid around US$ 32 billion of the US$ 60 billion cost .   The war was marked by the introduction of live news broadcasts from the front lines of the battle , principally by the US network CNN . The war has also earned the nickname Video Game War after the daily broadcast of images from cameras on board US bombers during Operation Desert Storm .   The initial conflict to expel Iraqi troops from Kuwait began with an aerial and naval bombardment on 17 January 1991 , continuing for five weeks . This was followed by a ground assault on 24 February . This was a decisive victory for the coalition forces , who liberated Kuwait and advanced into Iraqi territory . The coalition ceased its advance , and declared a ceasefire 100 hours after the ground campaign started . Aerial and ground combat was confined to Iraq , Kuwait , and areas on Saudi Arabia 's border . Iraq launched Scud missiles against coalition military targets in Saudi Arabia and against Israel .


Habitat destruction

Habitat destruction is the process in which natural habitat is rendered unable to support the species present . In this process , the organisms that previously used the site are displaced or destroyed , reducing biodiversity . Habitat destruction by human activity is mainly for the purpose of harvesting natural resources for industry production and urbanization . Clearing habitats for agriculture is the principal cause of habitat destruction . Other important causes of habitat destruction include mining , logging , trawling and urban sprawl . Habitat destruction is currently ranked as the primary cause of species extinction worldwide . It is a process of natural environmental change that may be caused by habitat fragmentation , geological processes , climate change or by human activities such as the introduction of invasive species , ecosystem nutrient depletion , and other human activities   The terms habitat loss and habitat reduction are also used in a wider sense , including loss of habitat from other factors , such as water and noise pollution .


Hawthorne effect

The Hawthorne effect ( also referred to as the observer effect ) is a type of reactivity in which individuals modify an aspect of their behavior in response to their awareness of being observed . The original research at the Hawthorne Works in Cicero , Illinois , on lighting changes and work structure changes such as working hours and break times was originally interpreted by Elton Mayo and others to mean that paying attention to overall worker needs would improve productivity . Later interpretations such as that done by Landsberger suggested that the novelty of being research subjects and the increased attention from such could lead to temporary increases in workers ' productivity . This interpretation was dubbed `` the Hawthorne effect '' .


Hazard

A hazard is a situation that poses a level of threat to life , health , property , or environment . Hazards can be dormant or potential , with only a theoretical risk of harm ; however , once a hazard becomes `` active '' , it can create an emergency . A hazardous situation that has come to pass is called an incident . Hazard , consequence and probability interact together to create risk .   Identification of hazard risks is the first step in performing a risk assessment .


Headlamp

A headlamp is a lamp attached to the front of a vehicle to light the road ahead . While it is common for the term headlight to be used interchangeably in informal discussion , headlamp is the term for the device itself , while headlight properly refers to the beam of light produced and distributed by the device .   Headlamp performance has steadily improved throughout the automobile age , spurred by the great disparity between daytime and nighttime traffic fatalities : the US National Highway Traffic Safety Administration states that nearly half of all traffic-related fatalities occur in the dark , despite only 25 % of traffic travelling during darkness .   Other vehicles , such as trains and aircraft , are required to have headlamps . Bicycle headlamps are often used on bicycles , and are required in some jurisdictions . They can be powered by a battery or a small generator mechanically integrated into the workings of the bicycles .


Heat flux sensor

A heat flux sensor is a transducer that generates an electrical signal proportional to the total heat rate applied to the surface of the sensor . The measured heat rate is divided by the surface area of the sensor to determine the heat flux .   The heat flux can have different origins ; in principle convective , radiative as well as conductive heat can be measured . Heat flux sensors are known under different names , such as heat flux transducers , heat flux gauges , heat flux plates . Some instruments that actually are single-purpose heat flux sensors like pyranometers for solar radiation measurement . Other heat flux sensors include Gardon gauges ( also known as a circular-foil gauge ) , thin-film thermopiles , and Schmidt-Boelter gauges . In SI units , the heat rate is measured in Watts , and the heat flux is computed in Watts per meter squared .


Heat stroke

Heat stroke , also known as sun stroke , is a severe heat illness , defined as hyperthermia with a body temperature greater than 40.6 C because of environmental heat exposure with lack of thermoregulation . This is distinct from a fever , where there is a physiological increase in the temperature set point of the body . The term `` stroke '' in `` heat stroke '' is a misnomer in that it does not involve a blockage or hemorrhage of blood flow to the brain . Preventive measures include drinking plenty of cool liquids and avoiding excessive heat and humidity , especially in unventilated spaces , such as parked cars , that can overheat quickly . Treatment requires rapid physical cooling of the body .


Heat transfer

Heat transfer is a discipline of thermal engineering that concerns the generation , use , conversion , and exchange of thermal energy and heat between physical systems . Heat transfer is classified into various mechanisms , such as thermal conduction , thermal convection , thermal radiation , and transfer of energy by phase changes . Engineers also consider the transfer of mass of differing chemical species , either cold or hot , to achieve heat transfer . While these mechanisms have distinct characteristics , they often occur simultaneously in the same system .   Heat conduction , also called diffusion , is the direct microscopic exchange of kinetic energy of particles through the boundary between two systems . When an object is at a different temperature from another body or its surroundings , heat flows so that the body and the surroundings reach the same temperature , at which point they are in thermal equilibrium . Such spontaneous heat transfer always occurs from a region of high temperature to another region of lower temperature , as described by the second law of thermodynamics .   Heat convection occurs when bulk flow of a fluid ( gas or liquid ) carries heat along with the flow of matter in the fluid . The flow of fluid may be forced by external processes , or sometimes ( in gravitational fields ) by buoyancy forces caused when thermal energy expands the fluid ( for example in a fire plume ) , thus influencing its own transfer . The latter process is often called `` natural convection '' . All convective processes also move heat partly by diffusion , as well . Another form of convection is forced convection . In this case the fluid is forced to flow by use of a pump , fan or other mechanical means .   Thermal radiation occurs through a vacuum or any transparent medium ( solid or fluid ) . It is the transfer of energy by means of photons in electromagnetic waves governed by the same laws .


Heat wave

A heat wave is a prolonged period of excessively hot weather , which may be accompanied by high humidity , especially in oceanic climate countries . While definitions vary , a heat wave is measured relative to the usual weather in the area and relative to normal temperatures for the season . Temperatures that people from a hotter climate consider normal can be termed a heat wave in a cooler area if they are outside the normal climate pattern for that area .   The term is applied both to hot weather variations and to extraordinary spells of hot which may occur only once a century . Severe heat waves have caused catastrophic crop failures , thousands of deaths from hyperthermia , and widespread power outages due to increased use of air conditioning . A heat wave is considered extreme weather , and a danger because heat and sunlight may overheat the human body .


Hekla

Hekla ( -LSB- 3 = Is-Hekla_pronunciation . ogg -RSB- ) , or Hecla , is a stratovolcano in the south of Iceland with a height of 1491 m. Hekla is one of Iceland 's most active volcanoes ; over 20 eruptions have occurred in and around the volcano since 874 . During the Middle Ages , Europeans called the volcano the `` Gateway to Hell '' .   Hekla is part of a volcanic ridge , 40 km long . The most active part of this ridge , a fissure about 5.5 km long named Heklugjá , is considered to be the volcano Hekla proper . Hekla looks rather like an overturned boat , with its keel being a series of craters , two of which are generally the most active .   The volcano 's frequent large eruptions have covered much of Iceland with tephra and these layers can be used to date eruptions of Iceland 's other volcanos . 10 % of the tephra created in Iceland in the last thousand years has come from Hekla , amounting to 5 km3 . The volcano has produced one of the largest volumes of lava of any in the world in the last millennium , around 8 km3 .


Henrik Svensmark

Henrik Svensmark ( born 1958 ) is a physicist and professor in the Division of Solar System Physics at the Danish National Space Institute ( DTU Space ) in Copenhagen . He is known for his theory on the effects of cosmic rays on cloud formation as an indirect cause of global warming . He detailed his work in the book The Chilling Stars as well as the film The Cloud Mystery .


Henry's law

In chemistry , Henry 's law is one of the gas laws formulated by the English chemist William Henry , who studied the topic in the early 19th century . In his publication about the quantity of gases absorbed by water , he described the results of his experiments :   ... `` water takes up , of gas condensed by one , two , or more additional atmospheres , a quantity which , ordinarily compressed , would be equal to twice , thrice , & c. the volume absorbed under the common pressure of the atmosphere . ''   In other words , the amount of dissolved gas is proportional to its partial pressure in the gas phase . The proportionality factor is called the Henry 's law constant .   An example where Henry 's law is at play is in the depth-dependent dissolution of oxygen and nitrogen in the blood of underwater divers that changes during decompression , leading to decompression sickness . An everyday example is given by one 's experience with carbonated soft drinks , which contain dissolved carbon dioxide . Before opening , the gas above the drink in its container is almost pure carbon dioxide , at a pressure higher than atmospheric pressure . After the bottle is opened , this gas escapes , moving the partial pressure of carbon dioxide above the liquid to be much lower , resulting in degassing as the dissolved carbon dioxide comes out of solution .


Highway

A highway is any public road or other public way on land . It is used for major roads , but also includes other public roads and public tracks : It is not an equivalent term to controlled-access highway , or a translation for autobahn , autoroute , etc. .   In North American and Australian English , major roads such as controlled-access highways or arterial roads are often state highways ( Canada : provincial highways ) . Other roads may be designated `` county highways '' in the US and Ontario . These classifications refer to the level of government ( state , provincial , county ) that maintains the roadway .   In British English , `` highway '' is primarily a legal term . Everyday use normally implies roads , while the legal use covers any route or path with a public right of access , including footpaths etc. .   The term has led to several related derived terms , including highway system , highway code , highway patrol and highwayman .   The term highway exists in distinction to `` waterway '' .


Hilda Heine

Hilda Cathy Heine ( born April 6 , 1951 ) is a Marshallese educator and politician , currently serving as the eighth President of the Marshall Islands . Prior to assuming office , she served as the Minister of Education . She was the first individual in the Marshall Islands to earn a doctorate degree , and the founder of the women 's rights group Women United Together Marshall Islands ( WUTMI ) .   Heine is the first woman to hold the presidency of the Marshall Islands . She is also the first female president of any Micronesian country , and only the fourth woman to serve as head of government for any independent Pacific nation ( following Jenny Shipley and Helen Clark of New Zealand and Julia Gillard of Australia ) . She is one of only three women currently serving in the Nitijeļā , the country 's legislature , as of January 2016 .


Hillary Clinton

Hillary Diane Rodham Clinton ( -LSB- ˈhɪləri_daɪˈæn_ˈrɒdəm_ˈklɪntən -RSB- born October 26 , 1947 ) is an American politician who was the 67th United States Secretary of State from 2009 to 2013 , U.S. Senator from New York from 2001 to 2009 , First Lady of the United States from 1993 to 2001 , and the Democratic Party 's nominee for President of the United States in the 2016 election .   Born in Chicago , Illinois , and raised in the Chicago suburb of Park Ridge , Clinton graduated from Wellesley College in 1969 , and earned a J.D. from Yale Law School in 1973 . After serving as a congressional legal counsel , she moved to Arkansas and married Bill Clinton in 1975 . In 1977 , she co-founded Arkansas Advocates for Children and Families . She was appointed the first female chair of the Legal Services Corporation in 1978 and became the first female partner at Rose Law Firm the following year . As First Lady of Arkansas , she led a task force whose recommendations helped reform Arkansas 's public schools .   As First Lady of the United States , Clinton was an advocate for gender equality and healthcare reform . Her relationship with her husband came under public speculation during the Lewinsky scandal , forcing her to issue a statement reaffirming her commitment to the marriage . Clinton was elected in 2000 as the first female senator from New York . She was re-elected to the Senate in 2006 . Running for president in 2008 , she won far more delegates than any previous female candidate , but lost the Democratic nomination to Barack Obama .   As Secretary of State in the Obama administration from 2009 to 2013 , Clinton responded to the Arab Spring , during which she advocated the U.S. military intervention in Libya . She helped organize a diplomatic isolation and international sanctions regime against Iran , in an effort to force curtailment of that country 's nuclear program ; this would eventually lead to the multinational Joint Comprehensive Plan of Action agreement in 2015 . Leaving office after Obama 's first term , she wrote her fifth book and undertook speaking engagements .   Clinton made a second presidential run in 2016 . She received the most votes and primary delegates in the 2016 Democratic primaries , and formally accepted her party 's nomination for President of the United States on July 28 , 2016 with vice presidential running mate Senator Tim Kaine . She became the first female candidate to be nominated for president by a major U.S. political party . Despite winning a plurality of the national popular vote , Clinton lost the Electoral College and the presidency to her Republican opponent Donald Trump . Following her loss , in 2017 she decided to focus on being a self-described `` activist citizen '' .


Himalayas

The Himalayas , or Himalaya , ( -LSB- ˌhɪməˈleɪ.ə -RSB- or -LSB- hɪˈmɑːləjə -RSB- ) form a mountain range in Asia separating the plains of the Indian subcontinent from the Tibetan Plateau .   The Himalayan range has many of the Earth 's highest peaks , including the highest , Mount Everest . The Himalayas include over fifty mountains exceeding 7200 m in elevation , including ten of the fourteen 8000m peaks . By contrast , the highest peak outside Asia -- Aconcagua , in the Andes -- is 6961 m tall .   The Himalayan range is bordered on the northwest by the Karakoram and Hindu Kush ranges , on the north by the Tibetan Plateau , and on the south by the Indo-Gangetic Plain . The Himalayas are distinct from the other great ranges of central Asia , although sometimes the term Himalaya is loosely used to include the Karakoram and some of the other ranges . The Himalayas are spread across five countries : Nepal , India , Bhutan , China and Pakistan , with the first three countries having sovereignty over most of the range . Some of the world 's major rivers , the Indus , the Ganges , and the Tsangpo-Brahmaputra , rise in the Himalayas , and their combined drainage basin is home to roughly 600 million people . The Himalayas have profoundly shaped the cultures of South Asia ; many Himalayan peaks are sacred in Hinduism and Buddhism .   Lifted by the subduction of the Indian tectonic plate under the Eurasian Plate , the Himalayan Mountain range runs , west-northwest to east-southeast , in an arc 2400 km long . Its western anchor , Nanga Parbat , lies just south of the northernmost bend of Indus river . Its eastern anchor , Namcha Barwa , is just west of the great bend of the Tsangpo river . The range varies in width from 400 km in the west to 150 km in the east .


Hip hop music

Hip hop music , also called hip-hop or rap music , is a music genre developed in the United States by inner-city African Americans in the 1970s which consists of a stylized rhythmic music that commonly accompanies rapping , a rhythmic and rhyming speech that is chanted . It developed as part of hip hop culture , a subculture defined by four key stylistic elements : MCing/rapping , DJing/scratching with turntables , break dancing , and graffiti writing . Other elements include sampling beats or bass lines from records ( or synthesized beats and sounds ) , and rhythmic beatboxing . While often used to refer solely to rapping , `` hip hop '' more properly denotes the practice of the entire subculture . The term hip hop music is sometimes used synonymously with the term rap music , though rapping is not a required component of hip hop music ; the genre may also incorporate other elements of hip hop culture , including DJing , turntablism , scratching , beatboxing , and instrumental tracks .   Hip hop as both a musical genre and a culture was formed during the 1970s when block parties became increasingly popular in New York City , particularly among African-American youth residing in the Bronx . At block parties DJs played percussive breaks of popular songs using two turntables and a DJ mixer to be able to play breaks from two copies of the same record , alternating from one to the other and extending the `` break '' . Hip hop 's early evolution occurred as sampling technology and drum machines became widely available and affordable . Turntablist techniques such as scratching and beatmatching developed along with the breaks and Jamaican toasting , a chanting vocal style , was used over the beats . Rapping developed as a vocal style in which the artist speaks or chants along rhythmically with an instrumental or synthesized beat . Notable artists at this time include DJ Kool Herc , Grandmaster Flash and The Furious Five , Fab Five Freddy , Marley Marl , Afrika Bambaataa , Kool Moe Dee , Kurtis Blow , Doug E. Fresh , Whodini , Warp 9 , The Fat Boys , and Spoonie Gee . The Sugarhill Gang 's 1979 song `` Rapper 's Delight '' is widely regarded to be the first hip hop record to gain widespread popularity in the mainstream . The 1980s marked the diversification of hip hop as the genre developed more complex styles . Prior to the 1980s , hip hop music was largely confined within the United States . However , during the 1980s , it began to spread to music scenes in dozens of countries , many of which mixed hip hop with local styles to create new subgenres .   New school hip hop was the second wave of hip hop music , originating in 1983 -- 84 with the early records of Run-D.M.C . and LL Cool J . The Golden age hip hop period was an innovative period between the mid-1980s and the early 1990s . Notable artists from this era include the Juice Crew , Public Enemy , Eric B. & Rakim , Boogie Down Productions and KRS-One , EPMD , Slick Rick , Beastie Boys , Kool G Rap , Big Daddy Kane , Ultramagnetic MCs , De La Soul , and A Tribe Called Quest . Gangsta rap is a subgenre of hip hop that often focuses on the violent lifestyles and impoverished conditions of inner-city African-American youth . Schoolly D , N.W.A , Ice-T , Ice Cube , and the Geto Boys are key founding artists , known for mixing the political and social commentary of political rap with the criminal elements and crime stories found in gangsta rap . In the West Coast hip hop style , G-funk dominated mainstream hip hop for several years during the 1990s . East Coast hip hop in the early to mid 1990s was dominated by the Afrocentric jazz rap and alternative hip hop of the Native Tongues posse as well as the hardcore rap of artists such as Nas , Wu-Tang Clan , and Notorious B.I.G. .   In the 1990s , hip hop began to diversify with other regional styles emerging , such as Southern rap and Atlanta hip hop . At the same time , hip hop continued to be assimilated into other genres of popular music , examples being Neo soul and nu metal . Hip hop became a best-selling pop music genre in the mid-1990s and the top selling music genre by 1999 . The popularity of hip hop music continued through the 2000s , with hip hop influences also increasingly finding their way into mainstream pop . The United States also saw the success of regional styles such as crunk , a Southern genre that emphasized the beats and music more than the lyrics . Starting in 2005 , sales of hip hop music in the United States began to severely wane . During the mid-2000s , alternative hip hop secured a place in the mainstream , due in part to the crossover success of artists such as OutKast and Kanye West .


History of economic thought

The history of economic thought deals with different thinkers and theories in the subject that became political economy and economics , from the ancient world to the present day . It encompasses many disparate schools of economic thought . Ancient Greek writers such as the philosopher Aristotle examined ideas about the art of wealth acquisition , and questioned whether property is best left in private or public hands . In the Middle Ages , scholasticists such as Thomas Aquinas argued that it was a moral obligation of businesses to sell goods at a just price .   In the Western world , economics was not a separate discipline , but part of philosophy until the 18th -- 19th century Industrial Revolution and the 19th century Great Divergence , which accelerated economic growth . Long before that , from the Renaissance at least , economics as an intellectual discipline or science was dominated by Western thinkers and their academic institutions , schooling economists from outside the West , although there are isolated instances in other societies .


History of the world

The history of the world ( or world history ) describes the history of humanity ( or human history ) as determined by the study of archaeological and written records , beginning with the invention of writing .   The roots of civilization reach back to the earliest introduction of primitive technology and culture , while Prehistory begins in the Palaeolithic Era , or `` Early Stone Age '' , which is followed by the Neolithic Era , or `` New Stone Age '' , and the Agricultural Revolution ( between 8000 and 5000 BCE ) in the Fertile Crescent . The latter period marked a change in human history , as humans began the systematic husbandry of plants and animals . Agriculture advanced , and most humans transitioned from a nomadic to a settled lifestyle as farmers in permanent settlements . Nomadism continued in some locations , especially in isolated regions with few domesticable plant species , but the relative security and increased productivity provided by farming allowed human communities to expand into increasingly larger units , fostered by advances in transportation .   As farming developed , grain agriculture became more sophisticated and prompted a division of labour to store food between growing seasons . Labour divisions then led to the rise of a leisured upper class and the development of cities . The growing complexity of human societies necessitated systems of writing and accounting . Many cities developed on the banks of lakes and rivers as early as 3000 BCE , when some of the first prominent , well-developed settlements had arisen in Mesopotamia ( `` the Land between the Rivers '' ) , on the banks of Egypt 's Nile River , in the Indus River valley , and along the rivers of China .   The history of the Old World ( particularly Europe and the Mediterranean ) is commonly divided into ancient history ( or `` Antiquity '' ) , up to 476 CE ; post-classical history ( or `` the Middle Ages '' ) , from the 5th through 15th centuries , including the rise of Christianity , the Islamic Golden Age ( c. 750 CE -- c. 1258 CE ) and the early Italian Renaissance ( beginning around 1300 CE ) ; the early modern period , from the 15th century to the late 18th , including the Age of Enlightenment ; and the late modern period , from the Industrial Revolution to the present , including contemporary history .   In the mid-15th century , the invention of modern printing , employing movable type , revolutionized communication , helping end the Middle Ages and ushering in the Scientific Revolution . By the 18th century , the accumulation of knowledge and technology , especially in Europe , had reached a critical mass that brought about the Industrial Revolution . Outside the Old World , including ancient China and ancient India , historical timelines unfolded differently . However , by the 18th century , due to extensive world trade and colonization , the histories of most civilizations had become substantially intertwined ( see `` Globalization '' ) . In the last quarter-millennium , the rates of growth of population , knowledge , technology , communications , commerce , weapons destructiveness and environmental degradation have greatly accelerated , creating opportunities and perils that now confront the planet 's human communities .


Hitler Diaries

The Hitler Diaries ( Hitler-Tagebücher ) were a series of sixty volumes of journals purportedly by Adolf Hitler , but forged by Konrad Kujau between 1981 and 1983 . The diaries were purchased in 1983 for 9.3 million Deutsche Marks ( $ 4.7 million ) by the West German news magazine Stern , which sold serialisation rights to several news organisations . One of the publications involved was The Sunday Times , who asked their independent director , the historian Hugh Trevor-Roper , to authenticate the diaries ; he did so , pronouncing them genuine . At the press conference to announce the forthcoming publication , Trevor-Roper announced that on reflection he had changed his mind , and other historians also raised questions concerning their validity . Rigorous forensic analysis , which had not been performed previously , quickly confirmed that the diaries were fakes .   Kujau , born and brought up in East Germany , had a history of petty crime and deception . In the mid-1970s he began selling Nazi memorabilia which he was smuggling from the East , but soon found he could raise the prices by forging additional authentication details which linked ordinary souvenirs to the Nazi leaders . He began forging paintings by Hitler and an increasing number of notes , poems and letters , until he produced his first diary in the mid - to late 1970s . The West German journalist with Stern who `` discovered '' the diaries and was involved in their purchase was Gerd Heidemann , who had an obsession with the Nazis . When Stern started buying the diaries , Heidemann stole a significant proportion of the money provided .   Kujau and Heidemann both spent time in prison for their parts in the fraud , and several newspaper editors lost their jobs . The story of the scandal has been the basis of various films : Selling Hitler ( 1991 ) for the British ITV channel , Schtonk ! ( 1992 ) for German cinema , and History 's Greatest Hoaxes : The Hitler Diaries . ( 2016 ) a documentary produced by Like a Shot Entertainment Ltd. in association with UKTV and Yesterday .


Hockey stick controversy

In the hockey stick controversy , the data and methods used in reconstructions of the temperature record of the past 1000 years have been disputed . Reconstructions have consistently shown that the rise in the instrumental temperature record of the past 150 years is not matched in earlier centuries , and the name `` hockey stick graph '' was coined for figures showing a long-term decline followed by an abrupt rise in temperatures . These graphs were publicised to explain the scientific findings of climatology , and in addition to scientific debate over the reconstructions , they have been the topic of political dispute . The issue is part of the global warming controversy and has been one focus of political responses to reports by the Intergovernmental Panel on Climate Change ( IPCC ) . Arguments over the reconstructions have been taken up by fossil fuel industry funded lobbying groups attempting to cast doubt on climate science .   The use of proxy indicators to get quantitative estimates of the temperature record of past centuries was developed from the 1990s onwards , and found indications that recent warming was exceptional . The reconstruction introduced the `` Composite Plus Scaling '' ( CPS ) method used by most later large-scale reconstructions , and its findings were disputed by Patrick Michaels at the United States House Committee on Science .   In 1998 , Michael E. Mann , Raymond S. Bradley and Malcolm K. Hughes developed new statistical techniques to produce ( MBH98 ) , the first eigenvector-based climate field reconstruction ( CFR ) . This showed global patterns of annual surface temperature , and included a graph of average hemispheric temperatures back to 1400 . In ( MBH99 ) the methodology was extended back to 1000 . The term hockey stick was coined by the climatologist Jerry D. Mahlman , to describe the pattern this showed , envisaging a graph that is relatively flat to 1900 as forming an ice hockey stick 's `` shaft '' , followed by a sharp increase corresponding to the `` blade '' .  A version of this graph was featured prominently in the 2001 IPCC Third Assessment Report ( TAR ) , along with four other reconstructions supporting the same conclusion . The graph was publicised , and became a focus of dispute for those opposed to the strengthening scientific consensus that late 20th-century warmth was exceptional .   Those disputing the graph included Pat Michaels , the George C. Marshall Institute and Fred Singer . A paper by Willie Soon and Sallie Baliunas claiming greater medieval warmth was used by the Bush administration chief of staff Philip Cooney to justify altering the first Environmental Protection Agency Report on the Environment . The paper was quickly dismissed by scientists in the Soon and Baliunas controversy , but on July 28 , Republican Jim Inhofe spoke in the Senate citing it to claim `` that man-made global warming is the greatest hoax ever perpetrated on the American people '' .   Later in 2003 , a paper by Steve McIntyre and Ross McKitrick disputing the data used in MBH98 paper was publicised by the George C. Marshall Institute and the Competitive Enterprise Institute . In 2004 , Hans von Storch published criticism of the statistical techniques as tending to underplay variations in earlier parts of the graph , though this was disputed and he later accepted that the effect was very small . In 2005 , McIntyre and McKitrick published criticisms of the principal component analysis methodology as used in MBH98 and MBH99 . The analysis therein was subsequently disputed by published papers , including and , which pointed to errors in the McIntyre and McKitrick methodology . In June 2005 , Rep. Joe Barton launched what Sherwood Boehlert , chairman of the House Science Committee , called a `` misguided and illegitimate investigation '' into the data , methods and personal information of Mann , Bradley and Hughes . At Boehlert 's request , a panel of scientists convened by the National Research Council was set up , which reported in 2006 , supporting Mann 's findings with some qualifications , including agreeing that there were some statistical failings but these had little effect on the result . Barton and U.S. Rep. Ed Whitfield requested Edward Wegman to set up a team of statisticians to investigate , and they supported McIntyre and McKitrick 's view that there were statistical failings , although they did not quantify whether there was any significant effect . They also produced an extensive network analysis which has been discredited by expert opinion and found to have issues of plagiarism . Arguments against the MBH studies were reintroduced as part of the Climatic Research Unit email controversy , but dismissed by eight independent investigations .   More than two dozen reconstructions , using various statistical methods and combinations of proxy records , have supported the broad consensus shown in the original 1998 hockey-stick graph , with variations in how flat the pre-20th century `` shaft '' appears . The 2007 IPCC Fourth Assessment Report cited 14 reconstructions , 10 of which covered 1,000 years or longer , to support its strengthened conclusion that it was likely that Northern Hemisphere temperatures during the 20th century were the highest in at least the past 1,300 years . Over a dozen subsequent reconstructions , including Mann et al. 2008 and , have supported these general conclusions .