Brown bear

The brown bear ( Ursus arctos ) is a large bear with the widest distribution of any living ursid . The species is distributed across much of northern Eurasia and North America . It is one of the two largest terrestrial carnivorans alive today , rivaled in body size only by its close cousin , the polar bear ( Ursus maritimus ) , which is much less variable in size and averages larger due to this . There are several recognized subspecies , many of which are quite well-known within their native ranges , found in the brown bear species .   The brown bear 's principal range includes parts of Russia , Central Asia , China , Canada , the United States ( mostly Alaska ) , Scandinavia and the Carpathian region ( especially Romania ) , Anatolia , and Caucasus . The brown bear is recognized as a national and state animal in several European countries .   While the brown bear 's range has shrunk and it has faced local extinctions , it remains listed as a least concern species by the International Union for Conservation of Nature ( IUCN ) with a total population of approximately 200,000 . As of 2012 , this and the American black bear are the only bear species not classified as threatened by the IUCN . However , the Californian , North African ( Atlas bear ) , and Mexican subspecies were hunted to extinction in the nineteenth and early twentieth centuries , and many of the southern Asian subspecies are highly endangered . One of the smaller-bodied subspecies , the Himalayan brown bear , is critically endangered , occupying only 2 % of its former range and threatened by uncontrolled poaching for its parts . The Marsican brown bear , one of several currently isolated populations of the main Eurasian brown bear race , in central Italy is believed to have a population of just 30 to 40 bears .


Buffalo meat

Buffalo meat is the meat of the water buffalo , a large bovid , raised for its milk and meat in many countries including India , Nepal , Pakistan , Bangladesh , Bulgaria , Italy , Russia , Czech Republic , Slovakia and Egypt .   Buffalo meat is known by various names in different countries . In some places it is known as buffen , or buff in Nepal ; in some countries it is known as carabeef , from the Spanish term and breed name carabao . Meat taken from a buffalo younger than 20 months is known as padwa in India and Pakistan or pado in Nepal . Buffalo calves are often referred to as buffalo broilers and brought up exclusively on milk for the purpose of being slaughtered young for meat .


Burkina Faso

Burkina Faso ( -LSB- usbər ` kiːnə _ , fɑːsoʊ -RSB- ; -LSB- buʁkina faso -RSB- ) is a landlocked country located in West Africa . It covers an area of around 274200 km2 and is surrounded by six countries : Mali to the north ; Niger to the east ; Benin to the southeast ; Togo and Ghana to the south ; and Ivory Coast to the southwest . Its capital is Ouagadougou . In 2014 its population was estimated at just over 17.3 million . Burkina Faso is a francophone country and French is an official language of government and business . Formerly called the Republic of Upper Volta , the country was renamed `` Burkina Faso '' on 4 August 1984 by then-President Thomas Sankara . The citizens of Burkina Faso are known as Burkinabé ( -LSB- bərˈkiːnəbeɪ -RSB- ) .   The northwestern part of present-day Burkina Faso was populated by hunter-gatherers from 14,000 BC to 5,000 BC . From the 3rd to the 13th centuries AD , the Iron-Age Bura culture was situated in the territory of present-day southeastern Burkina Faso and southwestern Niger . Various ethnic groups of present-day Burkina Faso , such as the Mossi , Fula and Dyula , arrived in successive waves between the 8th and 15th centuries . From the 11th century the Mossi people established several separate kingdoms . In the 1890s during the European Scramble for Africa , the territory of Burkina Faso was invaded by France , and colonial control was established following a war of conquest between 1896 to 1904 . The territory was made part of French West Africa in 1904 , and the colony of French Upper Volta was established on 1 March 1919 . The colony was named for its location on the upper courses of the Volta River ( the Black , Red and White Volta ) .   The Republic of Upper Volta was established on 11 December 1958 as a self-governing colony within the French Community , and on 5 August 1960 it gained full independence , with Maurice Yaméogo as President . After protests by students and labour unions , Yaméogo was deposed in the 1966 coup d'état led by Sangoulé Lamizana , who became President . His rule coincided with the Sahel drought and famine , and facing problems from the country 's traditionally powerful trade unions , he was deposed in the 1980 coup d'état led by Saye Zerbo . Encountering resistance from trade unions once again , Zerbo 's government was overthrown in the 1982 coup d'état led by Jean-Baptiste Ouédraogo . The leader of the leftist faction of Ouédraogo 's government , Thomas Sankara , became Prime Minister but was imprisoned . Efforts to free him led to the popularly-supported 1983 coup d'état , in which he became President . Sankara renamed the country to Burkina Faso and launched an ambitious socioeconomic programme which included a nationwide literacy campaign , land redistribution to peasants , railway and road construction and the outlawing of female genital mutilation , forced marriages and polygamy . Sankara was overthrown and killed in the 1987 coup d'état led by Blaise Compaoré -- deteriorating relations with the former coloniser France and its ally the Ivory Coast was the reason given for the coup .   In 1987 Blaise Compaoré became President and , after an alleged 1989 coup attempt , was later elected in 1991 and 1998 , elections which were boycotted by the opposition and received a considerably low turnout , and in 2005 . He remained head of state until he was ousted from power by the popular youth upheaval of 31 October 2014 . He then fled to the Ivory Coast . Michel Kafando subsequently became the transitional President of the country . On 16 September 2015 a military coup d'état against the Kafando government was carried out by the Regiment of Presidential Security . On 24 September 2015 , after pressure from the African Union , ECOWAS and the armed forces , the military junta agreed to step down , and Michel Kafando was reinstated as Acting President . In the general election held on 29 November 2015 , Roch Marc Christian Kaboré won in the first round with 53.5 % of the vote and was sworn in as President on 29 December 2015 .


Bushfires in Australia

Bushfires in Australia are frequent events during the warmer months of the year , due to Australia 's mostly hot , dry climate . Each year , such fires impact extensive areas . On one hand , they can cause property damage and loss of human life . On the other hand , certain native flora in Australia have evolved to rely on bushfires as a means of reproduction , and fire events are an interwoven and an essential part of the ecology of the continent . For thousands of years , Indigenous Australians have used fire to foster grasslands for hunting and to clear tracks through dense vegetation .   Major firestorms that result in severe loss of life are often named based on the day on which they occur , such as Ash Wednesday and Black Saturday . Some of the most intense , extensive and deadly bushfires commonly occur during droughts and heat waves , such as the 2009 Southern Australia heat wave , which precipitated the conditions during the 2009 Black Saturday bushfires in which 173 people lost their lives . Other major conflagrations include the 1983 Ash Wednesday bushfires , the 2003 Eastern Victorian alpine bushfires and the 2006 December Bushfires .   Global warming is increasing the frequency and severity of bushfires .


CLOUD experiment

Cosmics Leaving Outdoor Droplets or CLOUD is an experiment being run at CERN by a group of researchers led by Jasper Kirkby to investigate the microphysics between galactic cosmic rays ( GCRs ) and aerosols under controlled conditions . The experiment began operation in November 2009 .   The primary goal is to understand the influence of galactic cosmic rays ( GCRs ) on aerosols and clouds , and their implications for climate . Although its design is optimised to address the cosmic ray question , ( as posed by Henrik Svensmark and colleagues in 1997 ) CLOUD allows as well to measure aerosol nucleation and growth under controlled laboratory conditions . Atmospheric aerosols and their effect on clouds are recognised by the IPCC as main source of uncertainty in present radiative forcing and climate models .


Caffeine

Caffeine is a central nervous system ( CNS ) stimulant of the methylxanthine class . It is the world 's most widely consumed psychoactive drug . Unlike many other psychoactive substances , it is legal and unregulated in nearly all parts of the world . There are several known mechanisms of action to explain the effects of caffeine . The most prominent is that it reversibly blocks the action of adenosine on its receptor and consequently prevents the onset of drowsiness induced by adenosine . Caffeine also stimulates certain portions of the autonomic nervous system .   Caffeine is a bitter , white crystalline purine , a methylxanthine alkaloid , and is chemically related to the adenine and guanine bases of deoxyribonucleic acid ( DNA ) and ribonucleic acid ( RNA ) . It is found in the seeds , nuts , or leaves of a number of plants native to South America and East Asia and helps to protect them against predator insects and to prevent germination of nearby seeds . The most well known source of caffeine is the coffee bean , a misnomer for the seed of Coffea plants . Beverages containing caffeine are ingested to relieve or prevent drowsiness and to improve performance . To make these drinks , caffeine is extracted by steeping the plant product in water , a process called infusion . Caffeine-containing drinks , such as coffee , tea , and cola , are very popular ; in 2005 , 90 % of North American adults consumed caffeine daily .   Caffeine can have both positive and negative health effects . It can treat and prevent the premature infant breathing disorders bronchopulmonary dysplasia of prematurity and apnea of prematurity . Caffeine citrate is on the WHO Model List of Essential Medicines . It may confer a modest protective effect against some diseases , including Parkinson 's disease and certain types of cancer . One meta-analysis concluded that cardiovascular disease such as coronary artery disease and stroke is less likely with 3 -- 5 cups of non-decaffeinated coffee per day but more likely with over 5 cups per day . Some people experience insomnia or sleep disruption if they consume caffeine , especially during the evening hours , but others show little disturbance . Evidence of a risk during pregnancy is equivocal ; some authorities recommend that pregnant women limit consumption to the equivalent of two cups of coffee per day or less . Caffeine can produce a mild form of drug dependence -- associated with withdrawal symptoms such as sleepiness , headache , and irritability -- when an individual stops using caffeine after repeated daily intake . Tolerance to the autonomic effects of increased blood pressure and heart rate , and increased urine output , develops with chronic use ( i.e. , these symptoms become less pronounced or do not occur following consistent use ) .   Caffeine is classified by the Food and Drug Administration as `` generally recognized as safe '' ( GRAS ) . Toxic doses , over 10 grams per day for an adult , are much higher than typical doses of under 500 milligrams per day . A cup of coffee contains 80 -- 175 mg of caffeine , depending on what `` bean '' ( seed ) is used and how it is prepared ( e.g. drip , percolation , or espresso ) . Thus it requires roughly 50 -- 100 ordinary cups of coffee to reach a lethal dose . However pure powdered caffeine , which is available as a dietary supplement , can be lethal in tablespoon-sized amounts .


Calcium carbonate

Calcium carbonate is a chemical compound with the formula CaCO3 . It is a common substance found in rocks as the minerals calcite and aragonite ( most notably as limestone , which contains both of those minerals ) and is the main component of pearls and the shells of marine organisms , snails , and eggs . Calcium carbonate is the active ingredient in agricultural lime and is created when calcium ions in hard water react with carbonate ions to create limescale . It is medicinally used as a calcium supplement or as an antacid , but excessive consumption can be hazardous .


California

California ( -LSB- kælᵻˈfɔːrnjə , _ - ni.ə -RSB- , ) is the most populous state in the United States and the third most extensive by area . Located on the western ( Pacific Ocean ) coast of the U.S. , California is bordered by the other U.S. states of Oregon , Nevada , and Arizona and shares an international border with the Mexican state of Baja California . The state capital is Sacramento . Los Angeles is California 's most populous city , and the country 's second largest after New York City . The Greater Los Angeles Area and the San Francisco Bay Area are the nation 's second - and fifth-most populous urban regions , respectively . California also has the nation 's most populous county , Los Angeles County , and its largest county by area , San Bernardino County .   California 's diverse geography ranges from the Pacific Coast in the west to the Sierra Nevada mountain range in the east ; and from the redwood -- Douglas fir forests in the northwest to the Mojave Desert in the southeast . The Central Valley , a major agricultural area , dominates the state 's center . Though California is well-known for its warm Mediterranean climate , the large size of the state means it can vary from moist temperate rainforest in the north , to arid desert in the interior , as well as snowy alpine in the mountains .   What is now California was first settled by various Native American tribes before being explored by a number of European expeditions during the 16th and 17th centuries . The Spanish Empire then claimed it as part of Alta California in their New Spain colony . The area became a part of Mexico in 1821 following its successful war for independence , but was ceded to the United States in 1848 after the Mexican -- American War . The western portion of Alta California then was organized as the State of California , and admitted as the 31st state on September 9 , 1850 . The California Gold Rush starting in 1848 led to dramatic social and demographic changes , with large-scale emigration from the east and abroad with an accompanying economic boom .   If it were a country , California would be the 6th largest economy in the world and the 35th most populous . It is also regarded as a global trendsetter in both popular culture and politics , and is the origin of the film industry , the hippie counterculture , the Internet , and the personal computer , among others . Fifty-eight percent of the state 's economy is centered on finance , government , real estate services , technology , and professional , scientific and technical business services . The San Francisco Bay Area has the nation 's highest median household income by metropolitan area , and is the headquarters of three of the world 's largest 40 firms by revenue , Chevron , Apple , and McKesson . Although it accounts for only 1.5 percent of the state 's economy , California 's agriculture industry has the highest output of any U.S. state .


Cambrian

The Cambrian Period ( -LSB- pronˈkæmbriən -RSB- or -LSB- ˈkeɪmbriən -RSB- ) was the first geological period of the Paleozoic Era , of the Phanerozoic Eon . The Cambrian lasted 55.6 million years from the end of the preceding Ediacaran Period 541 million years ago ( mya ) to the beginning of the Ordovician Period mya . Its subdivisions , and its base , are somewhat in flux . The period was established ( as `` Cambrian series '' ) by Adam Sedgwick , who named it after Cambria , the Latinised form of Cymru , the Welsh name for Wales , where Britain 's Cambrian rocks are best exposed . The Cambrian is unique in its unusually high proportion of lagerstätte sedimentary deposits , sites of exceptional preservation where `` soft '' parts of organisms are preserved as well as their more resistant shells . As a result , our understanding of the Cambrian biology surpasses that of some later periods .   The Cambrian marked a profound change in life on Earth ; prior to the Cambrian , the majority of living organisms on the whole were small , unicellular and simple ; the Precambrian Charnia being exceptional . Complex , multicellular organisms gradually became more common in the millions of years immediately preceding the Cambrian , but it was not until this period that mineralized -- hence readily fossilized -- organisms became common . The rapid diversification of lifeforms in the Cambrian , known as the Cambrian explosion , produced the first representatives of all modern animal phyla . Phylogenetic analysis has supported the view that during the Cambrian radiation , metazoa ( animals ) evolved monophyletically from a single common ancestor : flagellated colonial protists similar to modern choanoflagellates .   Although diverse life forms prospered in the oceans , the land was comparatively barren -- with nothing more complex than a microbial soil crust and a few molluscs that emerged to browse on the microbial biofilm . Most of the continents were probably dry and rocky due to a lack of vegetation . Shallow seas flanked the margins of several continents created during the breakup of the supercontinent Pannotia . The seas were relatively warm , and polar ice was absent for much of the period .   The United States Federal Geographic Data Committee uses a `` barred capital C '' character similar to the capital letter Ukrainian Ye to represent the Cambrian Period .  The proper Unicode character is .


Cambridge, Massachusetts

Cambridge ( -LSB- ˈkeɪmbrɪdʒ -RSB- ) is a city in Middlesex County , Massachusetts , and is a part of the Boston metropolitan area .   Situated directly north of the city of Boston , across the Charles River , it was named in honor of the University of Cambridge in the United Kingdom , an important center of the Puritan theology embraced by the town 's founders . Harvard University and the Massachusetts Institute of Technology ( MIT ) , two of the world 's most prestigious universities , are located in Cambridge , as was Radcliffe College , one of the leading colleges for women in the United States until it merged with Harvard .   According to the 2010 Census , the city 's population was 105,162 . , it was the fifth most populous city in the state , behind Boston , Worcester , Springfield and Lowell . Cambridge was one of the two seats of Middlesex County prior to the abolition of county government in 1997 ; Lowell was the other .   Kendall Square in Cambridge has been called `` the most innovative square mile on the planet '' , in reference to the high concentration of entrepreneurial start-ups and quality of innovation which have emerged in the vicinity of the square since 2010 .


Canada

Canada ( -LSB- ˈkænədə -RSB- -LSB- kanadɑ -RSB- ) is a country in the northern part of North America . Its ten provinces and three territories extend from the Atlantic to the Pacific and northward into the Arctic Ocean , covering 9.98 e6km2 , making it the world 's second-largest country by total area and the fourth-largest country by land area . Canada 's border with the United States is the world 's longest binational land border . The majority of the country has a cold or severely cold winter climate , but southerly areas are warm in summer . Canada is sparsely populated , the majority of its land territory being dominated by forest and tundra and the Rocky Mountains . It is highly urbanized with 82 per cent of the 35.15 million people concentrated in large and medium-sized cities , many near the southern border . One third of the population lives in the three largest cities : Toronto , Montreal and Vancouver . Its capital is Ottawa , and other major urban areas include Calgary , Edmonton , Quebec City , Winnipeg and Hamilton .   Various aboriginal peoples had inhabited what is now Canada for thousands of years prior to European colonization . Beginning in the 16th century , British and French claims were made on the area , with the colony of Canada first being established by the French in 1535 during Jacques Cartier 's second voyage to New France . As a consequence of various conflicts , Great Britain gained and lost territories within British North America until it was left , in the late 18th century , with what mostly geographically comprises Canada today . Pursuant to the British North America Act , on July 1 , 1867 , the colonies of Canada , New Brunswick , and Nova Scotia joined to form the semi-autonomous federal Dominion of Canada . This began an accretion of provinces and territories to the mostly self-governing Dominion to the present ten provinces and three territories forming modern Canada .   In 1931 , Canada achieved near total independence from the United Kingdom with the Statute of Westminster 1931 , but at the time , Canada decided to allow the British Parliament to temporarily retain the power to amend Canada 's constitution , on request from the Parliament of Canada . With the Constitution Act 1982 , Canada took over that authority ( as the conclusion of Patriation ) , removing the last remaining ties of legal dependence on the Parliament of the United Kingdom , giving the country full sovereignty .   Canada is a federal parliamentary democracy and a constitutional monarchy , with Queen Elizabeth II being the head of state . The country is officially bilingual at the federal level . It is one of the world 's most ethnically diverse and multicultural nations , the product of large-scale immigration from many other countries . Its advanced economy is the eleventh largest in the world , relying chiefly upon its abundant natural resources and well-developed international trade networks . Canada 's long and complex relationship with the United States has had a significant impact on its economy and culture .   Canada is a developed country and has the tenth highest nominal per capita income globally as well as the ninth highest ranking in the Human Development Index . It ranks among the highest in international measurements of government transparency , civil liberties , quality of life , economic freedom , and education . Canada is a Commonwealth realm member of the Commonwealth of Nations , a member of the Francophonie , and part of several major international and intergovernmental institutions or groupings including the United Nations , the North Atlantic Treaty Organization , the G8 , the Group of Ten , the G20 , the North American Free Trade Agreement and the Asia-Pacific Economic Cooperation forum .


Cancer

Cancer is a group of diseases involving abnormal cell growth with the potential to invade or spread to other parts of the body . Not all tumors are cancerous ; benign tumors do not spread to other parts of the body . Possible signs and symptoms include a lump , abnormal bleeding , prolonged cough , unexplained weight loss and a change in bowel movements . While these symptoms may indicate cancer , they may have other causes . Over 100 types of cancers affect humans .   Tobacco use is the cause of about 22 % of cancer deaths . Another 10 % is due to obesity , poor diet , lack of physical activity , and excessive drinking of alcohol . Other factors include certain infections , exposure to ionizing radiation and environmental pollutants . In the developing world nearly 20 % of cancers are due to infections such as hepatitis B , hepatitis C and human papillomavirus ( HPV ) . These factors act , at least partly , by changing the genes of a cell . Typically many genetic changes are required before cancer develops . Approximately 5 -- 10 % of cancers are due to inherited genetic defects from a person 's parents . Cancer can be detected by certain signs and symptoms or screening tests . It is then typically further investigated by medical imaging and confirmed by biopsy .   Many cancers can be prevented by not smoking , maintaining a healthy weight , not drinking too much alcohol , eating plenty of vegetables , fruits and whole grains , vaccination against certain infectious diseases , not eating too much processed and red meat , and avoiding too much sunlight exposure . Early detection through screening is useful for cervical and colorectal cancer . The benefits of screening in breast cancer are controversial . Cancer is often treated with some combination of radiation therapy , surgery , chemotherapy , and targeted therapy . Pain and symptom management are an important part of care . Palliative care is particularly important in people with advanced disease . The chance of survival depends on the type of cancer and extent of disease at the start of treatment . In children under 15 at diagnosis the five-year survival rate in the developed world is on average 80 % . For cancer in the United States the average five-year survival rate is 66 % .   In 2015 about 90.5 million people had cancer . About 14.1 million new cases occur a year ( not including skin cancer other than melanoma ) . It caused about 8.8 million deaths ( 15.7 % ) of human deaths . The most common types of cancer in males are lung cancer , prostate cancer , colorectal cancer and stomach cancer . In females , the most common types are breast cancer , colorectal cancer , lung cancer and cervical cancer . If skin cancer other than melanoma were included in total new cancers each year it would account for around 40 % of cases . In children , acute lymphoblastic leukaemia and brain tumors are most common except in Africa where non-Hodgkin lymphoma occurs more often . In 2012 , about 165,000 children under 15 years of age were diagnosed with cancer . The risk of cancer increases significantly with age and many cancers occur more commonly in developed countries . Rates are increasing as more people live to an old age and as lifestyle changes occur in the developing world . The financial costs of cancer were estimated at $ 1.16 trillion US dollars per year as of 2010 .


Cannabis cultivation

This article presents common techniques and facts regarding the cultivation of the flowering plant Cannabis , primarily for the production and consumption of cannabis flowers ( `` buds '' ) . Cultivation techniques for other purposes ( such as hemp production ) differ .


Captain America: The First Avenger

Captain America : The First Avenger is a 2011 American superhero film based on the Marvel Comics character Captain America , produced by Marvel Studios and distributed by Paramount Pictures . It is the fifth film in the Marvel Cinematic Universe . The film was directed by Joe Johnston , written by Christopher Markus & Stephen McFeely , and stars Chris Evans , Tommy Lee Jones , Hugo Weaving , Hayley Atwell , Sebastian Stan , Dominic Cooper , Neal McDonough , Derek Luke , and Stanley Tucci . Set predominantly during World War II , Captain America : The First Avenger tells the story of Steve Rogers , a sickly man from Brooklyn who is transformed into super-soldier Captain America and must stop the Red Skull , who intends to use an artifact called the `` Tesseract '' as an energy-source for world domination .   Captain America : The First Avenger began as a concept in 1997 and was scheduled for distribution by Artisan Entertainment . However , a lawsuit , not settled until September 2003 , disrupted the project . In 2005 , Marvel Studios received a loan from Merrill Lynch , and planned to finance and release it through Paramount Pictures . Directors Jon Favreau and Louis Leterrier were interested in directing the project before Johnston was approached in 2008 . The principal characters were cast between March and June 2010 . Production of Captain America : The First Avenger began in June 2010 , and filming took place in London , Manchester , Caerwent , and Liverpool in the United Kingdom , and Los Angeles in the United States . The film was converted to 3D in post-production .   Captain America : The First Avenger premiered in Hollywood on July 19 , 2011 , and was released in the United States on July 22 , 2011 . The film received positive reviews and was commercially successful , grossing over $ 370 million worldwide . The Blu-ray and DVD were released on October 25 , 2011 . A sequel titled Captain America : The Winter Soldier was released on April 4 , 2014 , and a third film titled Captain America : Civil War was released on May 6 , 2016 .


Captain Cold

Captain Cold ( Leonard Snart ) is a fictional character appearing in American comic books published by DC Comics . Captain Cold is the leader of the Rogues , a loose criminal association , , as well as the older brother of Golden Glider . He also has served as a bitter enemy to the Silver Age Flash Barry Allen , both enemy and grudging friend to the third Flash Wally West , and one of the killers of the fourth Flash Bart Allen .   IGN 's list of the Top 100 Comic Book Villains Of All Time List ranked Captain Cold as # 27 . Actor Wentworth Miller has portrayed the character in The CW 's live action Arrowverse .


Captain Planet and the Planeteers

Captain Planet and the Planeteers is an American animated environmentalist television program created by Ted Turner and Barbara Pyle . The series was produced by Turner Program Services and DIC Entertainment and it was broadcast on TBS from September 15 , 1990 , to December 5 , 1992 . A sequel series , The New Adventures of Captain Planet , was produced by Hanna-Barbera and Turner Program Services and was broadcast from September 11 , 1993 , to May 11 , 1996 . Both series continue today in syndication . The program is a form of edutainment and advocates environmentalism and is famous for having a number of famous actors providing voices for the villains .   In February 2009 , Mother Nature Network began airing episodes and unreleased footage of Captain Planet and the Planeteers on its website .


Car

A car ( or automobile ) is a wheeled , self-powered motor vehicle used for transportation and a product of the automotive industry . Most definitions of the term specify that cars are designed to run primarily on roads , to have seating for one to eight people , to typically have four wheels with tyres , and to be constructed principally for the transport of people rather than goods . The year 1886 is regarded as the birth year of the modern car . In that year , German inventor Karl Benz built the Benz Patent-Motorwagen . Cars did not become widely available until the early 20th century . One of the first cars that was accessible to the masses was the 1908 Model T , an American car manufactured by the Ford Motor Company . Cars were rapidly adopted in the United States of America , where they replaced animal-drawn carriages and carts , but took much longer to be accepted in Western Europe and other parts of the world .   Cars are equipped with controls used for driving , parking , passenger comfort and safety , and controlling a variety of lights . Over the decades , additional features and controls have been added to vehicles , making them progressively more complex . Examples include rear reversing cameras , air conditioning , navigation systems , and in car entertainment . Most cars in use in the 2010s are propelled by an internal combustion engine , fueled by deflagration of gasoline ( also known as petrol ) or diesel . Both fuels cause air pollution and are also blamed for contributing to climate change and global warming . Vehicles using alternative fuels such as ethanol flexible-fuel vehicles and natural gas vehicles are also gaining popularity in some countries . Electric cars , which were invented early in the history of the car , began to become commercially available in 2008 .   There are costs and benefits to car use . The costs of car usage include the cost of : acquiring the vehicle , interest payments ( if the car is financed ) , repairs and auto maintenance , fuel , depreciation , driving time , parking fees , taxes , and insurance . The costs to society of car use include : maintaining roads , land use , road congestion , air pollution , public health , health care , and disposing of the vehicle at the end of its life . Road traffic accidents are the largest cause of injury-related deaths worldwide .   The benefits may include on-demand transportation , mobility , independence , and convenience . The societal benefits may include : economic benefits , such as job and wealth creation from car production , sales and maintenance , transportation provision , society well-being derived from leisure and travel opportunities , and revenue generation from the tax opportunities . The ability for humans to move flexibly from place to place has far-reaching implications for the nature of societies . It was estimated in 2014 that the number of cars had risen to over 1.25 billion vehicles , up from the 500 million of 1986 . The numbers are increasing rapidly , especially in China , India and other newly industrialized countries .


Carbon Pollution Reduction Scheme

The Carbon Pollution Reduction Scheme ( or CPRS ) was a cap-and-trade emissions trading scheme for anthropogenic greenhouse gases proposed by the Rudd government , as part of its climate change policy , which had been due to commence in Australia in 2010 . It marked a major change in the energy policy of Australia . The policy began to be formulated in April 2007 , when the federal Labor Party was in Opposition and the six Labor-controlled states commissioned an independent review on energy policy , the Garnaut Climate Change Review , which published a number of reports . After Labor won the 2007 federal election and formed government , it published a Green Paper on climate change for discussion and comment . The Federal Treasury then modelled some of the financial and economic impacts of the proposed CPRS scheme .   The Rudd government published a final White Paper on 15 December 2008 , and announced that legislation was intended to take effect in July 2010 ; but the legislation for the CPRS ( aka ETS ) failed to gain the numbers in the Senate and was twice rejected creating a double dissolution election trigger . A bitter political debate within the Coalition Opposition saw Opposition leader Malcolm Turnbull lose the leadership to the anti-CPRS Tony Abbott . The Rudd government did not call an election and in April 2010 , Rudd deferred plans for the CPRS .   After the 2010 federal election , the Gillard Government was able to get the Carbon Pricing Mechanism ( CPM ) passed into law as part of the Clean Energy Futures Package ( CEF ) in 2011 , and became effective on 1 July 2012 . However , after the 2013 federal election there was a change in government , and the Abbott Government repealed the CEF package on 17 July 2014 . Due to the great deal of policy uncertainty surrounding the scheme , organizations in Australia responded in a rather informal and tepid manner and largely withheld from making any large-scale investments in emissions reductions technology during the scheme 's operation .


Carbon capture and storage

Carbon capture and storage ( CCS ) ( or carbon capture and sequestration ) is the process of capturing waste carbon dioxide from large point sources , such as fossil fuel power plants , transporting it to a storage site , and depositing it where it will not enter the atmosphere , normally an underground geological formation . The aim is to prevent the release of large quantities of into the atmosphere ( from fossil fuel use in power generation and other industries ) . It is a potential means of mitigating the contribution of fossil fuel emissions to global warming and ocean acidification . Although has been injected into geological formations for several decades for various purposes , including enhanced oil recovery , the long term storage of is a relatively new concept . The first commercial example was the Weyburn-Midale Carbon Dioxide Project in 2000 . Other examples include SaskPower 's Boundary Dam and Mississippi Power 's Kemper Project . ` CCS ' can also be used to describe the scrubbing of from ambient air as a climate engineering technique .   An integrated pilot-scale CCS power plant was to begin operating in September 2008 in the eastern German power plant Schwarze Pumpe run by utility Vattenfall , to test the technological feasibility and economic efficiency . CCS applied to a modern conventional power plant could reduce emissions to the atmosphere by approximately 80 -- 90 % compared to a plant without CCS . The IPCC estimates that the economic potential of CCS could be between 10 % and 55 % of the total carbon mitigation effort until year 2100 .   Carbon dioxide can be captured out of air or fossil fuel power plant flue gas using adsorption ( or carbon scrubbing ) , membrane gas separation , or adsorption technologies . Amines are the leading carbon scrubbing technology .  Capturing and compressing may increase the energy needs of a coal-fired CCS plant by 25 -- 40 % . These and other system costs are estimated to increase the cost per watt energy produced by 21 -- 91 % for fossil fuel power plants . Applying the technology to existing plants would be more expensive , especially if they are far from a sequestration site . A 2005 industry report suggests that with successful research , development and deployment ( RD&D ) , sequestered coal-based electricity generation in 2025 may cost less than unsequestered coal-based electricity generation today .   Storage of the is envisaged either in deep geological formations , or in the form of mineral carbonates . Deep ocean storage is not currently considered feasible due to the associated effect of ocean acidification . Geological formations are currently considered the most promising sequestration sites . The National Energy Technology Laboratory ( NETL ) reported that North America has enough storage capacity for more than 900 years worth of carbon dioxide at current production rates . A general problem is that long term predictions about submarine or underground storage security are very difficult and uncertain , and there is still the risk that might leak into the atmosphere .


Carbon credit

A carbon credit is a generic term for any tradable certificate or permit representing the right to emit one tonne of carbon dioxide or the mass of another greenhouse gas with a carbon dioxide equivalent ( tCO2e ) equivalent to one tonne of carbon dioxide .   Carbon credits and carbon markets are a component of national and international attempts to mitigate the growth in concentrations of greenhouse gases ( GHGs ) . One carbon credit is equal to one tonne of carbon dioxide , or in some markets , carbon dioxide equivalent gases . Carbon trading is an application of an emissions trading approach . Greenhouse gas emissions are capped and then markets are used to allocate the emissions among the group of regulated sources .   The goal is to allow market mechanisms to drive industrial and commercial processes in the direction of low emissions or less carbon intensive approaches than those used when there is no cost to emitting carbon dioxide and other GHGs into the atmosphere . Since GHG mitigation projects generate credits , this approach can be used to finance carbon reduction schemes between trading partners and around the world .   There are also many companies that sell carbon credits to commercial and individual customers who are interested in lowering their carbon footprint on a voluntary basis . These carbon offsetters purchase the credits from an investment fund or a carbon development company that has aggregated the credits from individual projects . Buyers and sellers can also use an exchange platform to trade , which is like a stock exchange for carbon credits . The quality of the credits is based in part on the validation process and sophistication of the fund or development company that acted as the sponsor to the carbon project . This is reflected in their price ; voluntary units typically have less value than the units sold through the rigorously validated Clean Development Mechanism .


Carbon cycle

The carbon cycle is the biogeochemical cycle by which carbon is exchanged among the biosphere , pedosphere , geosphere , hydrosphere , and atmosphere of the Earth . Carbon is the main component of biological compounds as well as a major component of many minerals such as limestone . Along with the nitrogen cycle and the water cycle , the carbon cycle comprises a sequence of events that are key to make Earth capable of sustaining life . It describes the movement of carbon as it is recycled and reused throughout the biosphere , as well as long-term processes of carbon sequestration to and release from carbon sinks .   The global carbon budget is the balance of the exchanges ( incomes and losses ) of carbon between the carbon reservoirs or between one specific loop ( e.g. , atmosphere and biosphere ) of the carbon cycle . An examination of the carbon budget of a pool or reservoir can provide information about whether the pool or reservoir is functioning as a source or sink for carbon dioxide . The carbon cycle was initially discovered by Joseph Priestley and Antoine Lavoisier , and popularized by Humphry Davy .


Carbon dioxide

Carbon dioxide ( chemical formula ) is a colorless gas with a density about 60 % higher than that of air ( 1.225 g/L ) that is odorless at normally encountered concentrations . Carbon dioxide consists of a carbon atom covalently double bonded to two oxygen atoms . It occurs naturally in Earth 's atmosphere as a trace gas at a concentration of about 0.04 percent ( 400 ppm ) by volume . Natural sources include volcanoes , hot springs and geysers , and it is freed from carbonate rocks by dissolution in water and acids . Because carbon dioxide is soluble in water , it occurs naturally in groundwater , rivers and lakes , ice caps , glaciers and seawater . It is present in deposits of petroleum and natural gas .   As the source of available carbon in the carbon cycle , atmospheric carbon dioxide is the primary carbon source for life on Earth and its concentration in Earth 's pre-industrial atmosphere since late in the Precambrian has been regulated by photosynthetic organisms and geological phenomena . Plants , algae and cyanobacteria use light energy to photosynthesize carbohydrate from carbon dioxide and water , with oxygen produced as a waste product .   Carbon dioxide is produced by all aerobic organisms when they metabolize carbohydrates and lipids to produce energy by respiration . It is returned to water via the gills of fish and to the air via the lungs of air-breathing land animals , including humans . Carbon dioxide is produced during the processes of decay of organic materials and the fermentation of sugars in bread , beer and winemaking . It is produced by combustion of wood and other organic materials and fossil fuels such as coal , peat , petroleum and natural gas .   It is a versatile industrial material , used , for example , as an inert gas in welding and fire extinguishers , as a pressurizing gas in air guns and oil recovery , as a chemical feedstock and in liquid form as a solvent in decaffeination of coffee and supercritical drying . It is added to drinking water and carbonated beverages including beer and sparkling wine to add effervescence . The frozen solid form of , known as `` dry ice '' is used as a refrigerant and as an abrasive in dry-ice blasting .   Carbon dioxide is the most significant long-lived greenhouse gas in Earth 's atmosphere . Since the Industrial Revolution anthropogenic emissions - primarily from use of fossil fuels and deforestation - have rapidly increased its concentration in the atmosphere , leading to global warming . Carbon dioxide also causes ocean acidification because it dissolves in water to form carbonic acid .


Carbon dioxide in Earth's atmosphere

Carbon dioxide is an important trace gas in Earth 's atmosphere . Currently it constitutes about 0.041 % ( equal to 410 parts per million ; ppm ) by volume of the atmosphere . Despite its relatively small concentration is a potent greenhouse gas and plays a vital role in regulating Earth 's surface temperature through radiative forcing and the greenhouse effect . Reconstructions show that concentrations of in the atmosphere have varied , ranging from as high as 7,000 ppm during the Cambrian period about 500 million years ago to as low as 180 ppm during the Quaternary glaciation of the last two million years .   Carbon dioxide is an integral part of the carbon cycle , a biogeochemical cycle in which carbon is exchanged between the Earth 's oceans , soil , rocks and the biosphere . Plants and other photoautotrophs use solar energy to produce carbohydrate from atmospheric carbon dioxide and water by photosynthesis . Almost all other organisms depend on carbohydrate derived from photosynthesis as their primary source of energy and carbon compounds .   The current episode of global warming is attributed to increasing emissions of and other greenhouse gases into Earth 's atmosphere . The global annual mean concentration of in the atmosphere has increased by more than 40 % since the start of the Industrial Revolution , from 280 ppm , the level it had for the last 10,000 years leading up to the mid-18th century , to 399 ppm as of 2015 . The present concentration is the highest in at least the past 800,000 years and likely the highest in the past 20 million years . The increase has been caused by anthropogenic sources , particularly the burning of fossil fuels and deforestation . The daily average concentration of atmospheric CO2 at Mauna Loa Observatory first exceeded 400 ppm on 10 May 2013 . It is currently rising at a rate of approximately 2 ppm/year and accelerating . An estimated 30 -- 40 % of the released by humans into the atmosphere dissolves into oceans , rivers and lakes , which contributes to ocean acidification .


Carbon dioxide removal

Carbon dioxide removal ( CDR ) methods refers to a number of technologies which reduce the levels of carbon dioxide in the atmosphere . Among such technologies are bio-energy with carbon capture and storage , biochar , direct air capture , ocean fertilization and enhanced weathering . CDR is a different approach than removing CO2 from the stack emissions of large fossil fuel point sources , such as power stations . The latter reduces emission to the atmosphere but can not reduce the amount of carbon dioxide already in the atmosphere . As CDR removes carbon dioxide from the atmosphere , it creates negative emissions , offsetting emissions from small and dispersed point sources such as domestic heating systems , airplanes and vehicle exhausts . It is regarded by some as a form of climate engineering , while other commentators describe it as a form of carbon capture and storage or extreme mitigation . Whether CDR would satisfy common definitions of `` climate engineering '' or `` geoengineering '' usually depends upon the scale on which it would be undertaken .   The likely need for CDR has been publicly expressed by a range of individuals and organizations involved with climate change issues , including IPCC chief Rajendra Pachauri , the UNFCCC executive secretary Christiana Figueres , and the World Watch Institute . Institutions with major programs focusing on CDR include the Lenfest Center for Sustainable Energy at the Earth Institute , Columbia University , and the Climate Decision Making Center , an international collaboration operated out of Carnegie-Mellon University 's Department of Engineering and Public Policy .   The mitigation effectiveness of air capture is limited by societal investment , land use , availability of geologic reservoirs , and leakage . The reservoirs are estimated to be sufficient to for storing at least 545 GtC . Storing 771 GtC would cause an 186 ppm atmospheric reduction . In order to return the atmospheric CO2 content to 350 ppm we need atmospheric reduction of 50 ppm plus an additional 2 ppm per year of current emissions .


Carbon footprint

A carbon footprint is historically defined as the total set of greenhouse gas emissions caused by an individual , event , organisation , or product , expressed as carbon dioxide equivalent .   In most cases , the total carbon footprint can not be exactly calculated because of inadequate knowledge of and data about the complex interactions between contributing processes , especially which including the influence on natural processes storing or releasing carbon dioxide . For this reason , Wright , Kemp , and Williams , have suggested to define the carbon footprint as :   A measure of the total amount of carbon dioxide ( CO2 ) and methane ( CH4 ) emissions of a defined population , system or activity , considering all relevant sources , sinks and storage within the spatial and temporal boundary of the population , system or activity of interest . Calculated as carbon dioxide equivalent using the relevant 100-year global warming potential ( GWP100 ) .   Greenhouse gases ( GHGs ) can be emitted through land clearance and the production and consumption of food , fuels , manufactured goods , materials , wood , roads , buildings , transportation and other services . For simplicity of reporting , it is often expressed in terms of the amount of carbon dioxide , or its equivalent of other GHGs , emitted .   Most of the carbon footprint emissions for the average U.S. household come from `` indirect '' sources , i.e. fuel burned to produce goods far away from the final consumer . These are distinguished from emissions which come from burning fuel directly in one 's car or stove , commonly referred to as `` direct '' sources of the consumer 's carbon footprint .   The concept name of the carbon footprint originates from ecological footprint , discussion , which was developed by Rees and Wackernagel in the 1990s which estimates the number of `` earths '' that would theoretically be required if everyone on the planet consumed resources at the same level as the person calculating their ecological footprint . However , given that ecological footprints are a measure of failure , Anindita Mitra ( CREA , Seattle ) chose the more easily calculated `` carbon footprint '' to easily measure use of carbon , as an indicator of unsustainable energy use . In 2007 , carbon footprint was used as a measure of carbon emissions to develop the energy plan for City of Lynnwood , Washington . Carbon footprints are much more specific than ecological footprints since they measure direct emissions of gases that cause climate change into the atmosphere .   Carbon footprint is one of a family of footprint indicators , which also includes water footprint and land footprint .


Carbon monoxide

Carbon monoxide ( CO ) is a colorless , odorless , and tasteless gas that is slightly less dense than air . It is toxic to hemoglobic animals ( both invertebrate and vertebrate , including humans ) when encountered in concentrations above about 35 ppm , although it is also produced in normal animal metabolism in low quantities , and is thought to have some normal biological functions . In the atmosphere , it is spatially variable and short lived , having a role in the formation of ground-level ozone .   Carbon monoxide consists of one carbon atom and one oxygen atom , connected by a triple bond that consists of two covalent bonds as well as one dative covalent bond . It is the simplest oxocarbon and is isoelectronic with the cyanide anion , the nitrosonium cation and molecular nitrogen . In coordination complexes the carbon monoxide ligand is called carbonyl .


Carbon neutrality

Carbon neutrality , or having a net zero carbon footprint , refers to achieving net zero carbon emissions by balancing a measured amount of carbon released with an equivalent amount sequestered or offset , or buying enough carbon credits to make up the difference . It is used in the context of carbon dioxide releasing processes associated with transportation , energy production , and industrial processes such as production of carbon neutral fuel .   The carbon neutrality concept may be extended to include other greenhouse gases ( GHG ) measured in terms of their carbon dioxide equivalence ( e ) -- the impact a GHG has on the atmosphere expressed in the equivalent amount of CO2 . The term `` climate neutral '' reflects the broader inclusiveness of other greenhouse gases in climate change , even if CO2 is the most abundant , encompassing other greenhouse gases regulated by the Kyoto Protocol , namely : methane ( CH4 ) , nitrous oxide ( N2O ) , hydrofluorocarbons ( HFC ) , perfluorocarbons ( PFC ) , and sulphur hexafluoride ( SF6 ) . Both terms are used interchangeably throughout this article .   The best practice for organizations and individuals seeking carbon neutral status entails reducing and/or avoiding carbon emissions first so that only unavoidable emissions are offset . Carbon neutral status is commonly achieved in two ways :  Balancing carbon dioxide released into the atmosphere from burning fossil fuels , with renewable energy that creates a similar amount of useful energy , so that the carbon emissions are compensated , or alternatively using only renewable energies that do n't produce any carbon dioxide ( also called a post-carbon economy ) .  Carbon offsetting by paying others to remove or sequester 100 % of the carbon dioxide emitted from the atmosphere -- for example by planting trees -- or by funding ` carbon projects ' that should lead to the prevention of future greenhouse gas emissions , or by buying carbon credits to remove ( or ` retire ' ) them through carbon trading . While carbon offsetting is often used alongside energy conservation measures to minimize energy use , the practice is criticized by some .   The concept may be extended to include other greenhouse gases measured in terms of their carbon dioxide equivalence . The phrase was the New Oxford American Dictionary 's Word Of The Year for 2006 .


Carbon offset

A carbon offset is a reduction in emissions of carbon dioxide or greenhouse gases made in order to compensate for or to offset an emission made elsewhere .   Carbon offsets are measured in metric tons of carbon dioxide-equivalent ( CO2e ) and may represent six primary categories of greenhouse gases : carbon dioxide , methane ( CH4 ) , nitrous oxide ( N2O ) , perfluorocarbons ( PFCs ) , hydrofluorocarbons ( HFCs ) , and sulfur hexafluoride ( SF6 ) . One carbon offset represents the reduction of one metric ton of carbon dioxide or its equivalent in other greenhouse gases .   There are two markets for carbon offsets . In the larger , compliance market , companies , governments , or other entities buy carbon offsets in order to comply with caps on the total amount of carbon dioxide they are allowed to emit . This market exists in order to achieve compliance with obligations of Annex 1 Parties under the Kyoto Protocol , and of liable entities under the EU Emission Trading Scheme . In 2006 , about $ 5.5 billion of carbon offsets were purchased in the compliance market , representing about 1.6 billion metric tons of CO2e reductions .   In the much smaller , voluntary market , individuals , companies , or governments purchase carbon offsets to mitigate their own greenhouse gas emissions from transportation , electricity use , and other sources . For example , an individual might purchase carbon offsets to compensate for the greenhouse gas emissions caused by personal air travel . Many companies ( see list ) offer carbon offsets as an up-sell during the sales process so that customers can mitigate the emissions related with their product or service purchase ( such as offsetting emissions related to a vacation flight , car rental , hotel stay , consumer good , etc. ) . In 2008 , about $ 705 million of carbon offsets were purchased in the voluntary market , representing about 123.4 million metric tons of CO2e reductions . Some fuel suppliers in the UK offer fuel which has been carbon offset such as Fuel dyes .   Offsets are typically achieved through financial support of projects that reduce the emission of greenhouse gases in the short - or long-term . The most common project type is renewable energy , such as wind farms , biomass energy , or hydroelectric dams . Others include energy efficiency projects , the destruction of industrial pollutants or agricultural byproducts , destruction of landfill methane , and forestry projects . Some of the most popular carbon offset projects from a corporate perspective are energy efficiency and wind turbine projects .   Carbon offsetting has gained some appeal and momentum mainly among consumers in western countries who have become aware and concerned about the potentially negative environmental effects of energy-intensive lifestyles and economies . The Kyoto Protocol has sanctioned offsets as a way for governments and private companies to earn carbon credits that can be traded on a marketplace . The protocol established the Clean Development Mechanism ( CDM ) , which validates and measures projects to ensure they produce authentic benefits and are genuinely `` additional '' activities that would not otherwise have been undertaken . Organizations that are unable to meet their emissions quota can offset their emissions by buying CDM-approved Certified Emissions Reductions . Emissions from burning fuel , such as red diesel , has pushed one UK fuel supplier to create a carbon offset fuel named Carbon Offset Red Diesel .   Offsets may be cheaper or more convenient alternatives to reducing one 's own fossil-fuel consumption . However , some critics object to carbon offsets , and question the benefits of certain types of offsets .  Due diligence is recommended to help businesses in the assessment and identification of `` good quality '' offsets to ensure offsetting provides the desired additional environmental benefits , and to avoid reputational risk associated with poor quality offsets .   Offsets are viewed as an important policy tool to maintain stable economies and to improve sustainability . One of the hidden dangers of climate change policy is unequal prices of carbon in the economy , which can cause economic collateral damage if production flows to regions or industries that have a lower price of carbon -- unless carbon can be purchased from that area , which offsets effectively permit , equalizing the price .


Carbon price

Carbon pricing -- the method favored by many economists for reducing global-warming emissions -- charges those who emit carbon dioxide ( CO2 ) for their emissions . That charge , called a carbon price , is the amount that must be paid for the right to emit one tonne of CO2 into the atmosphere . Carbon pricing usually takes the form either of a carbon tax or a requirement to purchase permits to emit , generally known as cap-and-trade , but also called `` allowances '' .   Carbon pricing solves the economic problem that , a known greenhouse gas , is what economics calls a negative externality -- a detrimental product that is not priced ( charged for ) by any market . As a consequence of not being priced , there is no market mechanism responsive to the costs of CO2 emitted . The standard economic solution to problems of this type , first proposed by Arthur Pigou in 1920 , is for the product - in this case , CO2 emissions - to be charged at a price equal to the monetary value of the damage caused by the emissions . This should result in the economically optimal ( efficient ) amount of CO2 emissions . Many practical concerns mar the theoretical simplicity of this picture : for example , the exact monetary damage caused by a tonne of CO2 is uncertain .   The economics of carbon pricing is much the same for taxes and cap-and-trade . Both prices are efficient ; they have the same social cost and the same effect on profits if permits are auctioned . However , some economists argue that caps prevent non-price policies , such as renewable energy subsidies , from reducing carbon emissions , while carbon taxes do not . Others argue that an enforced cap is the only way to guarantee that carbon emissions will actually be reduced ; a carbon tax will not prevent those who can afford to do so from continuing to generate emissions .   The choice of pricing approach , a tax or cap-and-trade , has been controversial . A carbon tax is generally favored on economic grounds for its simplicity and stability , while cap-and-trade is often favored on political grounds . Recently ( 2013 − 14 ) economic opinion has been shifting more heavily toward taxes as national policy measures , and toward a neutral carbon-price-commitment position for the purpose of international climate negotiations .


Carbon sequestration

Carbon sequestration is the process involved in carbon capture and the long-term storage of atmospheric carbon dioxide . Carbon sequestration involves long-term storage of carbon dioxide or other forms of carbon to mitigate or defer global warming . It has been proposed as a way to slow the atmospheric and marine accumulation of greenhouse gases , which are released by burning fossil fuels .   Carbon dioxide is naturally captured from the atmosphere through biological , chemical , and physical processes . Artificial processes have been devised to produce similar effects , including large-scale , artificial capture and sequestration of industrially produced using subsurface saline aquifers , reservoirs , ocean water , aging oil fields , or other carbon sinks .


Carbon sink

A carbon sink is a natural or artificial reservoir that accumulates and stores some carbon-containing chemical compound for an indefinite period . The process by which carbon sinks remove carbon dioxide from the atmosphere is known as carbon sequestration . Public awareness of the significance of CO2 sinks has grown since passage of the Kyoto Protocol , which promotes their use as a form of carbon offset . There are also different strategies used to enhance this process .


Carbon tax

A carbon tax is a tax levied on the carbon content of fuels . It is a form of carbon pricing . Carbon is present in every hydrocarbon fuel ( coal , petroleum , and natural gas ) and converted to carbon dioxide and other products when combusted . In contrast , non-combustion energy sources -- wind , sunlight , geothermal , hydropower , and nuclear -- do not convert hydrocarbons to . is a heat-trapping `` greenhouse '' gas which represents a negative externality on the climate system ( see scientific opinion on global warming ) . Since GHG emissions caused by the combustion of fossil fuels are closely related to the carbon content of the respective fuels , a tax on these emissions can be levied by taxing the carbon content of fossil fuels at any point in the product cycle of the fuel .   Carbon tax offers social and economic benefits . It is a tax that increases revenue without significantly altering the economy while simultaneously promoting objectives of climate change policy . The objective of a carbon tax is to reduce the harmful and unfavorable levels of carbon dioxide emissions , thereby decelerating climate change and its negative effects on the environment and human health .   Carbon taxes offer a potentially cost-effective means of reducing greenhouse gas emissions . From an economic perspective , carbon taxes are a type of Pigovian tax . They help to address the problem of emitters of greenhouse gases not facing the full social cost of their actions . Carbon taxes can be a regressive tax , in that they may directly or indirectly affect low-income groups disproportionately . The regressive impact of carbon taxes could be addressed by using tax revenues to favour low-income groups .   A number of countries have implemented carbon taxes or energy taxes that are related to carbon content . Most environmentally related taxes with implications for greenhouse gas emissions in OECD countries are levied on energy products and motor vehicles , rather than on emissions directly .   Opposition to increased environmental regulation such as carbon taxes often centers on concerns that firms might relocate and/or people might lose their jobs . It has been argued , however , that carbon taxes are more efficient than direct regulation and may even lead to higher employment ( see footnotes ) . Many large users of carbon resources in electricity generation , such as the United States , Russia , and China , are resisting carbon taxation .


Carbonic acid

Not to be confused with Carbolic acid , an antiquated name for phenol .   Carbonic acid is a chemical compound with the chemical formula H2CO3 ( equivalently OC ( OH ) 2 ) . It is also a name sometimes given to solutions of carbon dioxide in water ( carbonated water ) , because such solutions contain small amounts of H2CO3 . In physiology , carbonic acid is described as volatile acid or respiratory acid , because it is the only acid excreted as a gas by the lungs . It plays an important role in the bicarbonate buffer system to maintain acid -- base homeostasis .   Carbonic acid , which is a weak acid , forms two kinds of salts , the carbonates and the bicarbonates . In geology , carbonic acid causes limestone to dissolve producing calcium bicarbonate which leads to many limestone features such as stalactites and stalagmites .   It was long believed that carbonic acid could not exist as a pure compound . However , in 1991 it was reported that NASA scientists had succeeded in making solid H2CO3 samples .


Cardiovascular disease

Cardiovascular disease ( CVD ) is a class of diseases that involve the heart or blood vessels . Cardiovascular disease includes coronary artery diseases ( CAD ) such as angina and myocardial infarction ( commonly known as a heart attack ) . Other CVDs include stroke , heart failure , hypertensive heart disease , rheumatic heart disease , cardiomyopathy , heart arrhythmia , congenital heart disease , valvular heart disease , carditis , aortic aneurysms , peripheral artery disease , thromboembolic disease , and venous thrombosis .   The underlying mechanisms vary depending on the disease in question . Coronary artery disease , stroke , and peripheral artery disease involve atherosclerosis . This may be caused by high blood pressure , smoking , diabetes , lack of exercise , obesity , high blood cholesterol , poor diet , and excessive alcohol consumption , among others . High blood pressure results in 13 % of CVD deaths , while tobacco results in 9 % , diabetes 6 % , lack of exercise 6 % and obesity 5 % . Rheumatic heart disease may follow untreated strep throat .   It is estimated that 90 % of CVD is preventable . Prevention of atherosclerosis involves improving risk factors through : healthy eating , exercise , avoidance of tobacco smoke and limiting alcohol intake . Treating risk factors , such as high blood pressure , blood lipids and diabetes is also beneficial . Treating people who have strep throat with antibiotics can decrease the risk of rheumatic heart disease . The effect of the use of aspirin in people who are otherwise healthy is of unclear benefit .   Cardiovascular diseases are the leading cause of death globally . This is true in all areas of the world except Africa . Together they resulted in 17.9 million deaths ( 32.1 % ) in 2015 up from 12.3 million ( 25.8 % ) in 1990 . Deaths , at a given age , from CVD are more common and have been increasing in much of the developing world , while rates have declined in most of the developed world since the 1970s . Coronary artery disease and stroke account for 80 % of CVD deaths in males and 75 % of CVD deaths in females . Most cardiovascular disease affects older adults . In the United States 11 % of people between 20 and 40 have CVD , while 37 % between 40 and 60 , 71 % of people between 60 and 80 , and 85 % of people over 80 have CVD . The average age of death from coronary artery disease in the developed world is around 80 while it is around 68 in the developing world . Disease onset is typically seven to ten years earlier in men as compared to women .


Carl Sagan

Carl Edward Sagan ( -LSB- ˈseɪɡən -RSB- November 9 , 1934 -- December 20 , 1996 ) was an American astronomer , cosmologist , astrophysicist , astrobiologist , author , science popularizer , and science communicator in astronomy and other natural sciences . He is best known for his work as a science popularizer and communicator . His best known scientific contribution is research on extraterrestrial life , including experimental demonstration of the production of amino acids from basic chemicals by radiation . Sagan assembled the first physical messages sent into space : the Pioneer plaque and the Voyager Golden Record , universal messages that could potentially be understood by any extraterrestrial intelligence that might find them . Sagan argued the now accepted hypothesis that the high surface temperatures of Venus can be attributed to and calculated using the greenhouse effect .   Sagan published more than 600 scientific papers and articles and was author , co-author or editor of more than 20 books . He wrote many popular science books , such as The Dragons of Eden , Broca 's Brain and Pale Blue Dot , and narrated and co-wrote the award-winning 1980 television series Cosmos : A Personal Voyage . The most widely watched series in the history of American public television , Cosmos has been seen by at least 500 million people across 60 different countries . The book Cosmos was published to accompany the series . He also wrote the science fiction novel Contact , the basis for a 1997 film of the same name . His papers , containing 595,000 items , are archived at The Library of Congress .   Sagan advocated scientific skeptical inquiry and the scientific method , pioneered exobiology and promoted the Search for Extra-Terrestrial Intelligence ( SETI ) . He spent most of his career as a professor of astronomy at Cornell University , where he directed the Laboratory for Planetary Studies . Sagan and his works received numerous awards and honors , including the NASA Distinguished Public Service Medal , the National Academy of Sciences Public Welfare Medal , the Pulitzer Prize for General Non-Fiction for his book The Dragons of Eden , and , regarding Cosmos : A Personal Voyage , two Emmy Awards , the Peabody Award and the Hugo Award . He married three times and had five children . After suffering from myelodysplasia , Sagan died of pneumonia at the age of 62 , on December 20 , 1996 .


Carlos Curbelo

Carlos Curbelo may refer to :   Carlos Curbelo ( politician ) ( born 1980 ) , American politician  Carlos Curbelo ( footballer ) ( born 1954 ) , former naturalized French footballer


Carnivorous plant

Carnivorous plants are plants that derive some or most of their nutrients ( but not energy ) from trapping and consuming animals or protozoans , typically insects and other arthropods . Carnivorous plants have adapted to grow in places where the soil is thin or poor in nutrients , especially nitrogen , such as acidic bogs and rock outcroppings . Charles Darwin wrote Insectivorous Plants , the first well-known treatise on carnivorous plants , in 1875 .   True carnivory is thought to have evolved independently nine times in five different orders of flowering plants , and is represented by more than a dozen genera . This classification includes at least 583 species that attract , trap and kill prey , absorbing the resulting available nutrients . Additionally , over 300 protocarnivorous plant species in several genera show some but not all of these characteristics .


Cassini–Huygens

Cassini -- Huygens is an unmanned spacecraft sent to the planet Saturn . It is a Flagship-class NASA -- ESA -- ASI robotic spacecraft . Cassini is the fourth space probe to visit Saturn and the first to enter orbit . It has studied the planet and its many natural satellites since arriving there in 2004 .   Development of Cassini began in the 1980s . Its design includes a Saturn orbiter ( Cassini ) and a lander ( Huygens ) for the moon Titan . The two spacecraft are named after astronomers Giovanni Cassini and Christiaan Huygens . The spacecraft was launched on October 15 , 1997 , aboard a Titan IVB/Centaur and entered orbit around Saturn on July 1 , 2004 , after an interplanetary voyage that included flybys of Earth , Venus , and Jupiter . On December 25 , 2004 , Huygens separated from the orbiter , and it landed on Saturn 's moon Titan on January 14 , 2005 . It successfully returned data to Earth , using the orbiter as a relay . This was the first landing ever accomplished in the outer Solar System .   Cassini continued to study the Saturn system in the following years , and continues to operate . Due to a dwindling fuel supply , however , the spacecraft has entered the Grand Finale phase of its mission . A number of risky passes through the gap between Saturn and its inner ring are planned in order to maximize Cassini science returns before the orbiter is intentionally destroyed by diving into Saturn 's atmosphere on September 15 , 2017 . This planned deorbit is necessary to mitigate the risk of the spacecraft eventually colliding with and contaminating one of Saturn 's moons .


Catalan pseudoprime

In mathematics , a Catalan pseudoprime is an odd composite number n satisfying the congruence   where Cm denotes the m-th Catalan number . The congruence also holds for every odd prime number n that justifies the name pseudoprimes for composite numbers n satisfying it .


Cellulosic ethanol

Cellulosic ethanol is ethanol ( ethyl alcohol ) produced from cellulose ( the stringy fiber of a plant ) rather than from the plant 's seeds or fruit . It is a biofuel produced from grasses , wood , algae , or other plants . The fibrous parts of the plants are mostly inedible to animals , including humans , except for ruminants ( grazing , cud-chewing animals such as cows or sheep ) .   Considerable interest in cellulosic ethanol exists because it has the potential for strong economic importance . Growth of cellulose by plants is a mechanism that captures and stores solar energy chemically in nontoxic ways with resultant supplies that are easy to transport and store . Additionally , transport may be unneeded anyway , because grasses or trees can grow almost anywhere temperate . This is why commercially practical cellulosic ethanol is widely viewed as a next level of development for the biofuel industry that could reduce demand for oil and gas drilling and even nuclear power in ways that grain-based ethanol fuel alone can not . Potential exists for the many benefits of carbonaceous liquid fuels and petrochemicals ( which today 's standard of living depends on ) but in a carbon cycle -- balanced and renewable way ( recycling surface and atmosphere carbon instead of pumping underground carbon up into it and thus adding to it ) . Commercially practical cellulosic alcohol could also avoid one of the problems with today 's conventional ( grain-based ) biofuels , which is that they set up competition for grain with food purposes , potentially driving up the price of food . To date , what stands in the way of these goals is that production of cellulosic alcohol is not yet sufficiently practical on a commercial scale .


Celsius

Celsius , also known as centigrade , is a metric scale and unit of measurement for temperature . As an SI derived unit , it is used by most countries in the world . It is named after the Swedish astronomer Anders Celsius ( 1701 -- 1744 ) , who developed a similar temperature scale . The degree Celsius ( ° C ) can refer to a specific temperature on the Celsius scale as well as a unit to indicate a temperature interval , a difference between two temperatures or an uncertainty . Before being renamed to honour Anders Celsius in 1948 , the unit was called centigrade , from the Latin centum , which means 100 , and gradus , which means steps .   The current scale is based on 0 ° for the freezing point of water and 100 ° for the boiling point of water at 1 atm pressure following a change introduced by Jean-Pierre Christin to reverse the Celsius thermometer scale ( from water boiling at 0 degrees and ice melting at 100 degrees ) . This scale is widely taught in schools today . By international agreement the unit `` degree Celsius '' and the Celsius scale are currently defined by two different temperatures : absolute zero , and the triple point of Vienna Standard Mean Ocean Water ( VSMOW ) , a specially purified water . This definition also precisely relates the Celsius scale to the Kelvin scale , which defines the SI base unit of thermodynamic temperature with symbol K. Absolute zero , the lowest temperature possible , is defined as being precisely 0 K and − 273.15 ° C . The temperature of the triple point of water is defined as exactly 273.16 K at 611.657 Pa pressure .   Thus , the magnitude of one degree Celsius and that of one kelvin are exactly the same and the difference between the two scales ' null points is precisely 273.15 degrees ( and ) .


Chaos theory

Chaos theory is a branch of mathematics focused on the behavior of dynamical systems that are highly sensitive to initial conditions . ` Chaos ' is an interdisciplinary theory stating that within the apparent randomness of chaotic complex systems , there are underlying patterns , constant feedback loops , repetition , self-similarity , fractals , self-organization , and reliance on programming at the initial point known as sensitive dependence on initial conditions . The butterfly effect describes how a small change in one state of a deterministic nonlinear system can result in large differences in a later state , e.g. a butterfly flapping its wings in Brazil can cause a tornado in Texas .   Small differences in initial conditions ( such as those due to rounding errors in numerical computation ) yield widely diverging outcomes for such dynamical systems -- a response popularly referred to as the butterfly effect - rendering long-term prediction of their behavior impossible in general . This happens even though these systems are deterministic , meaning that their future behavior is fully determined by their initial conditions , with no random elements involved . In other words , the deterministic nature of these systems does not make them predictable . This behavior is known as deterministic chaos , or simply chaos . The theory was summarized by Edward Lorenz as :   Chaotic behavior exists in many natural systems , such as weather and climate . It also occurs spontaneously in some systems with artificial components , such as road traffic . This behavior can be studied through analysis of a chaotic mathematical model , or through analytical techniques such as recurrence plots and Poincaré maps . Chaos theory has applications in several disciplines , including meteorology , sociology , physics , environmental science , computer science , engineering , economics , biology , ecology , and philosophy .  The theory formed the basis for such fields of study as complex dynamical systems , edge of chaos theory , self-assembly process .


Chemistry

Chemistry is a branch of physical science that studies the composition , structure , properties and change of matter . Chemistry includes topics such as the properties of individual atoms , how atoms form chemical bonds to create chemical compounds , the interactions of substances through intermolecular forces that give matter its general properties , and the interactions between substances through chemical reactions to form different substances .   Chemistry is sometimes called the central science because it bridges other natural sciences , including physics , geology and biology . For the differences between chemistry and physics see comparison of chemistry and physics .   The history of chemistry can be traced to alchemy , which had been practiced for several millennia in various parts of the world .


Chernobyl disaster

The Chernobyl disaster , also referred to as the Chernobyl accident , was a catastrophic nuclear accident . It occurred on 26 April 1986 in the No. 4 light water graphite moderated reactor at the Chernobyl Nuclear Power Plant near Pripyat , in what was then part of the Ukrainian Soviet Socialist Republic of the Soviet Union ( USSR ) .   During a late night safety test which simulated a station blackout power-failure and in which safety systems were deliberately turned off , a combination of inherent reactor design flaws , together with the reactor operators arranging the core in a manner contrary to the checklist for the test , eventually resulted in uncontrolled reaction conditions that flashed water into steam generating a destructive steam explosion and a subsequent open-air graphite fire.Although most reports on the Chernobyl accident refer to a number of graphite fires , it is highly unlikely that the graphite itself burned . According to the General Atomics website < http://gt-mhr.ga.com/safety.php > : `` It is often incorrectly assumed that the combustion behavior of graphite is similar to that of charcoal and coal . Numerous tests and calculations have shown that it is virtually impossible to burn high-purity , nuclear-grade graphites . '' On Chernobyl , the same source states : `` Graphite played little or no role in the progression or consequences of the accident . The red glow observed during the Chernobyl accident was the expected color of luminescence for graphite at 700 ° C and not a large-scale graphite fire , as some have incorrectly assumed . '' Similarly , nuclear physicist Yevgeny Velikhov , < http://news.bbc.co.uk/2/hi/europe/4918742.stm > noted some 2 weeks after the accident that `` Until now the possibility of a catastrophe really did exist : A great quantity of fuel and graphite of the reactor was in an incandescent state '' That is , all the nuclear-decay heat that was generated inside the uranium fuel ( heat which would normally be extracted by back-up coolant pumps , in an undamaged reactor ) was instead responsible for making the fuel itself and any graphite in contact with it , to glow red-hot . This is contrary to the oft cited interpretation , which is that the graphite was red-hot chiefly because it was chemically oxidizing with the air . This fire produced considerable updrafts for about 9 days , that lofted plumes of fission products into the atmosphere , with the estimated radioactive inventory that was released during this very hot fire phase , approximately equal in magnitude to the airborne fission products released in the initial destructive explosion . Practically all of this radioactive material would then go on to fall-out/precipitate onto much of the surface of the western USSR and Europe .   The Chernobyl accident dominates the Energy accidents sub-category , of most disastrous nuclear power plant accident in history , both in terms of cost and casualties . It is one of only two nuclear energy accidents classified as a level 7 event ( the maximum classification ) on the International Nuclear Event Scale , the other being the Fukushima Daiichi nuclear disaster in Japan in 2011 . The struggle to safeguard against scenarios which were , at many times falsely , perceived as having the potential for greater catastrophe and the later decontamination efforts of the surroundings , ultimately involved over 500,000 workers and cost an estimated 18 billion rubles . During the accident , blast effects caused 2 deaths within the facility and later 29 firemen and employees died in the days-to-months afterward from acute radiation syndrome , with the potential for long-term cancers still being investigated .   The remains of the No. 4 reactor building were enclosed in a large sarcophagus ( radiation shield ) by December 1986 , at a time when what was left of the reactor was entering the cold shut-down phase ; the enclosure was built quickly as occupational safety for the crews of the other undamaged reactors at the power station , with No. 3 continuing to produce electricity into 2000 .   The accident motivated safety upgrades on all remaining Soviet-designed reactors in the RBMK ( Chernobyl No. 4 ) family , of which eleven continued to power electric grids as of 2013 .


Cherry blossom

A cherry blossom ( or commonly known in Japan as sakura ) is the flower of any of several trees of genus Prunus , particularly the Japanese cherry , Prunus serrulata ( 桜 or 櫻 さくら ) .   Currently it is widely distributed , especially in the temperate zone of the Northern Hemisphere including Japan , China , Korea , West Siberia , Iran , Pakistan , India , Canada , and the United States . Along with the chrysanthemum , the cherry blossom is considered the national flower of Japan .   Many of the varieties that have been cultivated for ornamental use do not produce fruit . Edible cherries generally come from cultivars of the related species Prunus avium and Prunus cerasus . Cherry blossom are also closely related to other Prunus trees such as the almond , peach , plum and apricot , and more distantly to apples , pears and roses .


Chevron Corporation

Chevron Corporation is an American multinational energy corporation . One of the successor companies of Standard Oil , it is headquartered in San Ramon , California , and active in more than 180 countries . Chevron is engaged in every aspect of the oil , natural gas , and geothermal energy industries , including hydrocarbon exploration and production ; refining , marketing and transport ; chemicals manufacturing and sales ; and power generation . Chevron is one of the world 's largest oil companies ; , it ranked third in the Fortune 500 list of the top US closely held and public corporations and sixteenth on the Fortune Global 500 list of the top 500 corporations worldwide . It was also one of the Seven Sisters that dominated the global petroleum industry from the mid-1940s to the 1970s .   Chevron 's downstream operations manufacture and sell products such as fuels , lubricants , additives and petrochemicals . The company 's most significant areas of operations are the west coast of North America , the U.S. Gulf Coast , Southeast Asia , South Korea , Australia and South Africa . In 2010 , Chevron sold an average 3.1 million barrels per day ( 490 × 103 m3/d ) of refined products like gasoline , diesel and jet fuel .   Chevron 's alternative energy operations include geothermal , solar , wind power , biofuel , fuel cells , and hydrogen . In 2011 -- 2013 , the company planned to spend at least $ 2 billion on research and acquisition of renewable power ventures . Chevron has claimed to be the world 's largest producer of geothermal energy . In October 2011 , Chevron launched a 29-MW thermal solar-to-steam facility in the Coalinga Field to produce the steam for enhanced oil recovery . The project is the largest of its kind in the world .   Chevron is also one of the first two fuel brands to be Top Tier certified . The other is Tulsa , Oklahoma based QuikTrip .


Chicago

Chicago ( -LSB- ʃᵻˈkɑːɡoʊ -RSB- or -LSB- ʃᵻˈkɔːɡoʊ -RSB- ) , officially the City of Chicago , is the third-most populous city in the United States . With over 2.7 million residents , it is also the most populous city in both the state of Illinois and the Midwestern United States . It is the county seat of Cook County . The Chicago metropolitan area , often referred to as Chicagoland , has nearly 10 million people and is the third-largest in the U.S. Chicago has been called a global architecture capital . In terms of wealth and economy , Chicago is considered one of the most important business centers in the world .   Chicago was incorporated as a city in 1837 , near a portage between the Great Lakes and the Mississippi River watershed , and grew rapidly in the mid-nineteenth century . Positioned along Lake Michigan , the city is an international hub for finance , commerce , industry , technology , telecommunications , and transportation : O'Hare International Airport is the second-busiest airport in the world when measured by aircraft traffic ; the region also has the largest number of U.S. highways and rail road freight . In 2012 , Chicago was listed as an alpha global city by the Globalization and World Cities Research Network , and ranked seventh in the world in the 2016 Global Cities Index . Chicago has the third-largest gross metropolitan product in the United States -- about $ 640 billion according to 2015 estimates . The city has one of the world 's largest and most diversified economies with no single industry employing more than 14 % of the workforce .   In 2016 , Chicago hosted over 54 million domestic and international visitors , a new record making it one of the top visited cities in the nation . Landmarks in the city include Millennium Park , Navy Pier , the Magnificent Mile , Art Institute of Chicago , Museum Campus , the Willis ( Sears ) Tower , Museum of Science and Industry , and Lincoln Park Zoo . Chicago 's culture includes the visual arts , novels , film , theater , especially improvisational comedy , and music , particularly jazz , blues , soul , hip hop , gospel and house music . There are many colleges and universities in the Chicago area ; among these , Northwestern University , University of Chicago , and the University of Illinois at Chicago are classified as `` highest research '' doctoral universities . Additionally , Chicago has professional sports teams in each of the major professional leagues . The city has many nicknames , the best-known being the Windy City .


China

China , officially the People 's Republic of China ( PRC ) , is a unitary sovereign state in East Asia and the world 's most populous country , with a population of over 1.381 billion . Covering approximately 9.6 e6km2 , China is the world 's second-largest state by land area and third - or fourth-largest by total area . Governed by the Communist Party of China , it exercises jurisdiction over 22 provinces , five autonomous regions , four direct-controlled municipalities ( Beijing , Tianjin , Shanghai and Chongqing ) and the Special Administrative Regions Hong Kong and Macau , also claiming sovereignty over Taiwan . China is a great power and a major regional power within Asia , and has been characterized as a potential superpower .   China emerged as one of the world 's earliest civilizations in the fertile basin of the Yellow River in the North China Plain . For millennia , China 's political system was based on hereditary monarchies , or dynasties , beginning with the legendary Xia dynasty . Since 221 , when the Qin dynasty conquered the other largest six states to form the first unified Chinese empire , China has then expanded , fractured and re-unified numerous times in the following millennia . In 1912 , the Republic of China ( ROC ) replaced the last dynasty and ruled the Chinese mainland until 1949 , when it was defeated by the communist People 's Liberation Army in the Chinese Civil War . The Communist Party established the People 's Republic of China in Beijing on 1 October 1949 , while the ROC government relocated to Taiwan with its present de facto temporary capital in Taipei . Both the ROC and PRC continue to claim to be the legitimate government of all China , though the latter has more recognition in the world and controls more territory .   China has had the largest economy in the world for much of the last two thousand years , during which it has seen cycles of prosperity and decline . Since the introduction of economic reforms in 1978 , China has become one of the world 's fastest-growing major economies . , it is the world 's second-largest economy by nominal GDP and largest by purchasing power parity ( PPP ) . China is also the world 's largest exporter and second-largest importer of goods . China is a recognized nuclear weapons state and has the world 's largest standing army and second-largest defense budget . The PRC is a member of the United Nations , as it replaced the ROC as a permanent member of the U.N. Security Council in 1971 . China is also a member of numerous formal and informal multilateral organizations , including the WTO , APEC , BRICS , the Shanghai Cooperation Organization ( SCO ) , the BCIM and the G-20 .


Chinese remainder theorem

The Chinese remainder theorem is a theorem of number theory , which states that , if one knows the remainders of the division of an integer by several integers , then one can determine uniquely the remainder of the division of by the product of these integers , under the condition that the divisors are pairwise coprime .   This theorem has this name because it is a theorem about remainders and was first discovered in the 3rd century AD by the Chinese mathematician Sunzi in Sunzi Suanjing .   The Chinese remainder theorem is widely used for computing with large integers , as it allows replacing a computation for which one knows a bound on the size of the result by several similar computations on small integers .   The Chinese remainder theorem ( expressed in terms of congruences ) is true over every principal ideal domain . It has been generalized to any commutative ring , with a formulation involving ideals .


Chlorofluorocarbon

A chlorofluorocarbon ( CFC ) is an organic compound that contains only carbon , chlorine , and fluorine , produced as volatile derivative of methane , ethane , and propane . They are also commonly known by the DuPont brand name Freon . The most common representative is dichlorodifluoromethane ( R-12 or Freon-12 ) . Many CFCs have been widely used as refrigerants , propellants ( in aerosol applications ) , and solvents . Because CFCs contribute to ozone depletion in the upper atmosphere , the manufacture of such compounds has been phased out under the Montreal Protocol , and they are being replaced with other products such as hydrofluorocarbons ( HFCs ) ( e.g. , R-410A ) and R-134a .


Christopher Monckton, 3rd Viscount Monckton of Brenchley

Christopher Walter Monckton , 3rd Viscount Monckton of Brenchley ( born 14 February 1952 ) is a British public speaker and hereditary peer . He is known for his work as a journalist , Conservative political advisor , UKIP political candidate , and for his invention of the mathematical puzzle Eternity .   Early on in his public speaking career topics centred on his mathematical puzzle and conservative politics . In recent years his public speaking has garnered attention due to his advocacy of climate change denial and his views on the European Union and social policy .


City

A city is a large and permanent human settlement . Although there is no agreement on how a city is distinguished from a town in general English language meanings , many cities have special administrative , legal , or historical status based on local law .   Cities generally have complex systems for sanitation , utilities , land usage , housing , and transportation . The concentration of development greatly facilitates interaction between people and businesses , sometimes benefiting both parties in the process , but it also presents challenges to managing urban growth .   A big city or metropolis usually has associated suburbs and exurbs . Such cities are usually associated with metropolitan areas and urban areas , creating numerous business commuters traveling to urban centers for employment . Once a city expands far enough to reach another city , this region can be deemed a conurbation or megalopolis . Damascus is arguably the oldest city in the world . In terms of population , the largest city proper is Shanghai , while the fastest-growing is Dubai .


Clathrate gun hypothesis

The clathrate gun hypothesis is the popular name given to the hypothesis that increases in sea temperatures ( and/or drops in sea levels ) can trigger the sudden release of methane from methane clathrate compounds buried in seabeds and that are contained within seabed permafrost which , because methane itself is a powerful greenhouse gas , leads to further temperature rise and further methane clathrate destabilization -- in effect initiating a runaway process as irreversible , once started , as the firing of a gun .   In its original form , the hypothesis proposed that the `` clathrate gun '' could cause abrupt runaway warming on a timescale less than a human lifetime . It was thought to be responsible for warming events in and at the end of the last glacial maximum , however this is now thought to be unlikely .   However , there is stronger evidence that runaway methane clathrate breakdown may have caused drastic alteration of the ocean environment ( such as ocean acidification and ocean stratification ) and of the atmosphere of earth on a number of occasions in the past , over timescales of tens of thousands of years . These events include the Paleocene -- Eocene Thermal Maximum 56 million years ago , and most notably the Permian -- Triassic extinction event , when up to 96 % of all marine species became extinct , 252 million years ago .