U.S. Geological Survey Grassland Ecosystems http://www.usgs.gov/science/ science.php?term=499 See also: Agriculture industry; Desertification; Dust Bowl; Farmland; Overgrazing; Rangeland; Soil man- agement. Gravel. See Sand and gravel Greece Categories: Countries; government and resources Greece leads the world in the production of perlite and leads Europe in the production of bauxite and benton- ite. It also produces important quantities of magnesite and nickel. Greece exports about one-half of its ex- tracted minerals, but its substantial production of lig- nite is consumed internally. The country has few re- serves of petroleum, and it must import most of its oil and natural gas. The Country Greece is a small, mountainous country occupying the southern portion of the BalkanPeninsula in south- eastern Europe. It has a deeply indented coastline, and its more than 1,400 islands and islets make up about one-fifth of its area. Once very weak, Greece’s economy has expanded considerably since the mid- dle of the twentieth century, thanks in large part to economic aid from other countries, trade with the rest of Europe and the Middle East, and a steadily in- creasing influx of tourists. The rapid industrialization that the country has experienced since the 1970’s has encouraged a shift of population from rural areas to cities andhascreated seriousairandwaterpollution. In 2008, Greece had an estimated gross domestic product (GDP) in purchasing power parity of $343.6 billion, making it the thirty-third or thirty-fourth larg- est economy in the world and the eleventh largest in Europe. Greece joined the European Union (EU) in 1981, and in 2008, its per capita GDP was estimated to be thirty-two thousand dollars, which was fourteen hundred dollars below the average of the European Union. Manufacturing accounts for approximately one-fifth of its GDP, with service industries account- ing for most of the remainder. The value of the coun- try’s exports is only about one-third of the value of its imports. Bauxite, Alumina, and Aluminum Greece possesses Europe’s largest known deposits of bauxite, the mixture of minerals from which alumi- num is indirectly refined. Bauxite is regarded as the only naturally occurring material that the country ex- ploits at full capacity. Greece is believed to have re- serves of more than 100 million metric tons of baux- ite, with most of the deposits concentrated along the central mountain region of Parnassus-Giona-Helikon and on the country’s second largest island, Euboea, in the western AegeanSea. Both underground and open- pit mines are operated. Greece mined an estimated 2.16 million metric tons of bauxite in 2007, while its output of alumina, which representsanintermediatestageintheproduc- tion of aluminum, reached an estimated 780,000 met- ric tons the same year. The combined value of its ex- ports of bauxite, alumina, and related materials was $152 million in 2007. Greece is the largest supplier of bauxite in the European Union, although its increas- ing ability to produce its own aluminum has led to greater domestic consumption of bauxite and alu- mina. Bauxites Parnasse Mining Company pioneered the extraction of bauxite in Greece in 1933. However, only with the creation of Aluminum of Greece S.A. did the nation’s production of the metal itself begin. Alumi- num of Greece—a combine headed by the French- owned firm Pechiney and involving the American company Reynolds Metals aswellaspublicandprivate Greek funding—began operations in the 1960’s. The firm S&B Industrial Minerals S.A. supplied the com- pany with ore and went on to absorb Bauxites Par- nasse in 1996, while Aluminum of Greece merged with Mytilineos Holdings S.A. in 2007. As of 2009, most Greek bauxite production was under the direction of S&B and its subsidiary, Greek Helicon Bauxites S.A. Perlite According to published figures, Greece produces more perlite than any other nation on earth, turning out an estimated 1.65 million metric tons of the mate - rial in crude and screened forms in 2007. Perlite is a volcanic glass whose particles expand to many times 538 • Greece Global Resources Global Resources Greece • 539 Greece: Resources at a Glance Official name: Hellenic Republic Government: Parliamentary republic Capital city: Athens Area: 50,953 mi 2 ; 131,957 km 2 Population (2009 est.): 10,737,428 Language: Greek Monetary unit: euro (EUR) Economic summary: GDP composition by sector (2008 est.): agriculture, 3.7%; industry, 20.6%; services, 75.7% Natural resources: lignite, petroleum, iron ore, bauxite, lead, zinc, nickel, magnesite, huntite, marble, salt, hydropower potential, perlite, bentenite, kaolin, pumice Land use (2005): arable land, 20.45%; permanent crops, 8.59%; other, 70.96% Industries: tourism, food and tobacco processing, textiles, chemicals, metal products, mining, petroleum Agricultural products: wheat, corn, barley, sugar beets, olives, tomatoes, wine, tobacco, potatoes, beef, dairy products Exports (2008 est.): $29.14 billion Commodities exported: food and beverages, manufactured goods, petroleum products, chemicals, textiles Imports (2008 est.): $93.91 billion Commodities imported: machinery, transport equipment, fuels, chemicals Labor force (2008 est.): 4.96 million Labor force by occupation (2005 est.): agriculture, 12.4%; industry, 22.4%; services, 65.1% Energy resources: Electricity production (2007 est.): 59.33 billion kWh Electricity consumption (2006 est.): 55.98 billion kWh Electricity exports (2007 est.): 269 million kWh Electricity imports (2007 est.): 5.894 billion kWh Natural gas production (2007 est.): 24 million m 3 Natural gas consumption (2007 est.): 4.069 billion m 3 Natural gas exports (2007 est.): 0 m 3 Natural gas imports (2007 est.): 4.1 billion m 3 Natural gas proved reserves (Jan. 2008 est.): 1.982 billion m 3 Oil production (2007 est.): 4,265 bbl/day Oil imports (2005): 527,200 bbl/day Oil proved reserves (Jan. 2008 est.): 10 million bbl Source: Data from The World Factbook 2009. Washington, D.C.: Central Intelligence Agency, 2009. Notes: Data are the most recent tracked by the CIA. Values are given in U.S. dollars. Abbreviations: bbl/day = barrels per day; GDP = gross domestic product; km 2 = square kilometers; kWh = kilowatt-hours; m 3 = cubic meters; mi 2 = square miles. Athens Italy Bulgaria Turkey Greece Albania Macedonia Adriatic Sea Aegean Sea Black Sea Ionian Sea Mediterranean Sea their original sizes when heated and is used exten - sively in construction, horticulture, and industry. It has also proven useful in dispersing oil spills at sea. Perlite is found associated with sites of ancient volca- nic activity in the northeastern region of Thrace and on several islands in the southern Aegean Sea, includ- ing Melos, Kos, and Gyali—the last of which is also a major source of pumice. S&B is thecountry’s (and the world’s) largest miner of perlite. The company maintains several open-pit facilities on Melos, where it discovered deposits in 1954 and opened the continent’s largest facility in 1975. It operates another mine on Kos. The company exports mostof its production to Europe, North Amer- ica (where Armstrong Industries is a major customer), and Asia. Smaller producers include S&B subsidiary Otavi Mines Hellas S.A., with operations on Melos, and Aegean Perlites S.A., onGyali.Easyaccess to inex- pensive transportation by ship has helped these com- panies maintain an international price advantage. Thanks to aprojectsponsored by theEuropeanUnion, the expansion process necessary to perlite’s commer- cial utilization has also been greatly enhanced in re- cent years, resulting in higher quality. Bentonite and Kaolin Greece produces more bentonite than any other country in Europe and is second in world production only to the United States. Its total output (crude and processed) amounted to an estimated 952,500 metric tons in2007,nearly9percent of the world’stotal.Ben- tonite is a clay utilized in iron ore pelletizing, in foun- dering, as a binding agent in cement and adhesives, and in pet litter. The material is usually formed from the weathering of volcanic ash, and deposits are found on Melos and, toalesserextent,theislandofCimolus. It is mined from the surface in both locations. As is thecase with many of the country’s other min- erals, the bentonite market is dominated by S&B, which absorbed the second largest bentonite mining operation on Melos, Mykobar Mining Company S.A., in 1999. Mediterranean Bentonite S.A. also operates a small surface mine on Melos, but S&B accounts for about 85 percent of the country’s production. Most is exported to other countries of the European Union and to North America. Greece also possesses deposits of a second type of clay, kaolin, near Drama in the northeastern part of the country. The country produced an estimated 60,300 metric tons of kaolin in 2007, but because of its inferior nature, it was used only domestically in ce - ment and ceramic glazes. Nickel The common, industrially important element nickel is utilized primarily in the manufacture of stainless steel and other alloys. Greece mined an estimated 2.7 million metric tons of nickel ore in 2007, a level it had maintained more or less unchanged over the preced- ing several years. The country is thought to have nickel reserves of 250 million metric tons, with depos- its concentrated on the Aegean island of Euboea, on the mainland near Larimna opposite Euboea, and in northwestern Greece near the Albanian border. Deposits in the first two regions are “transported,” or secondary, meaning that they have been eroded and redeposited in new locations by natural forces—asitu- ation that makesfor easier extraction. The depositsof ore in the north evolved in place, and while they are more difficult to mine, they contain a higher content of nickel. Greece’s primary nickel producer (and one of the largest in the world) is the state-controlled General Mining and Metallurgical Company S.A. (LARCO), which was founded in 1963 and operates complexes of underground, open-pit, and closed-pit mines. Its oldest operation is at Agios Ioannisnear Larimna, the ore from which it began smelting in 1966. The com- pany’s mines in Euboea went into operation three years later. Today LARCO is one of the world’s largest producers of iron-nickel alloys and exports to a num- ber of steel manufacturers in Western Europe. Magnesite and Huntite Magnesite ore and its various processed forms— “dead burned” magnesia, calcined magnesite, and so on—have a variety of uses,includingthemanufacture of refractories (the linings of furnaces and the like) and synthetic rubber. The ore is also one of the sources oftheimportant industrialmetalmagnesium. High-grade deposits of magnesite are found in the Chalcidice peninsula in the northern part of Greece as well as in Euboea, but the latter deposits were not exploited after 1999. Greece producedmorethan3percent of the world supply of the material in 2007, an estimated 628,000 metric tons. Grecian Magnesite S.A. is the only active producer in Greece and the largest in the European Union. The company operates open-pit mines near Yerakina, where it also crushes and processes the 540 • Greece Global Resources magnesite into various application-specific grades, and exports virtually all its production to other Euro- pean Union countries. Deposits of the related mineral huntite are found in the Kozáni basin in the northern province ofMace- donia (not to be confused with the Republic of Mace- donia). It is used in papercoatingsandsealants and as a component of flame retardants. Greece is virtually the only commercial sourceforhuntiteandproduced an estimated 18,000 metric tons of the mineral in 2007, most of it for export. White Minerals S.A. and Microfine Hellas S.A. are the two producers. Pumice and Related Materials Greece is the second largest source of pumice in the world, producing an estimated 960,000 metric tons in 2007. The light, highly porous volcanic glass is used in horticulture and, particularly outside the United States, as aggregate in construction. Pumice is found on several Greek islands in the southern Aegean Sea. It was once mined on Thíra (also knownasSantorini), but today the only extraction taking place is on the is- land of Gyali, where pumice was deposited approxi- mately 200,000 years ago by a volcano on the nearby island of Nísiros. Lava Mining and Quarrying Com- pany, a subsidiary of Heracles General Cement, is Greece’s only pumice producer as well as the largest pumice exporter in the world. The company quarries the pumice without the use of explosives and loads ships bymeansofacomplexseries of conveyor belts. Lava Mining also quarries and distributes other in- dustrial materials associated with ancient volcanic ac- tivity. It extracts pozzolanic rock at Xylokeratia on Melos and gypsum at Altsi on the island of Crete, with the bulk of its production of both materials goinginto the domestic manufacture of cement. The micro- crystalline quartz it quarries on Melos is used in glass and ceramics. Lignite Lignite, or brown coal, is Greece’s only important nat- ural fuel source, and it accounts for about 60 percent of the country’s powergeneration. The country is the second largest producer of the material in the Euro- pean Union (afterGermany) and thefourth largest in the world. Greece is thought to possess reserves of nearly 7 billion metric tons of lignite in more than forty widely scattered basins, the largest of which is in Macedonia. Lignite is an inferior grade of coal, and the deposits in the Megalópolis region in the Pelo - ponnese Peninsula are of particularly poor quality. A large deposit in the Drama basin is also of poor quality and remains relatively unexploited. Greece produced an estimated 74 million metric tons of the material in 2007, most of it from open pits. Virtually all Greek lignite is mined by Public Power Corporation (PPC) S.A., which was founded in 1951 to exploit the reserves in Aliveri on the island of Euboea. A second company, Ptolemais Lignite Mines (LIPTOL), undertook a larger operation to extract the material from the Ptolemais deposit in the Pindus Mountains of northern Greece, eventually leading to one of the most substantial lignite mining and pro- cessing operations in the world. PPC acquired 90 per- cent of LIPTOL in 1959, and the two merged in 1975. PPC owns rights to about 60 percent of Greece’s known lignite reserves, using most of the material it- self. The company, which is state-controlled, gener- ates virtually all of Greece’s electrical power. Lignite’s use as an energy source poses serious en- vironmental problems, and Greece is under pressure from the European Unionto modernize its operation to reduce carbon emissions. Although it continues to rely on lignite, PPC also generates small amounts of hydroelectric power from dams on rivers in the Pindus Mountains. Other Resources Greece possesses modest deposits of gold, silver,chro- mite, lead, barite, and zinc. S&B has been active in identifying further deposits of gold, and Thracean Gold Mines S.A. (of which S&B is a part-owner) dis- covered a substantial deposit in Thrace in 1998. A small oil field in the northern Aegean Sea has been exploited since 1981. Discovered by the Ameri- can firm Oceanic and developed by the North Aegean Petroleum Company (NAPC)—a consortium headed by Denison Mines of Canada—the field reached a maximum production of30,000barrels per day (bpd) in 1989. However, production has fallen, while the country’s dependence on foreign petroleum has grown. In 2004, a larger field in the same area was identified west of the island of Thásos. Believed to contain approximately 227 million barrels, it is being developed by Kavala Oil S.A. and Energiaki S.A. and may reach production levels of 50,000 bpd. Marble has been quarried throughout Greece for millennia, and the country produced an estimated 150,000 cubic meters of the stone in various sizes of cuts in 2007. The major suppliers are Aghia Marina Global Resources Greece • 541 Marble Ltd., with quarries at Pallini, and Chris G. Karantanis & Sons Company at Corinth. Greece also produced about 60,000 metric tons of dolomite and 95,000 metric tons of flysch in 2007. Salt production yielded an estimated 195,000 metric tons the same year. Grove Koger Further Reading Arvanitidis, Nikos. “Northern Greece’s Industrial Minerals: ProductionandEnvironmental Technol- ogy Developments.” Journal of Geochemical Explora- tion 62, nos. 1-3 (1998): 217-227. Couloumbis, Theodore A., Theodore Kariotis, and Fotini Bellou, eds. Greece in the Twentieth Century. New York: Frank Cass, 2003. Curtis, Glenn E., ed. Greece: A Country Study. 4th ed. Washington, D.C.: Federal Research Division, Li- brary of Congress; Headquarters, Department of the Army, 1995. Grossou-Valta, M., and F. Chalkiopoulou. “Industrial Minerals and Sustainable Development in Greece.” In Mineral Resource Base of the Southern Caucasus and Systems for Its Management in the Twenty-first Century, edited by Alexander G. Tvalchrelidze and Georges Morizot. Boston: Kluwer Academic, 2002. Hatzilazaridou, Kiki. “A Review of Greek Industrial Minerals.” In Industrial Minerals and Extractive In- dustry Geology, edited by Peter W. Scott and Colin Malcolm Bristow.London:GeologicalSociety,2002. Kavouridis, Konstantinos. “LigniteIndustry in Greece Within a World Context: Mining, Energy Supply, and Environment.” Energy Policy 36, no. 4 (2008): 1257-1272. Kennedy, Bruce A. Surface Mining. Littleton, Colo.: Society for Mining, Metallurgy, and Exploration, 1990. Kogel, Jessica Elzea, et al. Industrial Minerals and Rocks: Commodities, Markets, and Uses. 7th ed. Littleton, Colo.: Society for Mining, Metallurgy, and Explora- tion, 2006. Konsolas, Nicholas, A. Papadaskalopoulos, and I. Plaskovitis. Regional Development in Greece. New York: Springer, 2002. Web Sites Greek Institute of Geology and Mineral Exploration http://www.igme.gr/enmain.htm Hellenic Republic Ministry of Development http://www.ypan.gr/index_uk_c_cms.htm See also: Aluminum; Marble; Perlite; Pumice. Green Revolution Categories: Environment, conservation, and resource management; historical events and movements Impending famine in the 1960’s in the underdevel- oped countries of Asia, Africa, and Latin America was averted by the Green Revolution, which was made pos- sible by the introduction of hybrid “miracle grains” of wheat and rice. Background From 1960 to 1965 a number of poor countries in the world could not produce enough food for their grow- ing populations. The Earth’s population had almost doubled to 3.7 billion people in fifty years, with more than 900 million people not getting adequate nour- ishment to lead productive lives. Famine had been avoided during the post-World War II period of his- tory only because production was high for American farmers and surplus grains were shipped overseas as food aid. In 1966 and 1967, the Indo-Pakistan subcontinent suffered two consecutive crop failures because of monsoons. The United States shipped one-fifth of its wheat reserves to India and sustained sixty million persons in India for a two-year period on American food shipments. It became obvious, as populations continued to grow, that the United States would not be able to continue to supply enough food to feed the world’s growing population adequately. In the mid- 1960’s, American policy began to change from giving poor countries direct food aid to educating and help- ing them to increase their own food production. The United States had, in the 1950’s, responded to an ailing agricultural economy in Mexico by sending scientists from the Rockefeller Foundation to develop a new wheat that yielded twice as much grain as tradi- tional varieties. The project was successful, and in 1962, the Rockefeller Foundation collaborated with the Ford Foundation to establish the International Rice Research Institute at Los Baños, in the Philip - 542 • Green Revolution Global Resources pines. Two strains of rice, PETA from Indone - sia and DGWG from China, were crossbred to produce a high-yield semidwarf variety of rice called IR-8. Both the new rice and new wheat were de- veloped to have short but strong and stiff stalks to support large heads of grain. Yields from the rice and wheat seeds were two to five times higher than traditional varieties as long as they were grown with large inputs of fertil- izer, water, and pesticides. Seeds were shipped to ailing countries. Asia expanded acreage planted in the new varieties from 81 hectares to 14 million hectares be- tween 1965 and 1969. Pakistan’swheatharvest increased 60 percent between 1967 and 1969. India’s production of wheat increased 50 per- cent, and the Philippines’ production of rice was so successful that it stopped importing rice and became an exporter. Positive Aspects The new seeds were dependent on irrigation by tube wells (closed cylindrical shafts driven into the ground) and electrical pumps. Irriga- tion methods were installed in poor countries. This new availability of water made it feasible for farmers to grow crops year-round. The dry season, with its abundant sunlight, had previ- ously been a time when crops could not be grown. With the advent of irrigation, the dry season became an especially productive grow- ing season. Poor countries in tropical and sub- tropical regions were able to grow two, three, and sometimes four crops a year. Approximately 90 per- cent of the increase ofthe world’s production of grain in the 1960’s, 70 percent in the 1970’s, and80 percent in the 1980’s was attributable to the Green Revolu- tion. The Green Revolution brought to politicians inde- veloping countries the realization that they could not depend permanently on food aid from other nations. Whereas leaders and politicians in these countries had previously concentrated on developing industrial projects, the extreme pressure of overpopulation on their limited food and land supplies caused them to address agricultural problems and give emphasis to programs to encourage production of food supplies. Countries that were affected by, and benefited from, the Green Revolution include India, Pakistan, Sri Lanka, the Philippines, Turkey, Burma (Myanmar), Malaysia, Indonesia, Vietnam, Kenya, the Ivory Coast, Tunisia, Morocco, Algeria, Libya, Brazil, and Para- guay. Drawbacks and Environmental Impact Large-scale pesticide application not only is costly but also can have an adverse effect on the environment. Only a small percentage of insecticides used on crops actually reach the target organism. The rest affects the environment by endangering groundwater, aquatic systems, pollinators, various soil-dwelling in- sects, microbes, birds, and other animals in the food chain. In addition, large water inputs are needed for proper irrigation of crops. Of the farmers who can af - ford to irrigate in poor countries, many do not do so properly, and thereby cause salinization, alkalization, Global Resources Green Revolution • 543 In this 1970 photograph, Norman Borlaug, considered the father of the Green Revolution, studies grains that he helped develop. (AP/Wide World Photos) and waterlogging of soils, rendering them useless for growing crops. Large-scale application of fertilizers is costly and reaches apointwhere further applications donotpro- duce the expected increase in yield and begin to cost far more than they are worth. Crop yields also de- crease because of increased soil erosion, loss of soil fertility, aquifer depletion, desertification, and pollu- tion of groundwater or surface waters. The Green Revolution exemplifies monoculture agriculture, the planting of large areas with a single type of seed. This use of monotypes can create multi- ple environmental problems. In many cases, the wide- spread use of genetically homogeneous seed caused old varieties with great genetic variability to be aban- doned. Crops consisting entirely of genetically homo- geneous rice and wheat are more vulnerable to dis- ease and insects, requiring inputs of agrochemicals which can be harmful to both the environment and human health. Planting vast hectares of monotypes has the potential to result in massive crop failure due to destructive fungi or chemical-resistant insects. Moreover,Green Revolution techniques rely heavily on fossil fuel to run machinery, to produce and apply inorganic fertilizers and pesticides, and to pump water for irrigation. Gasoline is costly and is often in short supply in many of the poor nations. Sociologically, the Green Revolution in poor countries favored wealthier farmers with the capital to pay the considerable costs of irrigation, seeds, fertilizers, pesticides, and fossil fuels. This fact has accentuated the financial gap be- tween the big and small farmers. Outlook The drawbacks of the Green Revolution have led farmers and scientists to seek safer and more diverse solutions to world food needs. Genetic engineers hope to be able to breed high-yield plant strains that have greater resistance to insects and disease, need less fertilizer, and are capable of making their own ni- trogen fertilizer so as not to deplete the soil of nutri- ents. Proponents of integrated pestmanagementcon- tinue to investigate combinations of crop rotation, time of planting, field sanitation, and the use of pred- ators and parasites as ways to control insects without the use of harmful chemicals. Regardless of develop- ments in food production and technology, however, in the longterm the mostimportant aspectofaddress - ing worldfoodneedsis to controlpopulationgrowth. Dion C. Stewart Further Reading Alauddin, Mohammad, and Clement Tisdell. The “Green Revolution” and Economic Development: The Process and Its Impact in Bangladesh. New York: St. Martin’s Press, 1991. Brown, Lester R. Seeds of Change: The Green Revolution and Development in the 1970’s. New York: Published for the Overseas Development Council by Praeger, 1970. Chiras, Daniel D., and John P. Reganold. Natural Re- source Conservation: Management for a Sustainable Fu- ture. 10th ed. Upper Saddle River, N.J.: Pearson Prentice Hall, 2009. Cotter, Joseph. Troubled Harvest: Agronomy and Revolu- tion in Mexico, 1880-2002. Westport, Conn.: Prae- ger, 2003. Miller, G. Tyler, Jr., and Scott Spoolman. Environmen- tal Science: Problems, Concepts, and Solutions. 12th ed. Belmont, Calif.: Brooks Cole, 2008. Perkins, John H. Geopolitics and the Green Revolution: Wheat, Genes, and the Cold War. New York: Oxford University Press, 1997. Shiva, Vandana. The Violence of the Green Revolution: Third World Agriculture, Ecology, and Politics. Lon- don: Zed Books, 1991. Singh, Himmat. Green Revolutions Reconsidered: The Ru- ral World of Contemporary Punjab. New York: Oxford University Press, 2001. Wu, Felicia, and William Butz. The Future of Genetically Modified Crops: Lessons from the Green Revolution. Santa Monica, Calif.: RAND Institute, 2004. See also: Fertilizers; Genetic diversity; Monoculture agriculture; Pesticides and pest control; Population growth; Rice; Wheat. Greenhouse gases and global climate change Categories: Environment, conservation, and resource management; geological processes and formations; pollution and waste disposal The greenhouse effect protects Earth and all life on the planet from succumbing to extremes of temperature at the same time that it threatens to overheat the planet as the concentration of greenhouse gases increases. 544 • Greenhouse gases and global climate change Global Resources Background The atmosphere is heated directly by carbon dioxide and water vapor absorbing heat or infrared energy from the Earth’s surface. Without this natural pro- cess, called the greenhouse effect, the average atmo- spheric temperature would be around 16° Celsius lower than it is now—too cold to support life. The ac- tivities of human beings have increased natural con- centrations of carbon dioxide and othergases,includ- ing chlorofluorocarbons (CFCs), fluorinated gases (HCFCs), methane (CH 4 ), nitrous oxide (N 2 O), and, to some extent, ozone (O 3 ), all now labeled, along with water vapor, as greenhouse gases. The average temperature has increased as well. This concurrent rise in temperature and greenhouse gas concentra- tion iscalledglobalclimate change or globalwarming. The concern is not with the “greenhouse effect” it- self, which in actuality is necessary for life on Earth. The cause for alarm is the intensification or enhance- ment of the greenhouse effect and the resulting changes in climate, weather patterns, and the oceans, and the effect of these on living organisms. Thus, the term global climate change is preferred over global warming because the effects are expected to extend to other aspects of climate beyond that of tempera- ture. The climate of the Earth is not stable; it haschanged from natural causes throughout Earth’s history, be- fore human beings existed, and it will continue to change. However, increased concentrations of green- Global Resources Greenhouse gases and global climate change • 545 Atmosphere Sun Earth The Greenhouse Effect The greenhouseeffect isaptly named: Someheat fromthe Sun isreflected back into space (smallsquiggled arrows), butsome becomestrapped by Earth’s atmosphere and re-radiates toward Earth (straight arrows), heating the planet just as heat is trapped inside a greenhouse. house gases from human activities, particularly indus - trialization, are now recognized as having a warming effect on the Earth’s atmosphere. The U.S. National Oceanic and Atmospheric Administration reported that measurements from land and oceans show that between 1850 and 2006 the global mean surface tem- perature increased between 0.56° and 0.92° Celsius, while from preindustrial timesto2006,theconcentra- tion of CO 2 grew from about 280 to about 380 parts per million (ppm). Much debate occurred in the late twentieth century about correlation or causality of temperature increase and the level of CO 2 . Most re- spected scientists ascribed the increase to human causes. However, resistance to this assessment existed, including from the federal government of the United States. In 2007, the Intergovernmental Panel on Cli- mate Change, created by the United Nations and the World Meteorological Organization, released a re- port based onsolid research and analysis of data byre- spected scientists from many different countries. It stated, at a high confidence level, with 90 percent as- surance statistically, that human activities were induc- ing climate change. Consequences—such as coastal flooding, loss of biodiversity, widespread drought, and extended heat waves—were more likely with con- tinued increases of greenhouse gases. As a result, calls came for peopleandgovernments to acttoreduce the chance of serious or even disastrous impacts. Greenhouse Gases and Resource Use Fossil fuels—petroleum, natural gas, and coal—have been identified as the main culprits in global climate change. The name fossil fuels reflects their origin from decomposed dead plants and animals over hun- dreds of millions of years. Industrialization has been literally fueled by the carbon in fossil fuels, providing heat energy for factories, electricity production, and transportation. Large amounts of carbon, which had been sitting in theEarth’scrust in the form of fossil fu- els, were burned and combined with oxygen, produc- ing CO 2 , whichintheatmosphere absorbed heat from the Earth’s surface, leading to documented increases in temperature. Methane, a major component of natural gas, is pro- duced naturally and by human activities, including livestock production and rice cultivation. Methane’s concentration grew from preindustrial levels of about 715 parts per billiontoabout1,774ppb in 2005, a gain of about 148 percent. Fluorinated gases, replacements for CFCs (contributors to ozone depletion), have grown in concentration. They have a higher green- house impact than CFCs. Nitrous oxide, produced naturally by plants, also reachestheatmosphere largely as a result of fertilizer use and fossil-fuel combustion. Its concentration increased about 18 percent from preindustrial levels of about 270 ppb to 319 ppb in 2005. Other actions contributing to increased green- house gases include removal of natural vegetation for urban and agricultural purposes. The elimination of green plants leads to reduced photosynthesis and therefore less carbon dioxide being removed and re- placed by oxygen. Furthermore, economic problems can result from deforestation and desertification as land loses its productivity. Climate Change and Resource Use Sea levels have risen around 12.2 to 22.3 centimeters from partial melting of the Greenland and Antarctic ice sheets, augmented by the physical expansion of 546 • Greenhouse gases and global climate change Global Resources U.S. Greenhouse Gas Emissions (millions of metric tons) 1990 2000 2002 2003 2004 2005 2006 Carbon dioxide 5,017.5 5,890.5 5,875.9 5,940.4 6,019.9 6,045.0 5,934.4 Methane gas 708.4 608.0 598.6 603.7 605.9 607.3 605.1 Nitrous oxide 333.7 341.9 332.5 331.7 358.3 368.0 378.9 High GWP gases 87.1 138.0 137.8 136.6 149.4 161.2 157.6 Source: U.S. Energy Information Administration, Emissions of Greenhouse Gases in the United States, 2006, 2006. Note: High GWP (global warming potential) gases are hydrofluorocarbons, perfluorcarbons, and sulfur hexafluoride. the warming ocean water. Coastal zones and small is - lands especially are in danger not only from flooding but also from effects of enhanced storms. Biodiversity of the oceans, including in the Great Barrier Reef, is threatened. In Europe, although the growing season is now warmer and crop yields and forest growth have increased, more intense heat waves and widespread flooding have caused health and safety problems. Melting of glaciers in theHimalayas andsnowpacksin the mountains of the western United States and Can- ada is likelyto cause floods andmaybe avalanches. Be- cause ice reflects sunlight, as Arctic ice melts, the rate of global warming may accelerate. Salinization and desertification are likely in currently productive agri- cultural lands in dry regions in South America. As the oceans have become warmer, levels of salinity and CO 2 have changed, probably altering ocean currents and their distribution of heat. The acidity of the oceans has changed as well, perhaps greatly disrupt- ing fisheries, coral reefs, and marine ecosystems as a whole. Possible Changes in Resource Use Calls and actions for reducing carbon emissions and lessening the output of other greenhouse gases have intensified around the world. Conservation is an im- portant option, but some people are concerned that limiting the economic activities that produce CO 2 will hurt the economy. Yet conservation can build its own industries, as indicated by the number of “green” products being introduced. Margaret F. Boorstein Further Reading Abrahmason, Dean Edwin, ed. The Challenge of Global Warming. Washington, D.C.: Island Press, 1989. Archer, David. Global Warming: Understanding the Fore- cast. Malden, Mass.: Blackwell, 2007. Firor, John. The Changing Atmosphere: A Global Chal- lenge. New Haven, Conn.: Yale University Press, 1990. Gore, Al. An Inconvenient Truth: The Planetary Emer- gency of Global Warming and What We Can Do About It. Emmaus, Pa.: Rodale Press, 2006. Gribbin, John. Hothouse Earth: The Greenhouse Effect and GAIA. New York: Grove Weidenfeld, 1990. Johansen, Bruce E. Global Warming 101. Westport, Conn.: Greenwood Press, 2008. Kraljic, Matthew A., ed. The Greenhouse Effect. New York: H. W. Wilson, 1992. Krupp, Fred, and Miriam Horn. Earth, the Sequel: The Race to Reinvent Energy and Stop Global Warming. New York: W. W. Norton, 2008. Metz, Beth, ed. Climate Change 2007: Mitigation of Cli- mate Change—Contribution of Working Group Three to the Fourth Assessment of the Intergovernmental Panel on Climate Change. New York: Cambridge University Press, 2007. Rowlands, Ian H. The Politics of Global Atmospheric Change. New York: St. Martin’s Press, 1995. Schneider,StephenH.GlobalWarming: Are We Entering the Greenhouse Century? San Francisco: Sierra Club Books, 1989. Solomon, Susan, ed. Climate Change 2007: The Physical Science Basis—Contribution of Working Group One to the Fourth Assessment Report of the Intergovernmental Panel on Climate Change. New York: Cambridge Uni- versity Press, 2007. Somerville, Richard C. J. The Forgiving Air: Understand- ing Environmental Change. 2d ed. Boston: American Meteorological Society, 2008. Svensson, Lisa. Combating Climate Change: A Transat- lantic Approach to Common Solutions. Washington, D.C.: Center for Transatlantic Relations, Johns Hopkins University, 2008. Tickell, Oliver. Kyoto2: How to Manage the Global Green- house. New York: Palgrave Macmillan, 2008. Web Sites Energy Information Administration, U.S. Department of Energy Greenhouse Gases, Climate Change, and Energy http://www.eia.doe.gov/bookshelf/brochures/ greenhouse/Chapter1.htm Environment Canada Greenhouse Gas Sources and Sinks http://www.ec.gc.ca/pdb/ghg/ghg_home_e.cfm National Oceanic and Atmospheric Administration Climate Program Office http://www.climate.noaa.gov U.S. Environmental Protection Agency Greenhouse Gas Emissions http://www.epa.gov/climatechange/emissions/ index.html#ggo See also: Agenda 21; American Chemistry Council; Climate Change and Sustainable Energy Act; Earth Global Resources Greenhouse gases and global climate change • 547 . tons of the mate - rial in crude and screened forms in 2007. Perlite is a volcanic glass whose particles expand to many times 538 • Greece Global Resources Global Resources Greece • 539 Greece: Resources. 22.3 centimeters from partial melting of the Greenland and Antarctic ice sheets, augmented by the physical expansion of 546 • Greenhouse gases and global climate change Global Resources U.S. Greenhouse. Emissions (millions of metric tons) 1990 2000 2002 2003 2004 2005 2006 Carbon dioxide 5,017.5 5,890.5 5,875.9 5,940.4 6,019.9 6,045.0 5,934.4 Methane gas 708.4 608 .0 598.6 603 .7 605 .9 607 .3 605 .1 Nitrous