Satellites show Earth is greener. (Earth Science).Daily observations from space for nearly 2 decades indicate that our planet is getting greener. Satellites gathered data from 1982 to 1999, measuring the amount of chlorophyll on Earth. Analyses show that Earth's net primary production--a measure of how much foliage plants generate and, by inference, the amount of carbon dioxide carbon dioxide, chemical compound, CO2, a colorless, odorless, tasteless gas that is about one and one-half times as dense as air under ordinary conditions of temperature and pressure. they absorb--jumped about 6 percent over the period. On a global basis, land plants pulled 12.5 billion metric tons more carbon dioxide from the air in 1999 than they did 18 years earlier, says Ramakrishna R. Nemani of the University of Montana in Missoula. Although the concentration of carbon dioxide in Earth's atmosphere “Air” redirects here. For other uses, see Air (disambiguation). Earth's atmosphere is a layer of gases surrounding the planet Earth and retained by the Earth's gravity. It contains roughly (by molar content/volume) 78% nitrogen, 20.95% oxygen, 0.93% argon, 0. rose about 9 percent during that period, not all of the extra greenery stemmed from that gas' fertilizing effect. For example, large swaths of India received extra rainfall in the 1990s from that decade's strong monsoons, says Nemani. Also, decreased cloud cover over Amazonian rain forests enabled the trees there to slurp up 5 billion more metric tons of carbon dioxide in 1999 than they did in 1982. Net primary production in some regions did decline from 1982 to 1999. Cooling in Siberia led to a shorter growing season growing season, period during which plant growth takes place. In temperate climates the growing season is limited by seasonal changes in temperature and is defined as the period between the last killing frost of spring and the first killing frost of autumn, at which there, and a drop in precipitation in northern Mexico and the southwestern United States United States, officially United States of America, republic (2005 est. pop. 295,734,000), 3,539,227 sq mi (9,166,598 sq km), North America. The United States is the world's third largest country in population and the fourth largest country in area. stunted growth Stunted growth is a reduced growth rate in human development. It is a primary manifestation of malnutrition in early childhood, including malnutrition during fetal development brought on by the malnourished mother. of vegetation. Nemani and his colleagues report their analyses in the June 6 Science.--S.P. |
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