Carbon dioxide: where does it all go?
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. : Where Does It All Go?
Scientists studying carbon dioxide have run into arithmetic problem. A research team reports that the world's oceans do not absorb nearly as much of this greenhouse gas greenhouse gas
Any of the atmospheric gases that contribute to the greenhouse effect.
greenhouse gas each year as previous work has suggested. Though they can't agree on whether to call it good or bad news, experts say it points out an unnerving un·nerve
tr.v. un·nerved, un·nerv·ing, un·nerves
1. To deprive of fortitude, strength, or firmness of purpose.
2. To make nervous or upset. ignorance about carbon dioxide.
"We've been overconfident o·ver·con·fi·dent
Excessively confident; presumptuous.
over·con for a long time about our knowledge of the carbon cycle. we've held on to the idea that the oceans were absorbing roughly 40 percent of the [carbon dioxide from] fossilfuel combustion. Now we really think that's wrong," says Pieter P. Tans, an atmospheric scientist with the National Oceanic and Atmospheric Administration Noun 1. National Oceanic and Atmospheric Administration - an agency in the Department of Commerce that maps the oceans and conserves their living resources; predicts changes to the earth's environment; provides weather reports and forecasts floods and hurricanes and in Boulder, Colo.
The burning of coal, oil and natural gas each year spews about 5.3 billion tons of carbon into the atmosphere in the form of carbon dioxide. Because oceans and land can absorb only a fraction of the gas, 3.3 billion tons a year go into the air, causing the carbon dioxide buildup that has concerned the world. Of all the "sinks" that pull carbon dioxide from the atmosphere, scientists assume that oceans -- particularly in the southern Hemisphere -- do most of the work.
But computer simulations and actual measurements dispute this assumption, says Tans, who worked with Inez Y. Fung from NASA's Goddard Institute for Space Studies The NASA Goddard Institute for Space Studies (GISS), at Columbia University in New York City, is a component laboratory of NASA's Goddard Space Flight Center Earth-Sun Exploration Division and a unit of The Earth Institute at Columbia University. in New York City New York City: see New York, city.
New York City
City (pop., 2000: 8,008,278), southeastern New York, at the mouth of the Hudson River. The largest city in the U.S. and with oceanographer Taro Takahashi of the Lamont-Doherty Geological Observatory in Palisades Palisades, cliffs along the west bank of the Hudson River, NE N.J. and SE N.Y., extending from N of Jersey City, N.J., to the vicinity of Piermont, N.Y., with a general altitude of from 350 ft to 550 ft (107–168 m). , N.Y. Fung described their work earlier this month in Toronto at a meeting of the American Institute of Biological Sciences The American Institute of Biological Sciences (AIBS) is a nonprofit scientific association dedicated to advancing biological research and education. Founded in 1947 as a part of the National Academy of Sciences, AIBS became an independent, member-governed organization in the 1950s. .
About 96 percent of the carbon dioxide from fossil-fuel combustion enters the atmosphere in the Northern Hemisphere. Although winds blow the gas around the world, measurements show that North Pole air contains 3 parts per million parts per million
mg/kg or ml/l; see ppm. (ppm) more carbon dioxide than South Pole air, Fung says. This number plays a key role in the new study.
Using an atmospheric general circulation model, Fung and her colleagues examined carbon dioxide's movement around the globe after its release during fossil-fuel combustion. By adding and subtracting various processes, they tested parts of the carbon cycle.
When they "turned off" the oceans and all other sinks for carbon dioxide, the computer atmosphere generated a north-south gradient of 4.4 ppm. With an ocean sink, working mostly in the south, the gradient increased--a result farther from the real value of 3 ppm. Fung says the simulations indicate the southern ocean cannot possibly account for most of the carbon dioxide absorbed worldwide. Only when the largest sink resides in the Northern Hemisphere does her model match real-world measurements.
Measurements show the northern oceans don't pull in much carbon dioxide, leading the researchers to suggest that land areas in the northern midlatitudes must absorb a staggering amount, between 1 billion and 2.5 billion tons of carbon a year.
If this is true, scientists face a grand mystery. Nobody knows what on land could store all that carbons, says ecologist Richard A. Houghton of the Woods Hole (Mass.) Research Center. Trees or soil might be doing the job, but Houghton and others say researchers should have noticed such conspicuous storage by now.
Lamont-doherty's Wallace S. Broecker Wallace S. Broecker ("Wally") (1931-) is the Newberry Professor in the Department of Earth and Environmental Sciences at Columbia University and a scientist at Columbia's Lamont-Doherty Earth Observatory. speculates that the finding may be good news. If soils currently absorb much of thecarbon dioxide from fossil-fuel combustion, he says, policymakers might consider using this natural process to reduce the greenhouse threat.
Takahashi sees it differently. "If what we're saying is true," he says, "it's more bleak than we used to think." He and others believe land areas cannot store as much carbon dioxide as the oceans, and may reach capacity in the foreseeable future. At that point, carbon dioxide would accumulate much more rapidly in the atmosphere, accelerating a greenhouse warming.