World leaders at last year’s global warming conference in Kyoto, Japan, learned that the counting of carbon dioxide will be essential in the new environmental economy.
Chief among the provisions of the the Kyoto Protocol is that countries will each receive annual allowances of emission credits that can be traded when one nation finds its carbon dioxide piggy bank running low. But the trouble with this eco-economy is quantifying the carbon emissions for each nation.
Fortunately, environmental scientists in the US have what they believe will be a good check on these balances in the form of a federally-funded project called AmeriFlux. The project is backed by a phalanx of federal agencies, including the Department of Energy, NASA, and the Department of Agriculture with the purpose of gathering data on carbon levels measured at various sites throughout the US, and eventually around the world. The idea is to use data culled from networks of sensors mounted in diverse environments, run complex equations, and crunch massive amounts of data to answer some basic questions: Where is Earth’s carbon dioxide going and why does it wind up in the places it does?
The answer, say the scientists, is not so straightforward. "For a long time, we thought it was the oceans that took up the carbon dioxide, but later we found it was on land and in the forests," explained David Hollinger, leader of the science team for AmeriFlux.
Such sleuthing is key in understanding –- and solving –- global warming, believed to be caused by the accumulation in Earth’s atmosphere of highly absorbent trace elements such as carbon dioxide. These greenhouse gases absorb energy from Earth, keeping it in the atmosphere to heat up the planet. In large amounts, global climates become unnaturally warm. Without any of the gases, the Earth would be much colder. The most critical of these gases to the Earth’s warming is carbon dioxide. Since the industrial revolution, the carbon dioxide concentration in the atmosphere has risen from 280 parts per million to 360 parts per million.
"Part of what we want to know is how its levels will change in the future –- where it will level off and where it will increase and decrease," said Ruth Reck, director of the National Institute for Global Environmental Change, one of the agencies backing AmeriFlux.
Seeds for AmeriFlux were sown in 1990 when a group of researchers combed through soil, vegetation, and air composition figures dating back to the 1600s in Harvard Forest. From this information, the researchers were able to see how changes to the area -- such as a conversion from forest to farm land and back to forest -- affected the overall environment. What they found was that this chemistry varied not only by land use, but also by climate -- changes in temperature, humidity, and precipitation also played a role, Reck noted.
Subsequent studies in forest areas in Maine and North Carolina showed scientists that latitude also made a difference –- forests at higher latitudes take up less carbon dioxide than those at lower latitudes. They also demonstrated the need to gather data from a variety of areas. The AmeriFlux network would fulfill this need.
Through monitoring stations peppering the nation from Alaska to Florida, sensors will read the wind to measure the amount of carbon dioxide in air going into a forested area and compare it with the levels present as air leaves the vegetation. From the difference of these equations, scientists can determine the amount of carbon dioxide that forest vegetation absorbs. And the data will be gathered constantly -– sensors are set to check the air five times per second or more.
Already, 24 stations are up and running in North America and organizers hope to join up with EuroFlux -- a similar network measuring carbon dioxide levels in Europe -- to give researchers more data to evaluate.
From this data, researchers hope to find such subtleties as whether a deciduous forest absorbs less carbon dioxide than a pine forest, or whether a young forest absorbs more than an old growth forest. They also hope to track the effects of grazing and other activities of animals and humans on the land to create a realistic model of how the Earth takes in carbon dioxide. Such figures can help scientists predict what limits there will be on the Earth’s ability to absorb carbon dioxide, for example.
At the very least, they’ll provide a good way of keeping nations that decide to adhere to the Kyoto Protocol honest, Reck said.
