Manure management should therefore be part of future plans to combat climate change, the scientist concludes, and the Pew Center's Gulledge agreed.
One idea would be to set up a cap-and-trade scheme for farmers to encourage them to reduce their N2O emissions, Gulledge said. This would allow farmers who find ways to pollute less to sell their credits to, for example, carbon dioxide emitters.
"The caveat is we don't have a system for verifying those reductions," Gulledge said.
Methane, aka "Clayface"
In addition to laughing gas, scientists have their eyes on methane, the second largest contributor to climate change.
Methane accounts for about 15 percent of the warming that has occurred in the past century, Gulledge noted, and is 20 to 25 times more powerful than carbon dioxide.
"There is a potential for large amounts of methane to be emitted from natural systems as they warm," he noted.
For example, scientists are concerned that huge deposits of methane locked up in underwater permafrost around Earth's Poles could be released as oceans soak up heat and the frozen soil starts to melt.
And some evidence suggests methane is already being "belched" into the atmosphere as aboveground Arctic soils thaw.
"Right now we still control the composition of the atmosphere by our human activities," Gulledge said.
"If we pass a point where there's large scale thawing of these northern soils … we will no longer be able to control that."
Synthetic Refrigerants, aka "Mr. Freeze"
The other worrisome greenhouse goons are synthetic gases used as refrigerants, in heavy industry, and in consumer electronics.
Many are replacements for chlorofluorocarbons, or CFCs, which were phased out from sources such as refrigerators and air conditioners in the 1990s to prevent destruction of the Earth's ozone layer.
"The new replacements don't destroy ozone, but they are still greenhouse gases," Gulledge said.
These include hydrofluorocarbons, which come standard in today's air conditioners and refrigerators, and perfluorocarbons, which are used in the manufacture of semiconductors.
Sulfur hexafluoride is widely used in the electrical-utility industry to insulate high voltage equipment. The compound is 22,000 times more potent of a greenhouse gas than carbon dioxide over a hundred-year period.
Nitrogen trifluoride is used to make consumer electronics such as high-definition televisions, and it's about 17,000 times more potent than carbon dioxide.
"Anytime a building is built or a computer is made, these kinds of chemicals are being used," Gulledge said. "So they are increasing in the atmosphere."
For now, though, concentrations of synthetic gases are only about a millionth that of carbon dioxide and thus have little effect on global climate, Gulledge said.
And unlike carbon dioxide, these gases should be easy to reduce, he added.
"Our economy is based on fossil fuels, and that makes CO2 much harder to manage," Gulledge said.
"The other things [are] currently a very small part of the overall warming effect, and we can use our modern innovation technology process to figure out ways to phase them out."
|
SOURCES AND RELATED WEB SITES
|
