for National Geographic News
In the fight against global warming, most innovations have been targeting the greenhouse gas "supervillain" carbon dioxide.
Meanwhile, several "henchmen" gases—some even more potent than CO2—have also been building up in Earth's atmosphere.
For now, none of these gases is as big a worry as CO2, due to its higher levels in the atmosphere. But if left unchecked, experts warn, these other compounds could create major new climate change battlefronts.
"The truth is we don't really have room for [these gases] to grow, in terms of the state that we are in with climate change," said Jay Gulledge, a senior scientist at the Pew Center on Global Climate Change in Arlington, Virginia.
"It is happening more rapidly than [it was] projected to happen."
Nitrous Oxide, aka "The Joker"
Most recently scientists warned that nitrous oxide, also known as laughing gas, already accounts for roughly 6 percent of the gases that fuel human-caused climate change.
The main culprit is animal manure, which releases N2O into the atmosphere, according to a new study by Eric Davidson, a senior scientist at the Woods Hole Research Center in Falmouth, Massachusetts.
Nitrous oxide emissions are first produced when fertilizer is added to the soil to grow animal feed. Animals then concentrate nitrogen inside their feces and urine, and soil microbes interact with the released waste to create N2O.
Burning fossil fuels, manufacturing nylon, and other industrial activities also emit the greenhouse gas, Davidson reported last week in the journal Nature Geoscience.
"If we just go on with business as usual with increasing food production, particularly increasing meat production, nitrous oxide will become an even bigger problem," Davidson said.
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