Tuesday, June 8, 2010
Burps Maintained Warm Earth
National Geographic highlights a study that suggests when humans killed off mammoths and other Ice Age "megafauna" disappeared from the Americas ~13,000 years ago, their planet-warming burps left which created the Younger Dryas cooling period.
Dryas occurred ~1,000 years following human migration into the land, as did the extinction of 114 herbivorous species. The link between extinction and cooling is methane, a greenhouse gas 20x more powerful than C02 when it comes to global warming.
When digesting plant material, herbivores give off the gas - ~90% of which is burped. Records show the Dryas period had 2x-4x less methane than any other period in history.
The study suggests the cause is all the missing burps.