Study relates influx of North American icebergs in Atlantic Ocean to increased methane production in tropical wetlands

A new study shows how huge influxes of fresh water into the North Atlantic Ocean from icebergs calving off North America during the last ice age had an unexpected effect – they increased the production of methane in the tropical wetlands. Usually increases in methane levels are linked to warming in the Northern Hemisphere, but scientists who are publishing their findings this week in the journal Science have identified rapid increases in methane during particularly cold intervals during the last ice age. These findings are important, researchers say, because they identify a critical piece of evidence for how the Earth responds to changes in climate.