Carbon dioxide is the gas most discussed in relation to manmade climate change. But there are other gases responsible for the greenhouse effect that climate scientists blame for global warming. Scientists say the presence of one of those gases, methane, can be expected to rise rapidly, should the planet continue to warm.
That's bad news, since methane, already the third most abundant greenhouse gas, has roughly 30 times the heat-trapping potency of CO2. Scientists have known for some time that methane is a byproduct of biological activity in the world's freshwater ecosystems. Microorganisms in freshwater lakes, rivers, ponds, and streams produce methane as they digest organic materials. But exactly how much methane these ecosystems were emitting, or would emit, remained a mystery.