A new study by the University of Alaska Fairbanks shows that Tundra lakes resting atop permafrost regions might not be the global warming monsters they have traditionally been viewed as. In fact, the study reports, they have actually been cooling the Earth more than warming it.
Scientists have documented the carbon dioxide and methane emissions that come from the formation and drying of Tundra lakes, as well as methane bubbles appearing on the lakes’ surface. However, in the long run these lakes absorb more of these greenhouse gases than they emit.
The study looked at sites in northern Siberia where permafrost, which is frozen soil that covers nearly a quarter of the Northern Hemisphere, had thawed and then refrozen nearly 2 million years ago. Scientists found that there was more carbon accumulation than release at the study sites, meaning these lakes actually trapped more greenhouse gases than they let off.
While Tundra lakes do release greenhouse gases into the atmosphere as the permafrost beneath them thaws, this is only a short term problem. Scientists from the study say it is important to look at the big picture over a longer period of time, even thousands of years.
Plants in the lakes, like mosses, absorb atmospheric carbon over time, evening out the amount released. Sediment also refreezes organic material in a permafrost case when lakes are drained, which keeps such material from decaying and emitting gases. In fact, scientists even found many perfectly preserved plants at many of their study sites.
These lakes have proven to actually help reduce the effects of global warming overtime, but they can only do so if they remain viable and new lakes are formed. Unfortunately the current forecast predicts lakes drying up and disappearing as the permafrost beneath them continues to thaw.