(ORDO NEWS) — Over the past 50 years, several new thermokarst lakes have formed in Alaska, whose surface is bubbling, releasing methane, a powerful greenhouse gas, into the atmosphere.
Since such lakes were formed as a result of the melting of permafrost, there may be even more of them in the near future.
The permafrost zone covers the polar regions of our planet: these are places where the earth’s temperature does not rise above zero degrees, and groundwater is present in the form of layers of ice.
In the process of global warming, the permafrost begins to melt, and with it the ice enclosed in the earth, which leads to the formation of sinkholes filled with melt water. This is how thermokarst lakes appear .
At first glance, such lakes are not much different from ordinary ones, except for the speed of formation: in just a few years, the ground level can fall by as much as three meters, and the spruce forest will be replaced by a water surface.
However, if you look closely, you can see a feature that worries scientists on the surface of the lake – slowly rising bubbles.
If you collect such bubbles in a gas trap, and then bring a match and open the valve, a bright flame will flare up, like on a gas burner.
The reason is simple: bubbles contain methane , the main component of natural gas and one of the most dangerous greenhouse gases.
When the permafrost below the surface of the lake melts, microbial activity increases there. Bacteria begin to break down dead plants and other organic matter trapped in the frozen ground for centuries, eventually releasing carbon dioxide and methane.
As a result, the bottom of such lakes resembles a sponge saturated with gas bubbles, and the surface of the water looks like a slowly boiling soup.
Naturally, in winter this process is slowed down due to the formation of ice, but ice saturated with gases turns out to be brittle, often breaks and forms vast polynyas, in which the process of methane release continues.
In some cases, the released gas even leads to the formation of ice domes over the surface of the lake, which break through in the spring and saturate the air with a huge amount of asphyxiating gas.
American scientists monitor the intensity of methane emission from existing lakes and the formation of new ones year-round through field research and satellite observations. This allows them to estimate greenhouse gas emissions in the region and predict their implications for future climate change.
Contact us: [email protected]