Scientists at the University of Washington (USA) came to the conclusion that early spring rains intensify the erosion of permafrost (cryolithozone), which is also located in Siberia, and contribute to the release of large amounts of methane, a greenhouse gas that enhances global warming. This was announced in a press release on Phys.org.
Researchers studied the processes of permafrost melting in the frozen swamps of the permafrost zone, located about 32 kilometers from the city of Fairbanks (Alaska), from 2014 to 2016. Experts monitored methane emissions in and around bogs, sedge growth rates and soil temperature changes at 16 different depths.
In 2016, scientists noticed that soil temperatures at the edge of the permafrost zone rose 20 days earlier than usual, and cumulative methane emissions increased by 30 percent over previous years. At the same time, the amount of precipitation was above average, as in 2014. The main difference between 2016 and 2014 was that the spring rains started earlier. Since the air is warmer than the earth in early spring, precipitation heats the ground. The soil quickly becomes oversaturated with moisture, the excess of which flows into frozen bogs and raises their temperature.
Warm swampy soil, in turn, accelerates the metabolism of microbes, which, due to a lack of oxygen, begin to oxidize available organic matter, releasing methane. The heating of the soil is confirmed by the fact that more sedges began to grow around the bogs. These plants also supply organic matter to microorganisms and facilitate the release of methane through the stems.
With an increase in the average temperature of the Earth due to anthropogenic emissions, spring precipitation in northern latitudes will fall earlier and faster. Wherever there is permafrost, including Siberia, the rate of thawing of frozen ground and the amount of methane released will increase. In addition, the destruction of the permafrost zone can lead to the destruction of buildings and infrastructure built on it.
