Pan-Arctic Water-Carbon Cycles

Grant-in-Aid for Scientific Research (S) JSPS JAPAN

About Reserch

Thawing permafrost releases greenhouse gases such as methane enclosed in the frozen soil to the atmosphere, and it affects the global climate.
Thus, researches to understand the current situation and to predict future climate change are indispensable for humanity all over the world.

In order to predict the future of Arctic warming and estimate greenhouse gas budgets, it is necessary to conduct an integrated study on various factors such as Arctic sea ice extent, atmospheric water vapor flows, precipitation variation, changes in vegetation condition and river discharges in the surrounding continent of the Arctic.

We started this research project because there was no integrated research on the atmospheric- terrestrial water-carbon cycles in the region.

“Arctic is transformed”

report by SWIPA (Snow, Water, Ice and Permafrost in the Arctic)
Arctic Monitoring and Assessment Programme
Arctic Council

Arctic sea ice is shrinking every year on the Eurasian continent side (Figure 1).
In eastern Siberia, summer precipitation increased drastically in the mid-2000s, accelerating the thawing of permafrost, resulted in moistening the ground surface (Figure 2) and increased river discharge to the Arctic Ocean.

Figure 1
Sea ice concentration on 15 September 2007 in the Arctic Ocean and surrounding areas. The white line shows the sea area averaged in the 1980s, and the dark line shows the sea area averaged in the 2000s. Drawing using the Arctic Sea-ice Monitor HP
Figure 2
Expansion of Lake Thermokarst in the middle basin of the Lena River, eastern Siberia. (Every 5 years, taken in the same season and place. From Fedrov, Hiyama et al. 2014)

On the other hand, in Mongolia, summer precipitation decreased drastically during the same period. The drought lasted for many years, which has had a major impact on resource animals and the people who use them.

Thus, in northern Eurasia, including Siberia and Mongolia, the permafrost conditions in the region and the vegetation conditions such as taiga and tundra are changing due to large changes in the atmospheric-terrestrial water cycle that began with the shrinking Arctic sea ice extent.
In other words, it is a radical change in the Arctic Ocean-atmosphere-vegetation-permafrost-river system.

The uncertainties of climate change prediction can be improved by using spatiotemporal maps of water-covered area and vegetation condition in northern Eurasia which we produce in this study.

Finally, we estimate spatiotemporal maps on the fluxes of greenhouse gases over northern Eurasia and these will greatly contribute to the elucidation of the mechanism of Arctic warming.