A crumbling permafrost bank on the shores of a lake reveals man-sized ice structures hidden in the frozen ground. The dark colour of the soil is due to the presence of organic material such as decomposed plant remains.
Photo: R\u00fana Magn\u00fasson<\/figcaption><\/figure>\nHow were the effects of precipitation in summer studied?<\/h3>\n
Scientists from the Plant Ecology and Nature Conservation chair group of WUR carried out an irrigation experiment on the Northeast Siberian tundra to investigate the impact of extreme summer precipitation on permafrost.<\/p>\n
PhD candidate R\u00fana Magn\u00fasson selected 20 monitoring sites and utilised sprinklers to give half the sites additional water. The experiment simulated the effects of an extremely wet summer. The sites were monitored for several years for permafrost thaw depth and other soil and vegetation characteristics.<\/p>\n
From this experiment, it was discovered that, on average the permafrost thawed 35% faster in the irrigated sites, leaving a larger amount of soil susceptible to the decomposition of soil carbon into greenhouse gas.<\/p>\n
Furthermore, an important finding was that the impact of an extremely wet summer lasted for several years; even two years after the sprinkler test, the permafrost under the irrigated sites was still thawing faster.<\/p>\n
Additional model analysis in cooperation with researchers from Stockholm University revealed that permafrost thaws particularly rapidly during periods of combined high rainfall and high air temperatures.<\/p>\n
\u201cWe were not surprised that the permafrost thawed to a greater depth during wet summers, but that the effect would be so extreme and last for several years was really unexpected,\u201d explained Magnusson.<\/p>\n
Can these negative effects be negated?<\/h3>\n
As rainfall is expected to increase and precipitation extremes will become more frequent in warming Arctic regions, these results hold negative connotations for the permafrost.<\/p>\n
\u201cIf we only take warmer temperatures into account, we will underestimate how much permafrost is thawing as a result of climate change, and how much extra CO2<\/sub> and methane is being released.<\/p>\n\u201cBut it is difficult to realistically represent the effect of such precipitation extremes on permafrost thaw and greenhouse gas emissions in climate models. This could lead us to underestimate future greenhouse gas emissions caused by permafrost thaw, and therefore our emissions targets to stay within the one-and-a-half or two degrees of global warming may turn out to be too optimistic,\u201d concluded Magnusson.<\/span><\/span><\/p>\nThe scientists hope that <\/span>f<\/span>uture <\/span>research <\/span>will<\/span> reveal the extent to which the sensitivity of permafrost to rain varies regionally, so that more reliable estimates of future permafrost thaw can be made.<\/span><\/p>\nTo keep up to date with our content,\u00a0subscribe for updates<\/a>\u00a0on our digital publication and newsletter.<\/p>\n","protected":false},"excerpt":{"rendered":"A research team from Wageningen University and Research (WUR) has discovered an increased acceleration in the rate that the Arctic permafrost is thawing. Why is the Arctic permafrost thawing? In the past 50 years, the Arctic region has been warming three times faster than the average rate of global warming. This has resulted in the […]<\/p>\n","protected":false},"author":21,"featured_media":19707,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_acf_changed":false,"_monsterinsights_skip_tracking":false,"_monsterinsights_sitenote_active":false,"_monsterinsights_sitenote_note":"","_monsterinsights_sitenote_category":0,"footnotes":""},"categories":[24433,785],"tags":[3478,3475,689,789],"acf":[],"yoast_head":"\n
Arctic permafrost thawing amid unexpected summer rainfall<\/title>\n\n\n\n\n\n\n\n\n\n\n\n\n\t\n\t\n\t\n\n\n\n\n\n\t\n\t\n\t\n