More Rain and Less Snow in the Arctic by 2100

Nature Communications, November 30

Updated climate models for the IPCC’s Sixth Assessment (AR6) reveal that precipitation in the Arctic is changing faster and on a larger scale than previously expected. Under a high-emissions scenario, rainfall will likely dominate seasonal precipitation patterns in the central Arctic by 2070, two decades earlier than anticipated by past models. Sea ice loss accelerates as global temperatures rise, which increases the amount of open water in the Arctic and allows more evaporation to take place. This evaporation forces moisture into the atmosphere and – in combination with an influx of humid air currents and elevated temperatures – leads to increased rainfall rather than snowfall in the Arctic. Rainfall is least dominant on a 1.5°C trajectory, but markedly more common already at 2°C of global warming. However, if we follow our current emissions trajectory toward 3°C of warming, rainfall is projected to dominate over most regions of the Arctic by the end of the century.

Rainfall-dominated precipitation reduces snow cover, decreases sea ice thickness, thaws permafrost, exacerbates flooding, and increases the likelihood of “rain-on-snow” events that can be devastating to local human communities as well as wild caribou and reindeer populations. It can also destabilize the Greenland Ice Sheet and accelerate its contribution to sea-level rise. Unless global emissions are curbed, we face the profound climatic, ecosystem and socio-economic impacts that are associated with a warming, wetter Arctic.

https://www.nature.com/articles/s41467-021-27031-y