Summer Q&A: this week is all about rain.

Does it rain in the Arctic?

YES IT DOES!

rain_in_the_arctic_Jef_Maion
A rainy day in the North. Photo by Jef Maion

Typically there is not a lot of rain, some areas are even referred to as polar deserts because they receive as little precipitation as the Sahara desert. Also most of the precipitation falls as snow during winter; it can even snow in summer. Rainfall is rather scarce but can happen when warm air is transported into the region. However, this might change drastically in the future due to climate change.

The impact of global climate change is most visible in the Arctic region. Temperature is rising more in the Arctic than in other parts of the world ( https://data.giss.nasa.gov/gistemp/maps/ ). As a consequence the hydrological cycle is strongly influenced and it is predicted that over the course of the 21st century an increase of 50-60% in precipitation is to be expected (Bintanja R, 2018). The lion share of the additional precipitation is estimated to fall as rain and not as snow, shifting the Arctic environment to a rain dominated ecosystem. The consequences of this shift are still unknown.

Richard Bintanja, climate researcher at the Royal Netherlands Meteorological Institute (KNMI) has shown with the use of 37 global climate models that most of the additional precipitation is caused by the retreat of sea-ice. Year after year the sea ice coverage in the Arctic is decreasing, repeatedly setting a new minimum (Stroeve et al. 2012). If sea-ice retreats, more open water is present. This will drastically increase the amount of evaporation. More evaporation leads to more clouds, what combined with a warmer climate gives rise to more precipitation in the form of rain. Moreover, the additional rain will feed a positive feedback system: the rain will melt even more sea-ice. It is not unlikely that in the future you will be able to go to the North Pole just by boat.

Increased loss of sea-ice is not the only consequence of more rain. With more rain and less snow, light isn’t reflected as much as before causing the soil to heat up which in turn can increase microbial activity in the soil. This can have severe consequences for soil nutrient cycling and impact globally important ecosystem functions such as storage and emission of greenhouse gasses (IPCC 2013). Not only microorganisms are impacted also e.g. polar bears and reindeer are impacted due to the effect on their hunting terrain and the species they prey upon.

How fast the climate will change remains uncertain however, that the changes are already happening stand for certain.

References:

http://sciencenordic.com/extreme-weather-arctic-causes-problems-people-and-wildlife

https://nsidc.org/cryosphere/arctic-meteorology/factors_affecting_climate_weather.html

https://doi.org/10.1029/2012GL052676

https://www.nature.com/articles/s41598-018-34450-3

https://www.ipcc.ch/site/assets/uploads/2018/03/WG1AR5_SummaryVolume_FINAL.pdf

Story by Lotte De Maeyer.