Decades earlier than expected, rain could outstrip snowfall in the Arctic

In August rain fell for the first time in recorded history on the highest point of the Greenland ice sheet

The Arctic is expected to see more rainfall than snow decades earlier than previously thought, new research has found.

The transition from snow to rain is being caused by rapid warming and sea-ice loss driven by the climate crisis.

Human activities, mainly the burning of fossil fuels, have caused the world to heat up around 1.1C over the past 200 years, and some regions are heating more quickly than others.

The Arctic, for example, is warming more than twice as fast as the global average. Arctic sea ice has been in decline since 1979, satellite observations revealed, with average sea ice extent at its lowest point since 1850.

The new study, from an international team led by the University of Manitoba, was published on Tuesday in the journal Nature Communications.

Lead researcher Michelle McCrystall, a postdoctoral fellow at Manitoba’s Centre for Earth Observation Science, said the changes will have “huge ramifications” including less snow cover, increased melting of permafrost, and “greater flooding events from increased river discharge”. All of it will have implications for wildlife and human populations, she noted.

In August, rain fell for the first time in recorded history on the highest point of the Greenland ice sheet.

“The fact that we’re getting rainfall on the summit of Greenland right now, and that we’re maybe going to get more rainfall into the future – it kind of staggers me,” Ms McCrystall said.

Arctic rainfall will vary depending on the season and region, researchers noted. The latest climate models revealed that rain will dominate autumn’s snowfall by 2050-2080 – and not decades later as older models had shown.

Less snowfall will impact what’s known as the “albedo feedback” – how reflective a surface is, and whether the sun’s rays bounce off or are absorbed.

Less brilliant-white snow cover means more light energy is absorbed by dark ocean waters and exposed earth, leading to increased carbon emissions, methane releases and thawing permafrost.

More rain than snow could devastate wild caribou, reindeer and muskoxen populations by freezing into icy layers and preventing them from foraging for food.

The team, made up of researchers from University College London, University of Colorado Boulder, University of Lapland and the University of Exeter, underlined the importance of curbing global temperature rise to the ambitious 1.5C set out by the 2015 Paris Agreement.

If we can remain below 1.5C, the team said, then the transition to more rain than snow may not occur in some regions of the Arctic.

The Intergovernmental Panel on Climate Change (IPCC), the world’s leading climate authority, also found that keeping to 1.5C rather than the Paris deal’s outer bounds of “well below” 2C, would mean less chance for summers without sea ice in the Arctic.

However the world is barreling towards a temperature rise in excess of 3C this century, the United Nations 2020 Emissions Gap Report found. On this trajectory, the transition to more rain will likely be unavoidable.

“The new models couldn’t be clearer that unless global warming is stopped, the future Arctic will be wetter; once-frozen seas will be open water, rain will replace snow,” Professor James Screen, of the Department of Mathematics and Global Systems Institute at the University of Exeter, said.