Arctic rainfall predicted to increase faster than expected

Kayaking in the Canadian Arctic. Photo credit -  Kerry Raymond

Nature Communications

The amount of rainfall in the Arctic may increase at a faster rate than previously thought, according to a modelling study published in Nature Communications. The research suggests that total rainfall will supersede snowfall in the Arctic decades earlier than previously thought, and could have various climatic, ecosystem and socio-economic impacts.

The Arctic is known to be warming faster than most other parts of the world, leading to substantial environmental changes in this region. Research suggests that there will be more rainfall than snowfall in the Arctic at some stage of the 21st century, but it is not yet clear when this shift will occur.

Michelle McCrystall and colleagues used the latest projections from the Coupled Model Intercomparison Project (CMIP6) to assess the changes in the Arctic water cycle by the year 2100. The authors found that precipitation, such as rainfall and snowfall, is projected to increase in all seasons. Rainfall is projected to become the dominant form of precipitation one to two decades earlier than previous models suggested, depending on the season and region, linked to increased warming and a faster decline of sea ice. For example, previous models projected the central Arctic to transition to a rainfall-dominated region in 2090, but it is now predicted to transition in 2060/2070. The authors suggest that a transition to a rainfall-dominated Arctic could occur at lower temperature thresholds than previous models projected, even at 1.5°C warming in some regions, such as Greenland.

The authors argue that more stringent climate mitigation policies are required, as a rainfall-dominant Arctic would have impacts on ice sheet melting, rivers and wild animal populations, and have important social-ecological, cultural and economic implications.