Early melting of snow in the Arctic drives advancing springtime

Image credit: Jakob Assmann (2016)

New research indicates that spring snow melt, and to a lesser extent temperature, are key drivers of the timing of spring in the Arctic. 

These findings, from studies of plants from coastal sites around the Arctic, are important for understanding and documenting how the region is responding to climate change. The Arctic is warming more rapidly than anywhere else on the planet which may have huge consequences for the global system, and so understanding these changes is vital. 

Previously, data has shown differences in the timing of the start of spring across the Arctic over the last few decades. To understand the controls on this, researchers from universities in the UK, Denmark, Germany, Canada and the US, examined three perceived drivers of Arctic spring timing;temperature, snow melt date, and spring drop in sea ice extent. 

Using 22 years of monitoring data on 14 tundra plant species from four sites across the Arctic, the team showed that the timing of snow melt is key for vegetation leaf-out in spring and early-season

flowering. Changes to this may be causing mismatches in timing between herbivores and pollinators with plants, which can affect breeding success amongst other problems.  

“Vegetation change in the Arctic could potentially have considerable feedbacks on the global system” says Dr Jakob Assmann, lead author of the team’s most recent paper. For example, if vegetation is getting bigger, more carbon is absorbed which would help counteract the warming. However, Dr Assmann also points out that as snow cover is relatively thin in the Arctic, larger vegetation growing above it will provide a darker surface which will absorb more energy and lead to further warming. 

These results show that vegetation responses to rapid environmental change are more complex than a simple response to changing temperatures. Snow melt, and to a lesser extent temperature, are key factors controlling spring timing in some areas of the Arctic. Further research is needed to fully explore these changes and their impacts.

Jakob J. Assmann et al, Local snow melt and temperature—but not regional sea ice—explain variation in spring phenology in coastal Arctic tundra, Global Change Biology(2019). DOI: 10.1111/gcb.14639

This post was written by Lauren Shotter and edited by Ella Maria

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