A study published recently in Global Change Biology brings bad news from the Arctic: spring is here – early. The research was funded by the UK Natural Environment Research Council and is a collaboration between researchers from the University of Edinburgh, and universities in Canada, the US, Denmark and Germany.
Better understanding the timing of activity in seasonal vegetation can give scientists a baseline to measure future changes – but it also allows them to see how the region is already being affected by climate change. For example, when certain species grow leaves and flowers is a clue which scientists can use to gauge rising temperatures and snow and sea ice melt.
Dr. Isla Myers-Smith, a co-author of the study from the University of Edinburgh's School of GeoSciences, commented: "In the extreme climate of the Arctic tundra, where summers are short, the melting of winter snows as well as warming temperatures are key drivers of the timing of spring. This will help us to understand how Arctic ecosystems are responding as the climate warms."
The team studied plants at different coastal sites around the Arctic tundra, focusing specifically on 14 species at four sites in Alaska, Canada and Greenland. They found that snow melt had a greater influence on the arrival of leaves and flowers than did temperatures.
“Spring temperatures and the day of spring drop in sea ice extent advanced at all sites (average 1°C per decade and 21 days per decade, respectively), but only those sites with advances in snow melt (average 5 days advance per decade) also had advancing phenology. Variation in spring plant phenology was best explained by snow melt date,” write the authors.
While spring phenology was quite variable across the team’s sites, they also found that when compared to twenty years ago, leaves and flowers are coming out as much as 20 days sooner now. “Within the same timeframe, spring temperatures warmed by 1 degree Celsius each decade on average, while loss of sea ice occurred around 20 days sooner across the different regions. Snow melt advanced by about 10 days over two decades,” explains Science Daily.
The scientists hope their research sheds light on the complexity of the relationships between temperatures, snow and sea ice melt, and Arctic ecosystems. With the Arctic warming more rapidly than any other region of the planet, it is imperative that we understand as much as possible about the factors at play in the region.