In August 2021, an unprecedented event occurred at the Greenland ice cap’s summit, where rain caused significant melting and retreat of the snowline, highlighting the growing frequency and impact of Arctic rain-on-snow events. This event prompted Joel Harper, a glaciologist at the University of Montana, to revisit earlier anomalies in his data from 2008, confirming it had rained significantly late in the season.
These findings underscore the increasing occurrence of Arctic rain-on-snow events, which are becoming more common due to rising Arctic temperatures, fundamentally altering the region’s climate and environmental conditions.
The consequences of Arctic rain-on-snow events are profound, affecting both the physical landscape and the biological ecosystems. Harper noted that such events alter the structure of the firn layer on ice caps, increasing susceptibility to future melting. This is critical as the Greenland ice sheet’s melting is a significant driver of global sea level rise. Moreover, increased rainfall leads to more severe flooding, landslides, avalanches, and challenges for Arctic wildlife, which already suffer from the climate-induced shifts in their habitats.
Historically, precipitation in the Arctic, a region too cold and dry for regular cloud formation, mostly fell as snow. However, with the Arctic warming at three times the global average rate, this trend is changing dramatically. Recent studies suggest a future with up to 60% more precipitation, predominantly rain rather than snow. This shift has implications for sea ice, glaciers, and Greenland’s ice cap, all of which are melting at unprecedented rates. The additional moisture contributes to faster permafrost thawing, altering water quality and increasing landslide and avalanche risks.
The Arctic rain-on-snow events not only pose environmental threats but also cultural and economic challenges for the Indigenous peoples who rely on the region’s natural resources. For example, rain-on-snow events have been linked to massive die-offs of reindeer and muskoxen, crucial for the subsistence of local communities. These events create ice barriers that prevent animals from accessing the vegetation needed for survival during the harsh winter months.
Furthermore, the impact on local wildlife and ecosystems can be seen in the increased mortality rates among caribou herds and other species vital to the Indigenous communities’ way of life. The rapid decline in caribou populations, for instance, jeopardizes the food security of Northern Indigenous people. This decline is attributed not only to changing climate conditions but also to Arctic rain-on-snow events that exacerbate the challenges these animals face from increased predation and habitat disruption.
In conclusion, the increase in Arctic rain-on-snow events represents a significant shift in the Arctic’s climatic system, with wide-reaching implications for its physical landscape, biodiversity, and the Indigenous communities dependent on these natural resources. As the Arctic continues to warm and these events become more frequent, understanding their impacts and developing strategies to mitigate these changes is crucial for preserving the Arctic environment and ensuring the sustainability of its inhabitants’ way of life.
www.eos.org/articles/rain-comes-to-the-arctic-with-a-cascade-of-troubling-changes