Declining Snow and Ice Part I: Recent Trends

One of the things I'm doing while on sabbatical in Austria is revisiting our current knowledge of recent changes and projected future changes to Earth's cryosphere (the frozen water part of the Earth system including ice sheets, glaciers, and snow) and integratig this information into course materials and public talks.  Austria is a good place to do this because there is a great awareness and convern about changes to glaciers and snow here and winter tourism is a significant portion of their economy (as much as 6% of their GDP based on some estimates).  As a result, there's a great deal of useful information concerning changes to snow and its impacts on winter sports and tourism.  

But before taking a close look at Austria, let's take a step back and look at the big picture.  Globally averaged temperatures have increased about 1.4°C/2.5°F above pre-industrial levels and the past three calendar years (2023–2025) were the warmest on record.  In response, the "great melt" has begun, with declines in the mass of the Greenland Ice Sheet, Antarctic Ice Sheet, and glaciers.   

Since the late 1970s, the Greenland Ice Sheet has been losing mass, corresponding to about 18 mm (0.7") of sea-level rise.  

Source: https://climate.copernicus.eu/climate-indicators/ice-sheets 

Similarly, the Antarctic Ice Sheet has been losing mass, amounting in total to about 14 mm (0.55") of sea level rise. The graph below includes mass changes for three regions of the Antarctic Ice Sheet (East Antarctica, West Antarctica, and the Antarctic Penninsula, as well as the cumulative total for the entire continent.  

Source: https://climate.copernicus.eu/climate-indicators/ice-sheets 

Finally, glaciers have lost 9000 Gigatonnes of mass, the equivalent of another 27 mm (1 inch) of sea leel rise.  

Source: https://climate.copernicus.eu/climate-indicators/glaciers

These recent changes cannot be explained by a "rebound" from the Little Ice Age, a period of regional cooling, especially in the North Atlantic region.  Since the 1990s, the loss of land ice has been driven by human-caused global warming.  Additionally, although the contributions to sea level rise may seem small so far, they are an ominous harbinger of things to come. 

Zooming into Austria, temperatures are increasing faster than the global average and have increased 3.1°C/5.6°F since the pre-industrial period.  

Source: https://aar2.ccca.ac.at/technical-summary

The impacts on snow and ice here are very apparent, with the recently released Second Austrian Assessment Report on Climate Change (AAR2) concluding that "all glaciers in Austria have been losing mass and shrinking at an accelerating rate in recent years."  That's somewhat cautious wording.  Instead of shrinkage, the word disintegration is being used increasingly to describe the fracturing and collapsing of some glaciers.  

Austria has an extensive network of snow observations.  They reveal elevation-dependent trends in snow cover with the larget percentage declines in the lower elevations and smallest at higher elevations.  Below are the trends at Austrian stations from 1961–2021 showing statistically significant declines at most stations that increase with decreasing elevation below about 1750 meters.  

Source: Steenburgh (2023, based on data provided by Marc Olefs, Geosphere)

Most Austrian ski resorts have base elevations below 1750 meters and the vast majority below 1500 meters.  

In a coming post, we will look at projections for the future and expected impacts on snow and skiing.