Climate Change & Aspen: An Assessment of Impacts and Potential Responses

Adopted by the City of Aspen, Colorado in 2006, this report includes an assessment of possible climate change impacts to the city, provides an greenhouse gas emissions inventory for the city, sets emissions reductions goals, and facilitates coordination on climate action between city agencies and private entities. The assessment focuses on climate impacts on mountain snow, Aspen's ecology and ecosystem processes, socioeconomics of the ski industry, and the streamflow of the Roaring Fork River which provides municipal water supplies.  

Observed changes in Aspen documented in the assessment include a 6 percent decrease in precipitation and at 16 percent decrease in precipitation falling as snow; an increase in average temperatures of 3 degrees F, and a 20-day decrease in the number of frost-days. By 2030, the assessment projects a 3 to 4 degree F increase in average temperatures over 1990 levels, but the assessment notes uncertainty in projections for precipitation changes. By 2100, the assessment projects less snowfall, earlier spring run-off, and no skiable snow at the base by 2100.

In specific areas, the assessment includes the following key findings:

  • Ecology - plant communities will move to higher elevations, some plant and animal species are at risk of diminishing, some plant communities may disappear over time; the average fire size is projected to be approximately 50 percent larger than historic size; and climate change will increase the likelihood of pests and invasive plant species.  
  • Socioeconomic - it may be difficult to maintain a ski economy if global warming continues over the next century; changes in the hydrological cycle will affect municipal, agricultural, and recreational water users; and increased water temperatures and lower flows will have adverse effects on trout spawning and survival

The assessment relied upon climate models development by the National Center for Atmospheric Research and the Max Plank Institute.

This report was called for by a City Council resolution passed in March 2005.  

Publication Date: July 2006

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