Estimating Potential Impacts of Climate Change on the Park City Ski Area Brian Lazar Stratus Consulting Inc. Mark Williams University of Colorado Institute of Arctic and Alpine Research

Objective: Evaluate Future Changes in Climate  Park City Ski Area  Years  2030  2075  2100  Climate  Air temperature  Precipitation

Climate Analysis Approach Emission scenarios - IPCC Climate response modeling - General circulation models (GCMs) - Regional climate models (RCMs) Scale to Park City - MAGICC/SCENGEN - Statistical downscaling - Dynamic downscaling Estimate effects on snow - SRM - Snow depth

Climate Change  “Climate change” refers broadly to any changes in climate (air temp, precip)  Here we focus on potential climate change caused by human emissions of greenhouse gases (GHG)  Carbon dioxide  Nitrous oxide  Methane

Recent Changes in Climate in the Park City Region

U.S. Air Temperatures Have Increased over the 20th Century  Warming in the US is concentrated in the mountain areas of the west.  The western US has warmed about 2°F in the last five years compared to the last 100 years. Source: Dr. Martin Hoerling, NOAA, Boulder, CO.

ALTA: Annual air temperatures ( )  Max air temperatures show no trend  Min temperatures are increasing about 0.8°F/decade

Summary of Annual Air Temperature Trends in the Park City Region 1.All weather stations show a warming trend for daily minimum temperatures (ranging from 0.05° to 1.6°F/decade) 2.No trend in daily maximum temperatures 3.Troubling: snowmaking depends on cold night- time air temperatures

Rising CO 2 Will Lead to Accelerated Rise in Air Temperature

Different Climate Scenarios  Three CO 2 warming scenarios  Business as usual (AIB)  Green scenario (BI)  Worst-case scenario (AIF1)  Three different years for each CO 2 scenario  2030: normal business projection  2070: threshold for large effects?  2100: long-term

5 x 5° Grid Boxes Near Park City  300 miles on a side  RCM box 20 miles on a side

Model vs. Observed Current (2000) Temperatures  Brian, can you add the observed line as an animation? Also, double the thickness of that line Remove shapes on lower right.

Projections of Climate Change

Annual Climate Changes in 2030: Business as Usual CO 2 Scenario  All GCMs show warming of 3-4°F  Little variability in temperature  Higher variability in precipitation  GCM average precipitation decreases by 7%

Summary of Projected Climate Change in 2030  Temperatures are projected to rise  GCMs project a 3° to 4°F rise  Little variability among models  Little variability among CO 2 scenarios  Adds confidence to interpretation  Warming most pronounced during the summer  Precipitation changes are uncertain  there is high variability across the GCMs

Potential Climate Changes in 2075: Business as Usual CO 2 Scenario  All GCMs show warming of 8° to 9.4°F  Little variability in temperature  Much higher variability in precipitation

Summary of Projected Climate Change in 2075  Temperatures are projected to rise  GCMs project a rise of 7.6° to 11.3°F depending on emission scenario  Warming most pronounced during the summer  Precipitation changes are uncertain  Although most models show a decrease (about 10 to 15% on average), there is high variability across the GCMs  Precipitation patterns show strong seasonality with slightly wetter winters and much drier summers

Potential Climate Changes in 2100: Business as Usual CO 2 Scenario  More warming: All GCMs show warming of 9.5° to 11.2°F  Continued variability in precipitation

Potential Climate Changes in 2100: Business as Usual, Worst Case and Best Case CO 2 Scenarios Annual averages B1:8.5°F A1B:10.4°F A1FI:15.2°F Warming most pronounced in summer  Bad CO 2 scenario almost twice as “hot” as best case CO 2 scenario

Summary of Projected Climate Change in 2100  Same as for 2075, except warmer  Different CO 2 scenarios have a large effect on air temperature by 2100:  These differences in future air temperatures have a large effect on snow at Park City in 2100

Climate Change Projections Summary  Today; Now: It’s getting hotter  Night temps 2-3  F warmer than in 1970  2030: warms another 3-4  F  Little difference among CO 2 scenarios  2070: large increases in air temp  CO 2 scenarios make a difference  2100: even larger increases in air temp  CO 2 scenarios make even larger difference  Precip: highly variable, not much confidence

Climate Change Bottom Line  It’s not gloom and doom  Continues to get gradually warmer  Really large change is 50 to 70 years in future  CO 2 scenarios have a large effect then  What the world does with CO 2 emissions today matters to your grand-children in 50 years  Caveat: These are deviations from average conditions  Science at this time is unable to deal with changes in the frequency of unusual years: droughts, large snow years, etc