If so, how can we prove it? Why should we care? Is Colorado’s Climate Changing?

Colorado Snow Pack Graph ftp://ftp.wcc.nrcs.usda.gov/data/snow/snow_course/table/history/colorado/05j42s.txt

Colorado Snowpack Source:

Type of Precipitation Rain vs Snow FIGURE 2-8. Trend in Snow vs. Rain in Winter (1949–2004) MORE SNOW LESS SNOW Fig Changes in the fraction of winter precipitation falling as snow vs. rain (1949–2004), after correcting for trends in precipitation amount. Blues indicates increasing fraction of snow; yellow decreasing fraction. Data are from NWS COOP stations. (from Knowles et. al. 2006, FIGURE 7)

Average Yearly Precipitation in Colorado Colorado Climate Report 2008

Average Yearly Temperatures in Colorado Colorado Climate Report 2008

Frequency of large forest wildfires vs. average temperatures during fire season (March-August) A. L. Westerling et al., Science 313, (2006)

Number of Days Over 100°F Darker colors represent higher number of days over 100 F

Peak River Flow Peak River Flow Days– South Platt River Basin

Arapaho Glacier, Boulder County, Colorado - comparison photos: 1898 (Photo J.R. Brackett): 1960 (Photo H. Waldrop) 2000 (Photo W.T. Pfeffer)

Rowe Glacier, Colorado - comparison photos Rowe Glacier, August, 25, 1916 (Photographer: W.T. Lee; NSIDC)NSIDC Rowe Glacier, September 18, 2004 (Photographer: Andy Leach; leachfam.com)leachfam.com

Temperature Changes and the Change in the Latitudinal Location of Bird Species

Pika Habitat

What is projected for the future in Colorado?

Future Projections -Temperature

Future projections - Temperature Observed and Projected Temperature Rise for the Southwest The average temperature in the Southwest has already increased roughly 1.5°F compared to a baseline period. By the end of the century, average annual temperature is projected to rise approximately 4°F to 10°F above the historical baseline, averaged over the Southwest region. The brackets on the thermometers represent the likely range of model projections, though lower or higher outcomes are possible.

Future Projections Number of Days Over 100°F The number of days in which the temperature exceeds 100°F by late this century, compared to the 1960s and 1970s, is projected to increase strongly across the United States. For example, parts of Texas that recently experienced about 10 to 20 days per year over 100°F are expected to experience more than 100 days per year in which the temperature exceeds 100°F by the end of the century under the higher emissions scenario.91

Future Projections for Rain from Nov to May Current Future Source: Kyoko Ikeda (Colorado Headwaters Project) What changes do you see?

Source: Kyoko Ikeda (Colorado Headwaters Project) What changes do you see? Future Projections for Snow from Nov to May Current Future

Future projections Projected Change in Spring Precipitation, Percentage change in March-April-May precipitation for compared to for a lower emissions scenario (left) and a higher emissions scenario (right). Confidence in the projected changes is highest in the hatched areas.

Future Projections - Runoff

Future Projections – Extreme Heat Number of Days Over 100°F The number of days in which the temperature exceeds 100°F by late this century, compared to the 1960s and 1970s, is projected to increase strongly across the United States. For example, parts of Texas that recently experienced about 10 to 20 days per year over 100°F are expected to experience more than 100 days per year in which the temperature exceeds 100°F by the end of the century under the higher emissions scenario.91

Future projections – snowpack

Spread of West Nile

Impacts of the changes on you 1. What’s the climate change, or climate change projection causing the impact? 2. How will it impact you? 3. What can you do to adapt or mitigate the impact?

Impacts of the changes resources