Global Climate Change: Just the Facts Nolan Doesken State Climatologist, Colorado Climate Center Atmospheric Science Department Colorado State University Presented at Club 20 Fall Meeting, Grand Junction, Colorado, September 8, 2007 Prepared by Odie Bliss
Fact 1: I I am a Climatologist
Fact 2: I I am NOT a Climate Change Scientist!
Fact 3: There is a lot of information out there about Climate Change If you want to get the latest scoop on the Global Scale,, read the Intergovernmental Panel on Climate Change (IPCC) 4 th Assessment http://www.ipcc.ch
Summary for Policymakers If you want an abbreviated version, read: IPCC: Climate Change 2007: The Physical Basis (AR4) http://www.ipcc.ch Click on: Summary for Policymakers
Fact 4: Those Those results represent the global majority (consensus) scientific perspective There There are also minority views
There There may be consensus regarding Global Climate Change Understanding local and regional climate change is much more difficult. That is the challenge at hand.
Should we be concerned about Climate Change here in Colorado? Let s s first consider our climate history
Systematic weather data collection began in western Colorado in the 1890s Denver November 19-25, 1871
In 1890 the USDA took over the responsibilities of climate monitoring on a national level, and the first civilian weather service was formed the U.S. Weather Bureau
Colorado Weather Stations in 1890
Since then, the U.S. Weather Bureau/National Weather Service has faithfully maintained an oft taken for granted network of weather stations in Colorado and across the country the Cooperative Observer Network Photo by Christopher Davey
The NWS stations remain the backbone network for longterm climate monitoring From Kelly Redmond, WRCC
What have we learned from nearly 120 years of continuous climate monitoring?
Winters are consistently colder than summers 90 80 Average Monthly Temperature (9171-2000) for Selected Station Grand Junction Delta Palisade Collbran Vail Climax Temperature (deg Fahrenheit) 70 60 50 40 30 20 10 0 Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec
Temperatures are far more stable than precipitation. In fact most other climatic elements (humidity, wind, sunshine and cloudiness, evaporation, etc.) are much more consistent from one year to the next than precipitation
Grand Junction Annual Mean Temperatures 60 Temperature (deg F) 58 56 54 52 50 48 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010 Grand Junction Annual Average Precipitation (inches) Precipitation (inches) 18 16 14 12 10 8 6 4 2 0 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
Precipitation varies by as much as 400% from a very dry year to a very wet year 18 Montrose Annual Precipitation Precipitation (inches) 16 14 12 10 8 6 4 2 0 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
Colorado Average Annual Precipitation
25 20 15 10 5 Colorado Statewide Water Year (Oct-Sep) Precipitation from 1896-2006 1995 1895 1900 1905 1910 1915 1920 1925 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 2000 2005 Colorado Statewide Water Year Precipitation Year Precipitation (inches)
Drought Visits Our Area Regularly Photo by NRCS
1.0 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0.0 Fraction of Colorado in Drought Based on 48 month SPI (1890 - July 2007) 1890 1892 1895 1897 1900 1902 1905 1910 1912 1915 1917 1920 1922 1925 1927 1930 1932 1935 1937 1940 1942 1945 1947 1950 1952 1955 1957 1960 1962 1965 1967 1970 1972 1975 1977 1907 1980 1982 1985 1987 1990 1992 1995 1997 2000 2002 2005 2007 Year Fraction (in percent)
Confidently detecting climatic trends is much more challenging and difficult than determining spatial patterns, seasonal cycles, or year-to to-year variations
We can find many frustrating limitations to our climate records: Changing instrumentation Aging weather observers Changing environments around our weather stations Changing weather station locations Automation, etc.
70 65 60 55 50 45 40 35 30 Denver All Stations Denver All Stations Denver (all 3 stations) Monthly Average Maximum and Minimum Temperatures Temperature (deg F) 1870 1875 1880 1885 1890 1895 1900 1905 1910 1915 1920 1925 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010 Denver City Tmax Denver WSFO Tmax DIA Tmax Denver City Tmin Denver WSFO Tmin DIA Tmin
30 25 20 15 10 5 0 Dillon Annual Precipitation Dillon Annual Precipitation Dillon Precipitation Precipitation (inches) 1995 1920 1925 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 2000 2005 Reservoir built, Station moved
45 43 41 39 37 35 33 31 29 27 25 Fort Collins Winter Temperatures Fort Collins Winter Temperatures Fort Collins Water Year Average Temperatures for Winter (Oct-Apr) 1890 1895 1900 1905 1910 1915 1920 1925 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Year Temperature (degree F)
Still, our climate records are more complete, consistent, and widespread than nearly all other forms of long-term environmental monitoring (i.e. we shouldn t t whine).
Colorado Cooperative Stations
Long-Term Analysis Stations
Recently, upward trends in seasonal temperatures have become noticeable in parts of Colorado That may be significant for water users/planners whether or not precipitation is changing
Grand Junction Winter Temperatures 60 Grand Junction, CO, Winter Average Temperatures 50 Temperature (deg F) 40 30 20 10 0 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
Montrose Winter Temperatures Montrose, CO, Winter Temperatures 60 50 Temperature (deg F) 40 30 20 10 0 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
Grand Junction Spring Temperatures 80 Grand Junction, CO, Spring Average Temperatures 70 Temperature (deg F) 60 50 40 30 20 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
Montrose Spring Temperatures Montrose, CO, Spring Temperatures 80 70 Temperature (deg F) 60 50 40 30 20 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
Grand Junction Summer Temperatures 100 Grand Junction, CO, Summer Average Temperatures 90 Temperature (deg F) 80 70 60 50 40 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
Montrose Summer Temperatures 100 Montrose, CO, Summer Temperatures 90 Temperature (deg F) 80 70 60 50 40 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
Grand Junction Fall Temperatures Grand Junction, CO, Fall Average Temperatures 80 70 Temperature (deg F) 60 50 40 30 20 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
Montrose Fall Temperatures Montrose, CO, Fall Temperatures 80 70 Temperature (deg F) 60 50 40 30 20 1880 1890 1900 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000 2010
With even the best stations, there is uncertainty
Should Planners be concerned about Climate Change? Any Any trends so far are subtle, but that may not always be the case
Increases in greenhouse gases are real and large
When significant temperature trends begin, we will be able to detect them 70 69 Colorado Statewide Summer Temperatures Colorado Statewide Average Summer (Jun-Aug) Temperature (1895-2006) Temperature Average Temperature 68 67 66 65 64 63 62 61 60 1895 1900 1905 1910 1915 1920 1925 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Temperature (deg F)
Detecting changes in precipitation will be much more difficult Colorado Statewide Water Year Precipitation Colorado Statewide Water Year (Oct-Sep) Precipitation from 1896-2006 25 20 15 10 5 1895 1900 1905 1910 1915 1920 1925 1930 1935 1940 1945 1950 1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 Precipitation (inches) Year
What should we do??
The Colorado Climate Center will continue to monitor Colorado s climate very closely
16 Grand Junction WSFO Grand Junction 2007 Water Year Year 2007 30 Year Averages-1971-2000 Period of Record Average - 1893-2002 2007 Water Year Accumulated Max Precip Min Precip Accumulated Precipitation (Inches) 14 12 10 8 6 4 2 0 OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP
Park Reservoir Snotel (Grand Mesa)
We are also encouraging citizens across the State to help us measure local precipitation Photos by H. Reges
For information and to volunteer, visit the CoCoRaHS Web Site http://www.cocorahs.org Support for this project provided by NSF Informal Science Education Program, NOAA Environmental Literacy Program and many local charter sponsors.
Colorado Climate Center Data and Power Point Presentations available for downloading http://ccc.atmos.colostate.edu