Global Climate Change: Just the Facts

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Department Colorado State University Presented at Club 20 Fall

1 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

2 Fact 1: I I am a Climatologist

3 Fact 2: I I am NOT a Climate Change Scientist!

4 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

5 Summary for Policymakers If you want an abbreviated version, read: IPCC: Climate Change 2007: The Physical Basis (AR4) Click on: Summary for Policymakers

6 Fact 4: Those Those results represent the global majority (consensus) scientific perspective There There are also minority views

7 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.

8 Should we be concerned about Climate Change here in Colorado? Let s s first consider our climate history

9 Systematic weather data collection began in western Colorado in the 1890s Denver November 19-25, 1871

10 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

11 Colorado Weather Stations in 1890

12 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

13 The NWS stations remain the backbone network for longterm climate monitoring From Kelly Redmond, WRCC

14 What have we learned from nearly 120 years of continuous climate monitoring?

15 Winters are consistently colder than summers Average Monthly Temperature ( ) for Selected Station Grand Junction Delta Palisade Collbran Vail Climax Temperature (deg Fahrenheit) Jan Feb Mar Apr May Jun Jul Aug Sep Oct Nov Dec

16 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

17 Grand Junction Annual Mean Temperatures 60 Temperature (deg F) Grand Junction Annual Average Precipitation (inches) Precipitation (inches)

18 Precipitation varies by as much as 400% from a very dry year to a very wet year 18 Montrose Annual Precipitation Precipitation (inches)

19 Colorado Average Annual Precipitation

20 Colorado Statewide Water Year (Oct-Sep) Precipitation from Colorado Statewide Water Year Precipitation Year Precipitation (inches)

21 Drought Visits Our Area Regularly Photo by NRCS

22 Fraction of Colorado in Drought Based on 48 month SPI ( July 2007) Year Fraction (in percent)

23 Confidently detecting climatic trends is much more challenging and difficult than determining spatial patterns, seasonal cycles, or year-to to-year variations

24 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.

25 Denver All Stations Denver All Stations Denver (all 3 stations) Monthly Average Maximum and Minimum Temperatures Temperature (deg F) Denver City Tmax Denver WSFO Tmax DIA Tmax Denver City Tmin Denver WSFO Tmin DIA Tmin

26 Dillon Annual Precipitation Dillon Annual Precipitation Dillon Precipitation Precipitation (inches) Reservoir built, Station moved

27 Fort Collins Winter Temperatures Fort Collins Winter Temperatures Fort Collins Water Year Average Temperatures for Winter (Oct-Apr) Year Temperature (degree F)

28 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).

29 Colorado Cooperative Stations

30 Long-Term Analysis Stations

31 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

32 Grand Junction Winter Temperatures 60 Grand Junction, CO, Winter Average Temperatures 50 Temperature (deg F)

33 Montrose Winter Temperatures Montrose, CO, Winter Temperatures Temperature (deg F)

34 Grand Junction Spring Temperatures 80 Grand Junction, CO, Spring Average Temperatures 70 Temperature (deg F)

35 Montrose Spring Temperatures Montrose, CO, Spring Temperatures Temperature (deg F)

36 Grand Junction Summer Temperatures 100 Grand Junction, CO, Summer Average Temperatures 90 Temperature (deg F)

37 Montrose Summer Temperatures 100 Montrose, CO, Summer Temperatures 90 Temperature (deg F)

38 Grand Junction Fall Temperatures Grand Junction, CO, Fall Average Temperatures Temperature (deg F)

39 Montrose Fall Temperatures Montrose, CO, Fall Temperatures Temperature (deg F)

40 With even the best stations, there is uncertainty

41 Should Planners be concerned about Climate Change? Any Any trends so far are subtle, but that may not always be the case

42 Increases in greenhouse gases are real and large

43 When significant temperature trends begin, we will be able to detect them Colorado Statewide Summer Temperatures Colorado Statewide Average Summer (Jun-Aug) Temperature ( ) Temperature Average Temperature Temperature (deg F)

44 Detecting changes in precipitation will be much more difficult Colorado Statewide Water Year Precipitation Colorado Statewide Water Year (Oct-Sep) Precipitation from Precipitation (inches) Year

45 What should we do??

46 The Colorado Climate Center will continue to monitor Colorado s climate very closely

47 16 Grand Junction WSFO Grand Junction 2007 Water Year Year Year Averages Period of Record Average Water Year Accumulated Max Precip Min Precip Accumulated Precipitation (Inches) OCT NOV DEC JAN FEB MAR APR MAY JUN JUL AUG SEP

48 Park Reservoir Snotel (Grand Mesa)

49 We are also encouraging citizens across the State to help us measure local precipitation Photos by H. Reges

50 For information and to volunteer, visit the CoCoRaHS Web Site Support for this project provided by NSF Informal Science Education Program, NOAA Environmental Literacy Program and many local charter sponsors.

51 Colorado Climate Center Data and Power Point Presentations available for downloading

Colorado Weather and Climate Update

Colorado Weather and Climate Update Nolan J. Doesken State Climatologist Colorado Climate Center, Atmospheric Science Department, Colorado State University Presented to Colorado Livestock Association,