The Colorado Drought 2001-2003: A Growing Concern

1. The Colorado Drought 2001-2003: A Growing Concern Roger Pielke, Sr. and Nolan Doesken Colorado Climate Center Prepared by Tara Green and Odie Bliss http://climate.atmos.colostate.edu

3. 2002 Drought History in Colorado – A Brief Summary

4. Examples of Droughts • Snow does not fall in the mountains until late January • It is dry in April-July, but soaking rains occur in eastern Colorado in August • The weather of 2001-2002 repeats for the next five years • Colorado’s mountains have 90% of average snow for the next 20 years.

5. April 1 Snowpack

6. Drought Status on April 1, 2002 • Entire State Dry • Statewide Snowpack • 53% of Average • Bad, but not as bad as 1977 • Optimism for a wet spring – especially in Northern Colorado

7. But then came April • Very warm – especially in Mountains • Very Dry • Rapid Snowmelt • Little Runoff

8. May also failed us • Only one significant storm • High evaporation rates • Severe drought arrived !!

9. June 2002 • Some heavy rains on plains but little plant growth • Evaporation rates very high • Many grass fires • Even when some heavy rains did cometo eastern Colorado in early June, the ground was so hard, the vegetation on grazed lands was so short and the rains fell for such a short period of time, that little of the moisture soaked in – and vegetation remained parched.  Grass fires popped up all over eastern Colorado, keeping local fire fighters on their toes. • Extreme Drought in Mountains • Forest Fires exploded

10. By late June 2002 • Raging wildfires • Extreme low streamflows • Rapidly depleted reservoirs • Severe agricultural impacts • Wheat • Cattle • Irrigated crops in jeopardy • Intense heat • Urban water restrictions Hayman Fire Largest in Recent History

11. Widespread Drought • By late July 2002, Colorado near epicenter of extensive regional drought • Parts of nearly every state experiencing drought

12. August 2002 Pattern Changes • More extreme heat early • Another wildfire flare up • Severe storms late in August • Real relief in portions of the Eastern Plains • But most of Colorado still in extreme drought Steamboat Springs Fire Photo from Steamboat Springs Fire Department

13. The 1977 Drought

14. Total Precipitation AnalysisSeptember 2001 – August 2002 Ranking by Station

15. September 2002 Wet Weather at Last

16. Colorado Water Year 2002(Oct. 2001-Sept. 2002) Precipitation % of Average for the 1961-1990 Averages

17. Where are we now?

18. Through 1999

19. Through 1999

22. Colorado’s River Basin Snow Availability as of March 17, 2003 Source: http://www.wrcc.dri.edu/snotelanom/snotelbasin

23. Need to update?

27. 3 Month SPI

28. 12 Month SPI

29. 48 Month SPI

30. Colorado Needs • What would be the impact today of historical droughts? • What would be the impact today of paleo-droughts? • What if the 2001-2002 dry, warm weather reoccurred for 2002-2003? • How can we make Colorado more resilient to droughts? • What are the definitions of the multi-dimensional character of droughts.

31. Vulnerability Assessment • A vulnerability assessment of risk to climate and other environmental stress is, therefore, more appropriate as guides to Policy Makers, than trying to predict only a subset of possible future climate conditions.

32. Image by Jan Null, CCM, http://ggweather.com/winter0203.htm

33. Image by Jan Null, CCM, http://ggweather.com/winter0203.htm

34. Image by Jan Null, CCM, http://ggweather.com/winter0203.htm

35. Sept 1, 2001 to August 30,2002 was the driest for that period at most climate observing sites in Colorado. Over a several year time period, however, the current drought is a garden variety drought. It is not exceptional. Weather modification will not break a drought. At best, it slightly increases snowpack. The current drought is not a consequence of a warmer atmosphere. In fact, the Earth's atmosphere is no warmer today than it was in 1979. Models which have been used to predict climate a year or more in the future have demonstrated no skill in forecast ability. We should adopt vulnerability assessments as the preferred paradigm, rather than primarily focusing financial resources on prediction. In Conclusion

36. The Actual Global Heat Change in the Last 50 Years is Relatively Small Estimate of actual climate system heat change from the early 1950s-1995 is 0.3 Watts per meter squared (Pielke 2003)based on ocean heat storage changes (Levitus et al. 2000). Figure from Houghton et al. Eds., 2001: Summary for Policymakers: http://www.ipcc.ch

37. Effect of the Spatial Redistribution of Surface Heating (El Niño) • El Niño has a major effect on weather thousands of kilometers from the tropical Pacific Ocean (Shabbar et al. 1997). • The presence of warm SSTs permit thunderstorms to occur which otherwise would not have occurred. • These thunderstorms export vast amounts of heat, moisture, and kinetic energy to the middle and higher latitudes, which alter the ridge and trough patterns associated with the polar jet stream (Hou 1998). • El Niños have such a major effect on weather due to their large magnitude, long persistence, and spatial coherence (Wu and Newell 1998). • Tropical thunderstorms are referred to as “hot towers” and are the conduit to higher latitudes as part of the Hadley circulations (Riehl and Malkus 1958; Riehl and Simpson 1979). • Most thunderstorms occur over tropical and midlatitude land masses and in the warm season (Lyons 1999; Rosenfeld 2000). Therefore, the earth’s climate system must also be sensitive to land-use change in those regions where thunderstorms occur.

38. Global-Averaged Absolute Value Difference of Sensible and Latent Heat Fluxes Averaged for 12 Januaries: El Niño Teleconnection Average Latent Heat Flux January 6.1 Watts m-2 Average Sensible Heat Flux January 2.4 Watts m-2

39. Effect of the Spatial Redistribution of Surface Heating (Land-Use Change) From: Pielke Sr., R.A., G. Marland, R.A. Betts, T.N. Chase, J.L. Eastman, J.O. Niles, D. Niyogi, and S. Running, 2002: The influence of land-use change and landscape dynamics on the climate system: Relevance to climate change policy beyond the radiative effect of greenhouse gases. Phil. Trans. A. Special Theme Issue, 360, 1705-1719.

40. From: Pielke Sr., R.A., G. Marland, R.A. Betts, T.N. Chase, J.L. Eastman, J.O. Niles, D. Niyogi, and S. Running, 2002: The influence of land-use change and landscape dynamics on the climate system: Relevance to climate change policy beyond the radiative effect of greenhouse gases. Phil. Trans. A. Special Theme Issue, 360, 1705-1719.

41. From: Pielke Sr., R.A., G. Marland, R.A. Betts, T.N. Chase, J.L. Eastman, J.O. Niles, D. Niyogi, and S. Running, 2002: The influence of land-use change and landscape dynamics on the climate system: Relevance to climate change policy beyond the radiative effect of greenhouse gases. Phil. Trans. A. Special Theme Issue, 360, 1705-1719.

42. From: Pielke Sr., R.A., G. Marland, R.A. Betts, T.N. Chase, J.L. Eastman, J.O. Niles, D. Niyogi, and S. Running, 2002: The influence of land-use change and landscape dynamics on the climate system: Relevance to climate change policy beyond the radiative effect of greenhouse gases. Phil. Trans. A. Special Theme Issue, 360, 1705-1719.

43. Globally-Average Absolute Value of Sensible Heat Plus Latent Heat Only Where Land Use Occurred July January 1.08 Watts m-2 0.7 Watts m-2 Teleconnections Included July January 8.90 Watts m-2 9.47 Watts m-2 Redistribution of Heat Due to the Human Disturbance of the Earth’s Climate System Global redistribution of heat is on the same order as an El Niño.

44. The Actual Global Heat Change in the Last 50 Years is Relatively Small Estimate of actual climate system heat change from the early 1950s-1995 is 0.3 Watts per meter squared (Pielke 2003)based on ocean heat storage changes (Levitus et al. 2000). Figure from Houghton et al. Eds., 2001: Summary for Policymakers: http://www.ipcc.ch

45. Alteration in Surface Water Fluxes Associated With Land-Use Change Adapted from P. Kabat (personal communication, 1999). From Pielke Sr., R.A., 2001: Influence of the spatial distribution of vegetation and soils on the prediction of cumulus convective rainfall. Rev. Geophys., 39,151-177.

46. Alteration of Thermodynamic Profile Associated with Land-Use Change From Pielke Sr., R.A., 2001: Influence of the spatial distribution of vegetation and soils on the prediction of cumulus convective rainfall. Rev. Geophys., 39,151-177.

47. Effect of Land-Use Change on Deep Cumulonimbus Convection From Pielke Sr., R.A., 2001: Influence of the spatial distribution of vegetation and soils on the prediction of cumulus convective rainfall. Rev. Geophys., 39,151-177.

48. Smaller-Scale Spatial Variations in Landscape Change Also Affect the Water Cycle From Avissar and Liu (1996). Pielke Sr., R.A., 2001: Influence of the spatial distribution of vegetation and soils on the prediction of cumulus convective rainfall. Rev. Geophys., 39,151-177.

49. From Avissar and Liu (1996). Pielke Sr., R.A., 2001: Influence of the spatial distribution of vegetation and soils on the prediction of cumulus convective rainfall. Rev. Geophys., 39,151-177.

50. Summary • Landscape change and vegetation dynamics both result in a significant global redistribution of heat and water within the global climate system. • This redistribution of heat and water has already had an effect on the global climate system this is at least as large as the IPCC and National Assessment have attributed to the radiative effect of a doubling of carbon dioxide.