Dirty Little Secrets of the Greatest Snow on Earth and the Future of the Great Salt Lake

1. Dirty Little Secrets of the Greatest Snow on Earth and the Future of the Great Salt Lake Jim Steenburgh Department of Atmospheric SciencesUniversity of UtahJim.Steenburgh@utah.edu Contributors: Tom Painter, Trevor Alcott, John Horel, Thomas Reichler, Leigh Jones, Chris Landry, Jeff Deems, Annie Bryant, McKenzie Skiles, Ashley Powell, Jayne Belnap, Mark Miller, Jason Wolf, and many more...

2. Words of Wisdom Prediction is very difficult, especially about the future - Danish Physicist Niels Bohr And more so the Great Salt Lake - Jim Steenburgh

3. Global Temperature Change • Earth’s average surface temperature has increased 1.4°F since 1900 Source: Climatic Research Unit, University of East Anglia

4. Last decade 2°F warmer than 100 year average Warming trend larger than global average trend Frequency of “warm” years increasing Frequency of “cold” years decreasing Mother nature playing with loaded dice Utah Temperature Change 2008 1993

5. Utah Mountain Snowpack Courtesy: Randy Julander, NRCS • No clear linkage between global warming and long-term (75+ year) trends in Utah’s upper-elevation mountain snowpack • Recent fluctuations are within range of past variability • Graph uncorrected and does not include 2006-2010

6. Streamflow & Lake Level GSLB Hydrologic Observatory Prospectus • Decadal-scale variability continues to dominate lake levels • Lake levels currently low, but remain with range of past variability • Linkages between recent fluctuations and warming remain unclear

7. Key Points: Recent Climate Change • Earth is warming • Utah warming faster than global average, but with more variability • Temperature dice are “loaded” • Odds of warm seasons and years increasing • Odds of cold seasons and years decreasing • Year-to-year and decadal variability still dominate Utah snowpack and GSL level fluctuations • Unclear if snowpack and GSL dice are loaded yet Casinosupply.com

8. The Future • We are confident about warming but • How fast will it warm? • How sensitive is Utah snowfall & runoff to warming? • Will the storm tracks & lake-effect change? • What about variability/extremes? • More big years? More droughts? • What about climate feedbacks, surprises, and dirty little secrets? • What does this mean for the GSL?

9. Warren Washington, NCAR Want this: Reality Have this: 60x90 miles Utah Climate Prediction Challenges • Unique local climate – transition zone • Modeling precipitation very challenging • Complex terrain/lake effects

10. Wasatch Snowfall Sensitivity +1°C +2°C +3°C +4°C PC Base PC Base PC Base PC Base PC Top PC Top PC Top PC Top Alta Base Alta Base Alta Base Alta Base Mt. Baldy Mt. Baldy Mt. Baldy Mt. Baldy Percent of snow that will instead fall as rain with warming 10% 20% 30% 40% 50% Courtesy: John Horel and Leigh Jones, Univ. of Utah

11. Temperature Change by 2050 A1B, 1980-1999 vs. 2040-2059 Nov-Apr +2°C PC Base °C SLC 3°C 38°F PC Top 1980-1999 Alta Base St. George 8°C 46°F Mt. Baldy °C SLC 5°C 41°F 10% 20% 30% 40% 50% 2040-2059 St. George 10°C 50°F Courtesy Thomas Reichler Univ. of Utah

12. Range of Possibilities PC Base PC Base 6 Temperature Change °C +3°C PC Top PC Top 4 Alta Base Alta Base 2 Mt. Baldy Mt. Baldy 0 -2 2000 2020 2040 2060 2080 +1°C Northern Utah Winter (Nov-Apr) Temperature Change Relative to 1980-1999 2100 CO2 = 2.5x Pre-Industrial (~700 ppm)

13. Precipitation Changes You Are Here

14. Average Winter Precip Change A1B, 2040-2059 minus 1980-1999 Nov-Apr mm 5” more Absolute No Change % 12% Increase Relative Courtesy Thomas Reichler Univ. of Utah No Change

15. Dirty Climate Secrets & Thinking beyond CO2 Snow Optics Lab-Alta Site (SOLA) 30 April, 2009 Courtesy Tom Painter

16. Dust Plumes Sevier Lake Milford Flat Fire Courtesy Tom Painter

17. The Intermountain Haboob

18. Impact of Dust: A Perfect Storm Rabbit Ears Pass, Colorado • Dust decreases snow albedo (reflectivity) • Dust deposition comes generally in the spring (Neff et al, 2005) • solar irradiance is increasing • snowpack is warming • Dust generally accumulates in surface layers and is not entrained in melt - therefore, the surface continues to darken 43 ppmw 52 ppmw 306 ppmw 406 ppmw April, 2009 May, 2009 Courtesy Tom Painter

19. Changes in dust loading Post-disturbance ------------------------1850AD Pre-disturbance Neff et al (2008), Nature Geosciences

20. High Wind + Vulnerable Soils = Dust Storms Plants: rainfall timing, temperatures critical Rocks: cover low in many places Biological crusts: occur on all soils, but easily crushed Physical crusts: do not occur on sandy soils, easily crushed

22. Senator Beck Basin Study Area Courtesy Tom Painter

23. Concluding Thoughts • Trends expected to emerge during the 21st century include • Reduced snowfall and snowpack in low-to-mid elevation mountain areas • Upper elevation trends less clear • Earlier and less intense spring runoff • Increased demand for residential and agricultural irrigation • Lower average GSL levels and increased salinity • How quickly these trends dominate local climate variability remains an important area of research • Natural variability in the GSL system is very large and needs to be better understood • There is more to the story than GHG related warming • A comprehensive observing and modeling system is needed for the Great Salt Lake Basin

24. Snowfall Sensitivity: Snowbird Snowfall decrease (%) per Dec C at 9650 ft Courtesy: John Horel and Leigh Jones, Univ. of Utah

25. Concluding Thoughts • Future warming is already in the pipeline • Climate inertia • Socio-economic inertia • Efforts to reduce CO2 emissions will only have an impact after ~2040 • New modeling systems are needed to improve our understanding and prediction of the GSL basin • Need to consider decadal-scale prediction in addition to long-term trends • Must think beyond CO2 • Consider regional climate change as a multifaceted problem

26. The Trend? 10 Precipitation Change (in) 5 0 5 10 2000 2020 2040 2060 2080 Northern Utah Winter (Nov-Apr) Precipitation Change Relative to 1980-1999 2100 CO2 = 2.5x Pre-Industrial (~700 ppm) Slight Loading of Dice for “Wet” Winters But Is the Storm Track Right? No Lake-Effect Courtesy Thomas Reichler Univ. of Utah