1. Climate Change: An Inter-disciplinary Approach to Problem Solving (AOSS 480 // NRE 480) Richard B. Rood Cell: 301-526-8572 2525 Space Research Building (North Campus) rbrood@umich.edu http://aoss.engin.umich.edu/people/rbrood Winter 2015 February 12, 2015

2. Class Information and News Ctools site: AOSS_SNRE_480_001_W15AOSS_SNRE_480_001_W15 –Record of course Rood’s Class MediaWiki SiteClass MediaWiki Site –http://climateknowledge.org/classes/index.php/Climate_Change:_The_Move_to_Actionhttp://climateknowledge.org/classes/index.php/Climate_Change:_The_Move_to_Action Next Tuesday, February 17 th, Guest Lecturer –Shelie Miller, Scenario Planning Tuesday, February 24 th, Dr. Frank Behrendt Seminar "The German Energiewende - Roadmap to Germany's Energy System 2050” Tuesday, February 24, 2015, 10:00 AM to 11:30 AM, Ross School of Business, Room R1210,

3. Resources and Recommended Reading Hegerl_Santer_Fingerprint_JClim_1996 Santer_Attribution_Fingerprint_Nature_19 96 Throughout the presentation

4. Outline: Class 11, Winter 2015 Attribution –Event attribution –Fingerprinting –Joint Attribution (end-to-end method) Rosenzweig et al., Nature, 2008 Projects East Coast Blizzard Discussion

5. Event Attribution Barriopedro et al., Russian Heat Wave, Science, 2011Barriopedro et al., Russian Heat Wave, Science, 2011 Dole et al., Russian Heat Wave, GRL, 2011 Rahmstorf, Increase of Extreme Events, PNAS, 2011Rahmstorf, Increase of Extreme Events, PNAS, 2011 Peterson_Stott_Attribution_2011_Extremes_ BAMS_2011 Shearer and Rood, Earthzine, 2011Earthzine, 2011 Hoerling, NOAA BrochureNOAA Brochure

6. Attribution

7. Signal to Noise From Leeds X-ray Imaging

8. Signal to Noise (perhaps more like climate) From social research methods.net

9. Signal to Noise (another example) From astronomy and astrophysics.org SignalNoise Signal / Noise Ratio

10. Some signal to noise issues We have many sources of variability –Sun, volcanoes, etc. –El Niño, La Niña, etc. –Ice ages, Little Ice Age, Warm Periods, etc. –Land use changes, natural carbon dioxide variability, etc. –How do we detect a trend in temperature and attribute it to human released carbon dioxide?

11. Attribution The physical climate and ecological observations in the previous are consistent with the planet is warming. How do we decide that this is consistent with human-induced warming?

12. Fingerprinting Barnett_Santer_Ocean_Heat_Attribution_ Science_2005 Santer_Attribution_Fingerprint_Nature_19 96 Hegerl_Santer_Fingerprint_JClim_1996

13. Natural mechanisms influence climate Changes in the Sun Changes in the amount of volcanic dust in the atmosphere Internal variability of the coupled atmosphere and ocean Natural mechanisms Thanks to Ben Santer for ContentBen Santer

14. Human factors also influence climate Non-natural mechanisms Changes in atmospheric concentrations of greenhouse gases Changes in aerosol particles from burning fossil fuels and biomass Changes in the reflectivity (albedo) of the Earth’s surface Smoke from fires in Guatemala and Mexico (May 14, 1998) Thanks to Ben Santer for Content!Ben Santer

15. Carbon dioxide is the most important greenhouse gas produced by human activities Atmospheric CO 2 has increased from a pre- industrial value of about 280 parts per million (ppm) to 379 390 400 ppm in 2005 2010 2014 The atmospheric concentration of CO 2 in 2005 2010 2014 exceeds by far the natural range (180 to 300 ppm) over the last 650,000 years Fossil fuel use is the primary source of the increased concentration of CO 2 since the pre- industrial period Recent changes in carbon dioxide are largely human-induced Source: IPCC AR4 (2007) Thanks to Ben Santer for ContentBen Santer

16. 1.“Basic physics” evidence –Physical understanding of the climate system and the heat-trapping properties of greenhouse gases 2.Circumstantial evidence –Qualitative agreement between observed climate changes and model predictions of human-caused climate changes (warming of oceans, land surface, and troposphere, stratospheric cooling, water vapor increases, etc.) 3.Paleoclimate evidence –Temperature reconstructions enable us to place the warming of the 20th century in a longer-term context 4.Fingerprint evidence –Rigorous statistical comparisons between modeled and observed patterns of climate change Multiple lines of evidence on which “discernible human influence” conclusions are based Thanks to Ben Santer for ContentBen Santer

17. Models can perform the “control experiment” that we can’t do in the real world Meehl et al., J. Climate (2004) Average surface temperature change (°C)

18. Strategy: Search for a computer model-predicted pattern of climate change (the “fingerprint”) in observed climate records Assumption:Each factor that influences climate has a different characteristic signature in climate records Method:Standard signal processing techniques Advantage:Fingerprinting allows researchers to make rigorous tests of competing hypotheses regarding the causes of recent climate change What is “climate fingerprinting”? Thanks to Ben Santer for ContentBen Santer

19. IPCC Temperature Observations Note: It gets smoother away from the surface.

20. Different factors that influence climate have different “fingerprints” 1. Solar 3. Well-mixed greenhouse gases 5. Sulfate aerosol particles 2. Volcanoes 4. Ozone 6. 1 st five factors combined Height (km) Pressure (hPa) °C/century Santer et al., CCSP, 2007

21. “Fingerprinting” with temperature changes in Earth’s atmosphere Model Changes: CO 2 + Sulfate Aerosols + Stratospheric Ozone Height (km) Pressure (hPa) Observed Changes Temperature changes in o C Santer et al., Nature (1996)

22. Initial work by Syd Levitus and colleagues showed an increase in the heat content of the oceans over the second half of the 20 th century (Levitus et al., 2001, Science) Subsequent research by Tim Barnett and colleagues identified a human fingerprint in the observed ocean heat content changes (Barnett et al., 2001, Science) Searching for fingerprints of human activities in the world’s oceans Thanks to Ben Santer for ContentBen Santer

23. “Fingerprinting” in the ocean: Warming of the North Atlantic over 1955-99 Barnett et al., Science (2005) Thanks to Ben Santer for ContentBen Santer

24. “Fingerprinting” in the ocean: Warming of the world’s oceans over 1955-99 Barnett et al., Science (2005) Thanks to Ben Santer for ContentBen Santer

25. Fingerprint detection explained pictorially…. Time-varying observed patternsTime-varying control run patterns t=1 t=2 t=3 t=4 t=n t=1 t=2 t=3 t=4 t=n Projection onto model fingerprint Signal and noise time series Signal-to-noise ratios Projection onto model fingerprint Model fingerprint Thanks to Ben Santer for ContentBen Santer

26. Human-caused fingerprints have been identified in many different aspects of the climate system Tropospheric temperatures Tropopause height Stratospheric temperaturesSurface specific humidity Ocean temperatures Zonal-mean rainfall Near-surface temperature Sea-level pressure Water vapor over oceans Continental runoff Atmospheric temperature Thanks to Ben Santer for ContentBen Santer

27. Continental warming likely shows a significant anthropogenic contribution over the past 50 years Key results of IPCC AR4: We are now able to identify human influences on climate at continental scales Thanks to Ben Santer for ContentBen Santer

28. Joint Attribution Rosenzweig et al., Nature, 2008

29. Summary from Rosenzweig et al., Nature, 2008Rosenzweig et al., Nature, 2008 shrinking glaciers in every continent melting permafrost shifts in the spring peak of river discharge associated with earlier snowmelt lake and river warming with effects on thermal stratification, chemistry and freshwater organisms increases in coastal erosion shifts in spring events (for example, leaf unfolding, blooming date, migration and time of reproduction), species distributions and community structure demonstrated changes in marine- ecosystem functioning and productivity, including shifts from cold-adapted to warm adapted communities, phenological changes and alterations in species interactions

30. Joint attribution What would you do to evaluate the theory and predictions of global warming? –Surface of planet will warm –Sea level will rise –Weather will change Think about Measurements Feedbacks Correlative behavior Impacts Joint Attribution Documented statistical analysis Process-level understanding

31. Joint attribution Joint Attribution –Documented statistical analysis –Process-level understanding Look to see for biological systems –Unlikely due entirely to natural variability –Consistent with estimated responses of physical or biological variables –Non consistent with alternative, plausible explanations That are in regions where physical variables, esp. temperature, can also be attributed to climate change Consist with behavior of models run with and without carbon dioxide increase

32. Global distribution of changes sensitive to temperature IPCC Technical Summary WG2

33. Summary: Class 11, Winter 2015 Attribution Event attribution

34. Summary: Class 11, Winter 2015 Fingerprinting Joint Attribution (end-to-end method) Rosenzweig et al., Nature, 2008

35. Outline: Class 11, Winter 2015 Attribution –Fingerprinting –Joint Attribution (end-to-end method) Rosenzweig et al., Nature, 2008 –Event attribution Projects East Coast Blizzard Discussion