1. Human fingerprints on our changing climate Neil Leary Changing Planet Study Group June 28 – July 1, 2011 Cooling the Liberal Arts Curriculum A NASA-GCCE Funded Project

2. Predictions from Earth sciences Emissions of CO2 and other GHGs from human activities will increase their concentrations in the atmosphere – Ratio of C12/C13 in atmosphere Global avg surface air temperatures will rise Time pattern of warming would correlate w/ timing of GHG concentration changes – – adjusting for changes in human & volcanic aerosols, changes in solar output – More warming in winter than summer – More warming at night than day Spatial pattern of warming – Widespread; expect warming to dominate on all continents – Greater warming over land than oceans – Greater warming at high northern latitudes Warming in troposphere, cooling in stratosphere Warming oceans

4. Rising atmospheric temperature (also in oceans & upper atmosphere) Rising sea level Reductions in NH snow cover Source: IPCC 2007 WG1, Figure SPM.3

6. Hansen et al, 2005 copied from UCS, http://www.ucsusa.org/global_warming/science_and_impacts/science/global-warming- human.html

7. Upper: Comparison of changes relative to 1900 in 5- year moving average of observed global mean surface temperature with simulated temperature from DOE PCM model. Lower: Model simulations of the individual effects of greenhouse gases, solar radiation, stratospheric and tropospheric ozone changes, volcanic emissions and sulfate emissions. Source: Meehl et al, 2004.

8. Models vs observations Human + natural forcings Natural forcings only Source: IPCC 2007 WG1 (Figure 9.5)

9. IPCC 2007, Fig 9.1. Zonal mean atmospheric temperature change, 1890 - 1999. a) solar, b) volcanoes, c) ghgs, d) trop. & strat. ozone, e) sulfate aerosol, f) all forcings

10. IPCC (2007), chapter 10, Figure 10.8. Multi-model mean annual surface warming relative to 1980-1999

12. IPCC (2007), Figure 5, WG1 SPM

14. IPCC (2007), chapter 10, Figure 10.8. Multi-model mean annual surface warming relative to 1980-1999

15. IPCC (2007), Figure 7 SPM. Multi-model average changes in DJF and JJA precipitation for 2090-2099 relative to 1980-1999.