1. Climate Change: General Introduction (Basic Introduction for Students with Some Science Knowledge) Richard B. Rood Cell: 301-526-8572 2525 Space Research Building (North Campus) rbrood@umich.edu http://aoss.engin.umich.edu/people/rbrood February 4, 2015

2. Some Basic References Intergovernmental Panel on Climate Change –IPCC (2007) Working Group 1: Summary for Policy MakersIPCC (2007) Working Group 1: Summary for Policy Makers –IPCC (2013) Working Group 1: Summary for Policy MakersIPCC (2013) Working Group 1: Summary for Policy Makers Spencer Weart: The Discovery of Global Warming Carbon dioxide greenhouse effect: http://www.aip.org/history/climate/co2.htm http://www.aip.org/history/climate/co2.htm Simple climate models http://www.aip.org/history/climate/simple.htm http://www.aip.org/history/climate/simple.htm Paul Edwards: A Vast Machine Rood –Rood Climate Change ClassRood Climate Change Class Reference list from course –Rood Blog Data BaseRood Blog Data Base Naomi Oreskes, Why Global Warming Scientists are Not Wrong

3. Climate Change in a Nutshell How and what do we know? Increase of carbon dioxide Some predictions Some observations (and attribution) How do we organize our responses? Reading about 4 degrees of warming –New et al. 2010, Phil. Trans. Roy. Soc.New et al. 2010, Phil. Trans. Roy. Soc.

4. Starting point: Scientific foundation The scientific foundation of our understanding of the Earth’s climate is based on budgets of energy, mass, and momentum. (Conservation principles) The scientific foundation of our understanding of the Earth’s climate is based on an enormous and diverse number of observations.

5. Starting point: A fundamental conclusion Based on the scientific foundation of our understanding of the Earth’s climate, we observe that with virtual certainty –The average global temperature of the Earth’s surface has increased due to the human- caused addition of gases into the atmosphere that hold heat close to the surface.

6. Starting point: A fundamental conclusion Based on the scientific foundation of our understanding of the Earth’s climate, we predict with virtual certainty –The average global temperature of the Earth’s surface will continue to rise because of the continued increase of human-caused addition into the atmosphere of gases that hold heat close to the surface. –Historically stable masses of ice on land will melt. –Sea level will rise. –The weather will change.

7. Scientific Approach Climate science is observationally based Climate change is computational science –Relies on models

8. Models are an Important Part of Climate Science What is a Model? Model –A work or construction used in testing or perfecting a final product. –A schematic description of a system, theory, or phenomenon that accounts for its known or inferred properties and may be used for further studies of its characteristics. Numerical Experimentation –Given what we know, can we predict what will happen, and verify that what we predicted would happen, happened?

9. Scientific Investigation OBSERVATIONSTHEORY PREDICTION PastFuturePresent Understanding Processes Evaluation, Verification PredictionsProjections Time

10. Summary Points: Science Theory / Empirical Evidence CO 2 and Water Vapor Hold Heat Near Surface Correlated Observations CO 2 and Temperature Observed to be strongly related on long time scales (> 100 years) CO 2 and Temperature not Observed to be strongly related on short time scales (< 10 years) Observations CO 2 is Increasing due to Burning Fossil Fuels Theory / Conservation Principle Mass and Energy Budgets  Concept of “Forcing” Prediction Earth Will Warm Validation Evaluation Consequences Land Use / Land Change Other Greenhouse Gases Aerosols Internal Variability Feedbacks Air Quality “Abrupt” Climate Change

11. Conservation principle: Energy Energy from the Sun Energy emitted by Earth (proportional to T) Earth at a certain temperature, T Stable Temperature of Earth could change from how much energy (production) comes from the sun, or by changing how we emit energy.

12. The first place that we apply the conservation principle is energy We reach a new equilibrium

13. The first place that we apply the conservation principle is energy We reach a new equilibrium Changes in orbit or solar energy changes this

14. Conservation principle: Energy Energy from the Sun Earth at a certain temperature, T Add some detail: Surface Insulating Blanket

15. The first place that we apply the conservation principle is energy We reach a new equilibrium Changing a greenhouse gas changes this

16. Some basics

17. Observed Increase of Atmospheric Carbon Dioxide (CO 2 ) Data and more information Primary increase comes from burning fossil fuels – coal, oil, natural gas

18. The yearly cycle of CO 2

19. Presentation of some results These are drawn from the Reports of the Intergovernmental Panel on Climate Change. I deliberately mix graphs from reports in 2001, 2007, and 2013. The messages from these reports are quite similar, which is a measure of Intergovernmental Panel on Climate Change –Consistent measure –Stable scientific understanding

20. IPCC (2007) projections for the next 100 years.

21. Projected Global Temperature Trends: 2100 2071-2100 temperatures relative to 1961-1990. Special Report on Emissions Scenarios Storyline B2 (middle of the road warming). IPCC 2001

22. Observed Temperature Anomaly in 2005 http://data.giss.nasa.gov/gistemp/2005/ http://data.giss.nasa.gov/gistemp/2005/ See Also: Osborn et al., The Spatial Extent of 20th-Century Warmth in the Context of the Past 1200 Years, Science, 311, 841-844, 2006

23. IPCC 2013: Observed Temperature Rood: What would happen if we stopped emitting now? What does this mean for design and engineering?

24. IPCC 2007: The last ~100 years

25. Fig. 2.5. (State of Climate 2009) Time series from a range of indicators that would be expected to correlate strongly with the surface record. Note that stratospheric cooling is an expected consequence of greenhouse gas increases. A version of this figure with full references is available at www.ncdc.noaa.gov/bams-state-of-climate /.State of Climate 2009 www.ncdc.noaa.gov/bams-state-of-climate / Correlated behavior of different parameters

26. Quick Summary: IPCC(2013)

27. Length of Growing Season From Ranga B. Myneni, Boston University

28. Summary In Progress: Observations Observations of climate change (global warming) –Average surface temperature of planet is increasing –Ice is melting Glaciers Ice sheets –Sea level is rising Ocean is warming up From the melting ice –Weather is changing Coherent and convergent evidence

29. Summary In Progress: Projections Observations are consistent model projections –Past century –Evolving Model projections –Planet will warm –Ice will melt –Sea level will rise –Weather will change

30. Summary In Progress: Uncertainty Identified major categories of uncertainty –Scenario – future emissions –Model – deficiencies in simulation capability –Observational – quality of observations, inability to completely observe –Dynamic variability – internal variability due to transfer of energy between components of a complex system

31. Summary in Progress: Attribution Have suggested several aspects of extent and attribution of warming to greenhouse gases –Spatial distribution of warming –Decrease of temperature in the stratosphere –Changes in growing season –Changes in seasonal cycle of carbon dioxide –Warming in the ocean –….

32. What parameters/events do we care about? Temperature Water –Precipitation –Evaporation –Humidity Air Composition –Air quality –Aerosols –Carbon dioxide Winds Clouds / Sunlight Droughts Floods Extreme Weather The impact of climate change is Water for Ecosystems Water for People Water for Energy Water for Physical Climate

33. Science, Mitigation, Adaptation Framework Mitigation is controlling the amount of CO 2 we put in the atmosphere. Adaptation is responding to changes that might occur from added CO 2 It’s not an either / or argument.

34. Stabilization / Total burden of Greenhouse Gases Have this notion of controlling emissions to stabilize the concentration of CO 2 in the atmosphere at some value. –That is, there was some value of emissions that would match the loss of CO 2 into the plants, soil and oceans. –However, CO 2 is exchanged between these reservoirs, and it takes a very long time for CO 2 amounts to decline. We know that the CO 2 that we emit will be with us essentially forever. Therefore, it is the total amount that we emit, rather than controlling emissions. –Arguably, we get to emit 1 trillion tons before climate change is “dangerous” –“Dangerous” = 2 degrees C average surface warming

35. Some Points Science-based conclusions –The surface of the Earth has warmed and this warming is consistent with increasing greenhouse gases. CO 2 is most important. –The Earth will continue to warm. –The concept of “stabilization” of CO 2 is challenged by the consideration of ocean- land-atmosphere time scales Accumulated carbon dioxide is important. 1 trillion tons  440 ppm

36. Some Points Analysis and Opinion –Probability of stabilizing at less than 440, 560 … ppm is very small. If we decide to stabilize at 350, 440, then we need to figure out how to remove CO 2 from the atmosphere.

37. Some Points Analysis and Opinion –We need to start to plan for a world that is on average, warmer than the 2 degrees C that we have deemed as the threshold of “dangerous”. –We have an enormous opportunity provided by predictions of climate change. We have the choice of whether or not to take advantage of this opportunity on personal, professional, local, national, and international levels. The world 4 degrees warmer: January 13, 2011 issue of The Philosophical Transactions of the Royal SocietyThe Philosophical Transactions of the Royal Society

38. Some Other References for the Interested Rood –Rood Blog “Just Temperature”Rood Blog “Just Temperature” –Rood Blog: Arctic Oscillation and Cold Times in Eastern North AmericaRood Blog: Arctic Oscillation and Cold Times in Eastern North America –Rood Blog: Trillion Tons of Carbon DioxideRood Blog: Trillion Tons of Carbon Dioxide –Rood Blog: Warming HiatusRood Blog: Warming Hiatus Lemos and Rood (2010) Koshland Science Museum: Global Warming