Lecture #7 Integrated Assessment of Climate and Carbon Cycle

1. ATMOS 397G Biogeochemical Cycles and Global Change Lecture #7 Integrated Assessment of Climate and Carbon Cycle Atul K. Jain Department of Atmospheric Sciences University of Illinois, Urbana, IL email: jain@atmos.uiuc.edu

2. How Much is a % Contribution of CO2 in the Atmosphere • 25% • 10% • 5% • 1% or less

3. Why Model The Carbon Cycle • Increasing atmospheric CO2 content may significantly alter Earth's climate and biosphere in the next century • To predict climate and its impacts, we need to be able to predict future CO2 concentrations

4. 1000 1200 1400 1600 1800 2000 CO2 is the Single Most Important GHGObserved Atmospheric CO2 Concentration(1000-2000)

5. Land Use Fossil Fuel Human Activities Perturb Natural Carbon Cycle

6. Carbon Cycle Modeling • The ability to predict the response of the carbon cycle to anthropogenic emissions relies on the: • Understanding of Carbon Cycle Mechanisms • Ocean transport and chemistry, and, air/sea exchange • plant physiology and soil processes • CO2 & Nitrogen Fertilization • Forest regrowth • Response to climate change • Measured behavior of the past carbon cycle • CO2 Fossil Fuel and Cement emissions • Observed CO2 concentration • Observed distribution of carbon isotopes (12C, 13C, 14C)

7. Atmosphere 3.2 …are leading to a build up of CO2 in the atmosphere. 750 63 6.3 Fossil Deposits About 16,000 3 1.6 60 Plants Fossil emissions ... 500 Soil 91.7 90 2000 1.7 …and land clearing in the tropics... Surface Ocean 1,000 Intermediate & Deep Ocean 38,000 IPCC (2001) Industrial Society & the Global Carbon CycleUnits: Gt C and Gt C y-1

8. Model Validation   13C Evidence in the Atmosphere and Ocean Points to Link Between Human-Related Emissions and CO2 Rise Jain et al. (1996)

9. 1.6 ± 0.8 6.3 ± 0.6 3.2 ± 0.2 1.7 ± 0.5 3 ± ??? Global CO2 Budget (GtC/yr) Based on Atmospheric CO2 and O2 Data 1990s 1980s • The global CO2 budget is usually defined as the mass balance among sources and sinks of CO2 produced by human activities. • Balancing the global CO2 budget requires a large unidentified (“missing”) carbon sink on land. • (The transfers shown (in metric tones of carbon per year) represent the CO2 budget for the 1980’s and 1990’s as estimated by the IPCC (1996 and 2001).

10. Rate of increase of CO2 Natural Transfers Fluctuate over Short Time Scale • Assessment of the Global CO2 Budget Requires Long Term Measurements and Models

11. ISAM Estimated CO2 Concentrations for IS92a Scenario

12. GREENHOUSE GAS EMISSIONS SCENARIOS • Purposes: • to develop an understanding of how human-related emissions will affect future climate • to enable us to look ahead & evaluate potential impacts for the range of possible future changes in climate • to be able to accurately compare present GHG emission reduction costs with future damages

13. Future Projections • Major Uncertainties • Socioeconomic (Future Emissions SRES Scenarios) • Carbon Cycle (Resulting CO2 Concentration) and • Climate Sensitivity (ºC for 2CO2) Based on ISAM

14. Impact of Stabilizing Emissions versus Stabilization Concentrations of CO2

15. The Challenge of Stabilization of Atmospheric Concentrations of Carbon Dioxide • Emissions of CO2 due to fossil fuel burning will be the dominant influence on atmospheric CO2 in the 21st century • Stabilization of CO2 at twice the pre-industrial level will require emissions to drop to below 1990 levels in less than 50 years. • Emissions will need to continue to decrease steadily thereafter to a very small fraction of current emissions. IPCC (2001, Based on ISAM)

16. WRE Range of Cumulative Emission Cumulative Carbon Emission Ranges for WRE Scenarios (2100)

17. EMISSIONS Socio-economic + energy analyses and modeling CONCENTRATIONS Carbon Cycle & Chemical transport models RADIATIVE FORCING Radiative transfer models CLIMATE CHANGE A-O-CIRCULATION A-O Models IMPACTS A Grand Challenge: Study Feedbacks Throughout The Earth System In the science and policy world …

18. Integrated Assessment

19. Tying it all together: The Concept of Integrated Assessment Modeling (IAM) • Purpose: • to interface science with policy • to provide information of use to decision-makers, not just for the sake of increasing knowledge for knowledge’s sake alone • to provide insights that cannot be easily derived from individual component models

20. Modeling the Earth-Climate System: Components

21. Integrated Assessment Modeling • “Integrated” refers to: • the completeness of causal links cycle coverage • the inclusion of feedback loops within and between cause-effect chains • the bringing together of information & analysis from disparate disciplines • “Assessment” refers to: • the focus of the models on evaluation and assessment of human & natural contributions and responses to climate change

22. What would the ideal IAM look like? • It would: • model the complete causal chain, including all feedbacks • have an interface that could be used interactively by a reasonably educated policy-maker on their own desktop PC • have results that don’t differ significantly from a hypothetical IAM made of the most comprehensive models available

23. The Integrated Science Assessment Model (ISAM) • ISAM is: • a deterministic projection, policy evaluation model • capable of evaluating climatic impacts of one policy decision at a time • a process-oriented model • has a modular structure with sub-models being simplified versions of models from different scientific disciplines, with standardized assumptions

24. BIOSPHERE Agricultural Land Use Model EMISSIONS PNNL MiniCam Model GHG emissions from industrial & energy-related sources CO2 fluxes from land use change CHEMICAL TRANSPORT 2D Atmospheric Chemical Transport Box Model CARBON CYCLE 2D Coupled Atmosphere-Ocean-Biosphere Model Concentrations of GHG,aerosols and other radiatively active species Carbon dioxide concentrations CLIMATE MODEL 2D Radiative Transfer Model 2D Atmosphere-Ocean-Land Moisture & Energy Balance Model Changes in global temperature, precipitation and sea level IMPACT ASSESSMENT STUDIES Integrated Science Assessment Model (ISAM)Earth System Model of Intermediate Complexity

25. Integrated Science Assessment Model (ISAM)as Tool for Scientific and Policy Analysis • Use all key Climate System Components and Feedbacks at an appropriate level of detail; • Account sub-grid climate processes by using empirical relationships to approximate net effects; • Approximate the effects of various physical and chemical processes based on AOGCM and CTM • Design to Upgrade as knowledge improves; • Evaluate Chemical and Climate Feedback Effects on Policy Developments; • Treat Uncertainty as an Essential Feature; • Global in scope, but resolve regional distribution.

26. GOAL - ISAM The development of an ideal tool based on solid science to increase our understanding of earth system feedbacks and to address multi-dimensional science and policy issues related to climate change.

27. Global-Annual Mean Versionof Integrated Science Assessment Model (ISAM)

28. ISAM WWW INTERFACEhttp://isam.atmos.uiuc.edu/isam • Purpose: • To make a state-of-the-art integrated assessment model available to the general public in a user-friendly format

29. ISAM Interface - Objectives • To give students/Educators/Policy Makers a tool for: • understanding the science of global change • using ISAM students see how physical processes and parameters in the climate system determine its behavior • understanding the long-term consequences of near-term policy choices • model outputs show long residence times of greenhouse gases in the atmosphere • understanding how policy makers assess the implications of their decisions • students use a model identical to that used by policy makers in forming greenhouse gas emissions policies

30. WWW INTERFACE OF ISAM(http://isam.atmos.uiuc.edu/isam) • This Interface Enables the User to • Run the ISAM on the Web Using an Intuitive Menu System • Alter the Various Physical Formulations of ISAM • Construct Scenariosof Greenhouse Gas and aerosol emissions • Assess their Impacton the Global Climate and on Sea Level Results are Presented as Graphs and Tables

31. Users of Our Web Site • Students of climate, and climate change, investigating the past and future effects of anthropogenic climate forcings. • Students of public policystudying the implications of proposed greenhouse-gas mitigation strategies. • Educatorspreparing course material on the science of global climate change and the implications of greenhouse-gas mitigation strategies. • Policy makers, in both government and the private sector, seeking projections of how their decisions will affect future greenhouse-gas concentrations and climate change.

32. Model Inputs • Step 1: Model Formulation for the Steady State: • Use default model settings or alter parameter values Question to answer: What are the implications of different values for climate sensitivity? • Step 2: Model Calculations of the Greenhouse Effect from Pre-Industrial Times into the Future • Run the model based on the Historical Observed Data, 1765-1990 Question to answer: How well does the model reproduce past climate change? How does this depend on model parameters? • Prescribe the Future Emission Scenario for Dates after 1990 a) Select IPCC (Intergovernmental Panel on Climate Change) Scenarios for 1990-2100... OR... Specify emissions of major greenhouse gases (CO2, CH4, N2O, CFCs, SO2) in key years. (b) Select end year of calculation (> 1995)

33. Model Output • Results Available as Graphs and Tables include: • Temperature Change and Rate of Temperature Change • Sea Level Change and Rate of Sea Level Change • Historical CO2 Emissions, Fluxes, and Atmospheric Concentrations • Future Emissions of Major Greenhouse Gases (CO2, CH4, CO, OH, N2O, CFCs, and SO2) • Concentrations of Major Greenhouse Gases • Total Tropospheric Chlorine and Ozone Changes • Radiative Forcings for Major Greenhouse Gases and Aerosols

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