Lecture #7 Integrated Assessment of Climate and Carbon Cycle Atul K. Jain Department of Atmospheric Sciences University of Illinois, Urbana, IL ATMOS 397G Biogeochemical Cycles and Global Change

How Much is a % Contribution of CO 2 in the Atmosphere  25%  10%  5%  1% or less

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

CO 2 is the Single Most Important GHG Observed Atmospheric CO2 Concentration ( )

Human Activities Perturb Natural Carbon Cycle Land Use Fossil Fuel

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  CO 2 & Nitrogen Fertilization  Forest regrowth  Response to climate change  Measured behavior of the past carbon cycle  CO2 Fossil Fuel and Cement emissions  Observed CO 2 concentration  Observed distribution of carbon isotopes ( 12 C, 13 C, 14 C)

Industrial Society & the Global Carbon Cycle Units: Gt C and Gt C y -1 Atmosphere Fossil Deposits Plants Soil Surface Ocean ,000 About 16, …are leading to a build up of CO 2 in the atmosphere. Fossil emissions... …and land clearing in the tropics... IPCC (2001) Intermediate & Deep Ocean 1,

  Jain et al. (1996) 13 C Evidence in the Atmosphere and Ocean Points to Link Between Human-Related Emissions and CO 2 Rise Model Validation

Global CO 2 Budget (GtC/yr) Based on Atmospheric CO 2 and O 2 Data The global CO 2 budget is usually defined as the mass balance among sources and sinks of CO 2 produced by human activities. Balancing the global CO 2 budget requires a large unidentified (“missing”) carbon sink on land. (The transfers shown (in metric tones of carbon per year) represent the CO 2 budget for the 1980’s and 1990’s as estimated by the IPCC (1996 and 2001). 1.6 ± ± ± ± 0.53 ± ??? 1990s 1980s

Natural Transfers Fluctuate over Short Time Scale Rate of increase of CO 2 Assessment of the Global CO 2 Budget Requires Long Term Measurements and Models

ISAM Estimated CO 2 Concentrations for IS92a Scenario

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

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

Impact of Stabilizing Emissions versus Stabilization Concentrations of CO 2

The Challenge of Stabilization of Atmospheric Concentrations of Carbon Dioxide IPCC (2001, Based on ISAM) Emissions of CO 2 due to fossil fuel burning will be the dominant influence on atmospheric CO 2 in the 21st century Emissions of CO 2 due to fossil fuel burning will be the dominant influence on atmospheric CO 2 in the 21st century Stabilization of CO 2 at twice the pre-industrial level will require emissions to drop to below 1990 levels in less than 50 years. Stabilization of CO 2 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. Emissions will need to continue to decrease steadily thereafter to a very small fraction of current emissions.

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

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

Integrated Assessment

Tying it all together: The Concept of Integrated Assessment Modeling (IAM) l 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

Modeling the Earth-Climate System: Components

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

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

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

Integrated Science Assessment Model (ISAM) Earth System Model of Intermediate Complexity EMISSIONS PNNL MiniCam Model GHG emissions from industrial & energy-related sources CHEMICAL TRANSPORT 2D Atmospheric Chemical Transport Box Model Concentrations of GHG,aerosols and other radiatively active species BIOSPHERE Agricultural Land Use Model CO2 fluxes from land use change CARBON CYCLE 2D Coupled Atmosphere- Ocean-Biosphere Model 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) as Tool for Scientific and Policy Analysis UUse all key Climate System Components and Feedbacks at an appropriate level of detail; AAccount sub-grid climate processes by using empirical relationships to approximate net effects; AApproximate the effects of various physical and chemical processes based on AOGCM and CTM DDesign to Upgrade as knowledge improves; EEvaluate Chemical and Climate Feedback Effects on Policy Developments; TTreat Uncertainty as an Essential Feature; GGlobal in scope, but resolve regional distribution.

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.

Global-Annual Mean Version of Integrated Science Assessment Model (ISAM)

ISAM WWW INTERFACE Purpose:  To make a state-of-the-art integrated assessment model available to the general public in a user-friendly format

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

WWW INTERFACE OF 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 Scenarios of Greenhouse Gas and aerosol emissions  Assess their Impact on the Global Climate and on Sea Level Results are Presented as Graphs and Tables

Users of Our Web Site Students of climate, and climate change, investigating the past and future effects of anthropogenic climate forcings. Students of public policy studying the implications of proposed greenhouse-gas mitigation strategies. Educators preparing 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.

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, 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 OR... Specify emissions of major greenhouse gases (CO2, CH4, N2O, CFCs, SO2) in key years. (b) Select end year of calculation (> 1995)

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 CO 2 Emissions, Fluxes, and Atmospheric Concentrations  Future Emissions of Major Greenhouse Gases (CO 2, CH 4, CO, OH, N 2 O, CFCs, and SO 2 )  Concentrations of Major Greenhouse Gases  Total Tropospheric Chlorine and Ozone Changes  Radiative Forcings for Major Greenhouse Gases and Aerosols

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