Lecture #7 Lecture #7 Integrated Assessment of Integrated Assessment of Climate and Carbon CycleClimate and Carbon Cycle

Atul K. Jain

Department of Atmospheric Sciences

University of Illinois, Urbana, ILemail: jain@atmos.uiuc.edu

ATMOS 397GBiogeochemical Cycles and Global Change

How Much is a % Contribution of CO2 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

COCO22 is the Single Most Important GHG is the Single Most Important GHGObserved Atmospheric CO2 ConcentrationObserved Atmospheric CO2 Concentration

(1000-2000)(1000-2000)

1000 1200 1400 1600 1800 2000

Human Activities Perturb Natural Human Activities Perturb Natural Carbon CycleCarbon Cycle

Land Use

Fossil Fuel

Carbon Cycle ModelingCarbon 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 exchangeplant physiology and soil processes CO2 & Nitrogen FertilizationForest regrowthResponse to climate change

Measured behavior of the past carbon cycleCO2 Fossil Fuel and Cement emissionsObserved CO2 concentrationObserved distribution of carbon isotopes (12C, 13C, 14C)

Industrial Society & the Global Carbon Cycle

Units: Gt C and Gt C y-1

Atmosphere

Fossil Deposits6.3

63

91.7

60

90

3.2

Plants

Soil

Surface Ocean

750

500

2000

38,000

About 16,0001.

6

…are leading to a build up of CO2

in the atmosphere.

Fossil emissions ...

…and land clearing in the tropics...

IPCC (2001)

Intermediate & Deep Ocean

1,000

3

1.7

Jain et al. (1996)

13C Evidence in the Atmosphere and Ocean Points to Link Between Human-Related Emissions and CO2 Rise

Model ValidationModel Validation

Global CO2 Budget (GtC/yr) Based on Atmospheric CO2 and O2 Data

• 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).

1.6 ± 0.8 6.3 ± 0.6 3.2 ± 0.2 1.7 ± 0.5 3 ± ???1990s1980s

Natural Transfers Fluctuate over Short Time Scale

2

4

6

8

Global(NOAA)

Cape Grim(CSIRO)

0

30

Fossil Fuel

Pinatubo

1955 1960 1965 1970 1975 1980 1985 1990 1995 2000

-30

CO2 GROWTH RATE

El Nino

La Nina

Mauna Loa(Scripps/NOAA)

(R J Francey, pers. Com)

Rate of increase of CO2

• Assessment of the Global CO2 Budget Requires Long Term Measurements and Models

ISAM Estimated CO2 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 ProjectionsFuture Projections

Major Uncertainties

• Socioeconomic (Future Emissions SRES Scenarios)

• Carbon Cycle (Resulting CO2 Concentration) and

• Climate Sensitivity (ºC for 2CO2)

Based on ISAM

Impact of Stabilizing Emissions versus Stabilization

Concentrations of CO2

The Challenge of Stabilization of Atmospheric The Challenge of Stabilization of Atmospheric Concentrations of Carbon DioxideConcentrations of Carbon Dioxide

IPCC (2001, Based on ISAM)

• • Emissions of COEmissions of CO22 due to due to fossil fuel burning will be the fossil fuel burning will be the dominant influence on dominant influence on atmospheric COatmospheric CO22 in the 21st in the 21st centurycentury

• • Stabilization of COStabilization of CO22 at twice at twice the pre-industrial level will the pre-industrial level will require emissions to drop to require emissions to drop to below 1990 levels in less below 1990 levels in less than 50 years.than 50 years.

•• Emissions will need to Emissions will need to continue to decrease steadily continue to decrease steadily thereafter to a very small thereafter to a very small fraction of current emissions.fraction of current emissions.

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

Human Activities

Energy UseLand Use(Deforestation)

Land SurfaceCharacteristics

FO

CU

S

Biodiversity Health EconomicActivity

Integrated Assessment

Physical/Chemical Effects

AtmosphericComposition

Climate,Including Ocean

HydrologicalCycle

Biological & Other Effects

Socioeconomic Effects

Agriculture NaturalEcosystem

Water Resources

Integrated Assessment

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

Modeling the Earth-Climate System:

Components

BiogeochemicalCycles

Atmospheric Chemistry

BiosphereHuman Activities

ClimateProcesses

•Temperature•Winds•Clouds, Precip.

Ocean ProcessesGases, aerosols

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 What would the ideal IAM look like?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 The Integrated Science Assessment Model (ISAM)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 modelhas 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

EMISSIONSPNNL MiniCam

ModelGHG emissions from industrial & energy-related

sources

CHEMICAL TRANSPORT2D Atmospheric 2D Atmospheric

Chemical Transport Box Chemical Transport Box ModelModel Concentrations of GHG,aerosols

andother radiatively active species

BIOSPHEREAgricultural Land Use Model

CO2 fluxes from land use change

CARBON CYCLE2D Coupled 2D Coupled

Atmosphere-Ocean-Atmosphere-Ocean-Biosphere ModelBiosphere ModelCarbon dioxide concentrations

CLIMATE MODEL2D Radiative Transfer Model2D Radiative Transfer Model

2D Atmosphere-Ocean-Land Moisture & Energy Balance2D Atmosphere-Ocean-Land Moisture & Energy Balance ModelModelChanges 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 - ISAMThe development of an ideal tool

based on solid scienceto increase our understanding

of earth system feedbacks and to address multi-dimensional

science and policy issues related to climate change.

Global-Annual MeanGlobal-Annual Mean Version Version of of Integrated Science Assessment Model Integrated Science Assessment Model

(ISAM)(ISAM)

ISAM WWW INTERFACEISAM WWW INTERFACE http://isam.atmos.uiuc.edu/isahttp://isam.atmos.uiuc.edu/isa

mm

• Purpose:To make a state-of-the-art

integrated assessment model available to the general public in a user-friendly format

ISAM Interface - ISAM Interface - ObjectivesObjectives

• 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 ISAMWWW INTERFACE OF ISAM

(http://isam.atmos.uiuc.edu/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 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 SiteUsers 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 InputsModel 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)

Model OutputModel 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

THE END