eugene s. takle agronomy department geological and atmospheric science department

PROJECT TO INTERCOMPARE REGIONAL CLIMATE SIMULATIONS

Global Climate Change and Regional Impacts:

Are We Building the Right Kind of Drainage Structures to Handle Climate Change?

Eugene S. TakleAgronomy Department

Geological and Atmospheric Science Department

Iowa State University

Ames, Iowa 50011

[email protected]


Outline

Evidence for global climate change Future atmospheric carbon dioxide concentrations Simulations of global climate and future climate

change Implications for stream flow and

nutrient loss Summary

Carbon Dioxide and Temperature


2004


2004

2040


Stabilization at 550 ppm


“Business as Usual”(fossil intensive)

2100

?


Associated Climate Changes

Global sea-level has increased 1-2 mm/yr Duration of ice cover of rivers and lakes decreased by 2 weeks in N.

Hemisphere Arctic ice has thinned substantially, decreased in extent by 10-15% Reduced permafrost in polar, sub-polar, mountainous regions Growing season lengthened by 1-4 days in N. Hemisphere Retreat of continental glaciers on all continents Poleward shift of animal and plant ranges Snow cover decreased by 10% Earlier flowering dates Coral reef bleaching

Source: Intergovernmental Panel on Climate Change, 2001 Report

Mann, M. E., R. S. Bailey, and M. K. Hughes, 1999: Geophysical Research Letters 26, 759.

Source: IPCC, 2001: Climate Change 2001: The Scientific Basis

Observed summer (June-July-August) daily mean temperature changes (K) between 1976-2000 (Adapted from Folland et al. [2001]).

Hansen, Scientific American, March 2004

Source: Jerry Meehl, National Center for Atmospheric Research

Source: National Center for Atmospheric Research

Source: National Center for Atmospheric Research

The planet is committed toa warming over the next 50 years regardless of political decisions

Source: Intergovernmental Panel on Climate Change, 2001 Report

Amount of warming isin question, but all modelsproject a warming

Climate Change Projected for 2100

Rapid Economic Growth

Slower Economic Growth

IPCC Summary for Policy Makers

An increasing body of observations gives a collective picture of a warming world and other changes in the climate system

Emissions of greenhouse gases and aerosols due to human activities continue to alter the atmosphere in ways that are expected to affect the climate

IPCC Summary for Policy Makers, cont’d

Confidence in the ability of models to project future climate has increased

There is new and stronger evidence that most of the warming observed over the last 50 years is attributable to human activities

IPCC Summary for Policy Makers, cont’d

Anthropogenic climate change will persist for many centuries

Further action is required to address remaining gaps in information and understanding


Climate Surprises

Breakdown of the ocean thermohaline circulation (Greenland melt water)

Breakoff of the West Antarctic Ice Sheet


Regional Climate Change for the US Midwest

Observed and projected changes in climate

Impact on water quantity and water quality

Policy implications

Changes in Daily Maximum Temperature Projected for 2040 by a Regional Climate Model

Changes in Daily Minimum Temperature Projected for 2040 by a Regional Climate Model

“Warming Hole”

TTmaxmax (JJA) (JJA)˚C

For the Midwest Warming will be greater for winter than summer Warming will be greater at night than during the

day A 3oF rise in summer daytime temperature triples

the probability of a heat wave Growing season will be longer (8-9 days longer

now than in 1950) More precipitation Likely more soil moisture in summer More rain will come in intense rainfall events Higher stream flow, more flooding

Sub-Basins of theSub-Basins of theUpper MississippiUpper MississippiRiver BasinRiver Basin

119 sub-basins

Outflow measuredat Grafton, IL

Approximately oneobserving stationper sub-basin

Approximately onemodel grid pointper sub-basin


Soil Water Assessment Tool (SWAT)

Long-term, continuous watershed simulation model (Arnold et al,1998)

Assesses impacts of climate and management on yields of water, sediment, and agricultural chemicals

Physically based, including hydrology, soil temperature, plant growth, nutrients,

pesticides and land management Daily time steps

Validation of SWAT:Validation of SWAT:Annual Stream Flow at Grafton, ILAnnual Stream Flow at Grafton, IL

Validation of SWAT:Validation of SWAT:Monthly Stream Flow at Grafton, ILMonthly Stream Flow at Grafton, IL

Ten-Year Mean Precipitation Generated by the RegCM2 Ten-Year Mean Precipitation Generated by the RegCM2 Regional Climate Model Driven with HadCM2 Regional Climate Model Driven with HadCM2

Global Model Results for the Contemporary and Global Model Results for the Contemporary and

Future Scenario (2040s) ClimateFuture Scenario (2040s) Climate

Ten-Year Mean Monthly Stream Flow Generated by the Ten-Year Mean Monthly Stream Flow Generated by the RegCM2 Regional Climate Model Driven RegCM2 Regional Climate Model Driven

with HadCM2 Global Model Results for the with HadCM2 Global Model Results for the Contemporary and Future Scenario (2040s) ClimateContemporary and Future Scenario (2040s) Climate

Comparison of Simulated Stream Flow under Comparison of Simulated Stream Flow under Climate Change with Various Model BiasesClimate Change with Various Model Biases

Relation of Runoff to Precipitation Relation of Runoff to Precipitation for Various Climatesfor Various Climates


Regional Climate Modeling for Informing Policy on Water Quality

How does the combination of climate change and land use impact water quality?

Use nitrates and sediment as indicators What alternative land management

strategies will improve water quality? What policies need to be

implemented to achieve this water quality improvement?

Maquoketa Watershed

Scenario 1: all Agriculture

Scenario 2: all Forest

Scenario 3: N. half Agric. and S. half Forest.

Scenario 4: S. half Agric. and N. half Forest.

Scenario 5: Upper half Agric. and lower half Forest.

Scenario 6: Lower half Agric. and upper half Forest.

Scenario 7: Main channel basins - Agric.

Scenario 8: Main channel basins - Forest.


Improving Regional Climate Models

Project to Intercompare Regional Climate Simulations

Transferability Working Group of GEWEX


Summary

Regional climate models demonstrate sufficient skill to be useful for driving some climate impacts assessment models for the purpose of informing policy makers and decision-makers of vulnerabilities and opportunities associated with future climate change


For More Information

See my online Global Change course:

http://www.meteor.iastate.edu/gccourse

Contact me directly:

[email protected]

eugene s. takle agronomy department geological and atmospheric science department

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