Integrated Assessment of Climate
Change in the United States 1979 toPresent…And, Into the Future
Jae Edmonds
29th Asia Integrated Modeling Meeting
14 September 2023
Presented in remembrance of the 20th anniversary of the passing of our good friend and colleague,
Tsuneyuki Morita
Thanks to Ron Sands for helpful input to this presentation.
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U.S. IAMs Have Been Informing Decisions for
Four Decades
Early work dates to the 1980’s.
Nordhaus, William D.
"Efficient use of energy
resources." (1979).
Edmonds, Jae, and J. M. Reilley.
DRAFT PRESENTATION—DONOT QUOTE, SUBJECT"Global energy-assessing
the TO CHANGEfuture." (1985).

The original question was:“Will the concentration of CO2
double by the year 2000?”
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In the 1990’s U.S. IAMs Helped Shape the Kyoto
Protocol: Where and When Flexibility

Two major concepts
helped shape the Kyoto
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Protocol of 1997—
Where and When
Flexibility

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In the 1990’s U.S. IAMs Helped Shape the KyotoProtocol: Where and When Flexibility
Where flexibility meant Emissions Trading.

BASE CASE

WHERE
CASE

Cost Index (Base Case=100)

Flexibility in WHEN
Emissions are Reduced
YESNO

Flexability in WHERE
Emissions are Reduced
NO
YES

100
90807060

No
Flex
Case
WhenCase

504030“Where and whenflexibilities”
introduced into thenegotiations COP2,Geneva, July 1996.

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20WHENCASE

BOTH CASE

100CaseBoth Case

Wigley, T.M., Richels, R. and Edmonds, J.A., 1996.
Economic and environmental choices in thestabilization of atmospheric CO2concentrations. Nature, 379(6562), pp.240-243.
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In the 2000’s U.S. IAMs Helped Introduce the Ideaof Net-zero Emissions
Net-zero emissions is a key concept
in the Paris Agreement of 2015.

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In the 2000’s U.S. IAMs
Introduced Identified theCentral Role of Electrificationin Deep Decarbonization
Edmonds, J., T. Wilson, M. Wise, and J.
Weyant. 2006. Electrification of theDRAFT PRESENTATION—DONOTEmissions
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Economy and CO2Mitigation,
Journal of Environmental Economics andPolicy Studies. (2006) 7:175-203.

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In the 2010’s IAMs Helped Shape the U.S. LongTerm Strategy

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In the 2020’s U.S. IAMs Continue to Help Shape theU.S. Long-Term Strategy

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8The Inflation Reduction Act (IRA) was passed in August of 2022.
U.S. IAMs helped shape the overarching goals of the IRA but notthe details. IAMs are playing a role in assessing the IRA.

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The Future of U.S. IAMs Is Full of Challenges andPromise
Future IAM development will be shaped by society’s questions.
The challenge is to build and maintain interdisciplinary groups
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the worldwithdeep
expertise in the full range of fields tobe integrated, and the ability to develop, maintain and deploy thecomputational tools, infrastructure, and the supporting internallyconsistent synthetic data sets to continue the work.
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