Skip to main content
Menu

Main navigation

  • About
    • Annual Reports
    • Leadership
    • Jobs
    • Student Programs
    • Media Information
    • Store
    • Contact
    LOADING...
  • Experts
    • Policy Scholars
    • Adjunct Scholars
    • Fellows
  • Events
    • Upcoming
    • Past
    • Event FAQs
    • Sphere Summit
    LOADING...
  • Publications
    • Studies
    • Commentary
    • Books
    • Reviews and Journals
    • Public Filings
    LOADING...
  • Blog
  • Donate
    • Sponsorship Benefits
    • Ways to Give
    • Planned Giving
    • Meet the Development Team

Issues

  • Constitution and Law
    • Constitutional Law
    • Criminal Justice
    • Free Speech and Civil Liberties
  • Economics
    • Banking and Finance
    • Monetary Policy
    • Regulation
    • Tax and Budget Policy
  • Politics and Society
    • Education
    • Government and Politics
    • Health Care
    • Poverty and Social Welfare
    • Technology and Privacy
  • International
    • Defense and Foreign Policy
    • Global Freedom
    • Immigration
    • Trade Policy
Live Now

Cato at Liberty


  • Blog Home
  • RSS

Email Signup

Sign up to have blog posts delivered straight to your inbox!

Topics
  • Banking and Finance
  • Constitutional Law
  • Criminal Justice
  • Defense and Foreign Policy
  • Education
  • Free Speech and Civil Liberties
  • Global Freedom
  • Government and Politics
  • Health Care
  • Immigration
  • Monetary Policy
  • Poverty and Social Welfare
  • Regulation
  • Tax and Budget Policy
  • Technology and Privacy
  • Trade Policy
Archives
  • April 2021
  • March 2021
  • February 2021
  • January 2021
  • December 2020
  • November 2020
  • October 2020
  • September 2020
  • August 2020
  • July 2020
  • June 2020
  • May 2020
  • April 2020
  • March 2020
  • February 2020
  • January 2020
  • December 2019
  • November 2019
  • October 2019
  • September 2019
  • August 2019
  • July 2019
  • June 2019
  • May 2019
  • April 2019
  • March 2019
  • February 2019
  • January 2019
  • December 2018
  • November 2018
  • October 2018
  • September 2018
  • August 2018
  • July 2018
  • June 2018
  • May 2018
  • April 2018
  • March 2018
  • February 2018
  • January 2018
  • December 2017
  • November 2017
  • October 2017
  • September 2017
  • August 2017
  • July 2017
  • June 2017
  • May 2017
  • April 2017
  • March 2017
  • February 2017
  • January 2017
  • December 2016
  • November 2016
  • October 2016
  • September 2016
  • August 2016
  • July 2016
  • June 2016
  • May 2016
  • April 2016
  • March 2016
  • February 2016
  • January 2016
  • December 2015
  • November 2015
  • October 2015
  • September 2015
  • August 2015
  • July 2015
  • June 2015
  • May 2015
  • April 2015
  • March 2015
  • February 2015
  • January 2015
  • December 2014
  • November 2014
  • October 2014
  • September 2014
  • August 2014
  • July 2014
  • June 2014
  • May 2014
  • April 2014
  • March 2014
  • February 2014
  • January 2014
  • December 2013
  • November 2013
  • October 2013
  • September 2013
  • August 2013
  • July 2013
  • June 2013
  • May 2013
  • April 2013
  • March 2013
  • February 2013
  • January 2013
  • December 2012
  • November 2012
  • October 2012
  • September 2012
  • August 2012
  • July 2012
  • June 2012
  • May 2012
  • April 2012
  • March 2012
  • February 2012
  • January 2012
  • December 2011
  • November 2011
  • October 2011
  • September 2011
  • August 2011
  • July 2011
  • June 2011
  • May 2011
  • April 2011
  • March 2011
  • February 2011
  • January 2011
  • December 2010
  • November 2010
  • October 2010
  • September 2010
  • August 2010
  • July 2010
  • June 2010
  • May 2010
  • April 2010
  • March 2010
  • February 2010
  • January 2010
  • December 2009
  • November 2009
  • October 2009
  • September 2009
  • August 2009
  • July 2009
  • June 2009
  • May 2009
  • April 2009
  • March 2009
  • February 2009
  • January 2009
  • December 2008
  • November 2008
  • October 2008
  • September 2008
  • August 2008
  • July 2008
  • June 2008
  • May 2008
  • April 2008
  • March 2008
  • February 2008
  • January 2008
  • December 2007
  • November 2007
  • October 2007
  • September 2007
  • August 2007
  • July 2007
  • June 2007
  • May 2007
  • April 2007
  • March 2007
  • February 2007
  • January 2007
  • December 2006
  • November 2006
  • October 2006
  • September 2006
  • August 2006
  • July 2006
  • June 2006
  • May 2006
  • April 2006
  • Show More
April 9, 2014 1:57PM

Social Cost of Carbon Inflated by Extreme Sea Level Rise Projections

By Patrick J. Michaels and Paul C. "Chip" Knappenberger

SHARE

Global Science Report is a feature from the Center for the Study of Science, where we highlight one or two important new items in the scientific literature or the popular media. For broader and more technical perspectives, consult our monthly “Current Wisdom.”




As we mentioned in our last post, the federal Office of Management and Budget (OMB) is in the process of reviewing how the Obama administration calculates and uses the social cost of carbon (SCC). The SCC is a loosey-goosey computer model result that attempts to determine the present value of future damages that result from climate change caused by pernicious economic activity. Basically, it can be gamed to give any result you want.

We have filed a series of comments with the OMB outlining what is wrong with the current federal determination of the SCC used as the excuse for more carbon dioxide restrictions. There is so much wrong with the feds' SCC, that we concluded that rather than just update it, the OMB ought to just chuck the whole concept of the social cost of carbon out the window and quickly close and lock it.

We have discussed many of the problems with the SCC before, and in our last post we described how the feds have turned the idea of a “social cost” on its head. In this installment, we describe a particularly egregious fault that exists in at least one of the prominent models used by the federal government to determine the SCC: The projections of future sea-level rise (a leading driver of future climate change-related damages) from the model are much higher than even the worst-case mainstream scientific thinking on the matter. This necessarily results in an SCC determination that is higher than the best science could possibly allow.

The text below, describing our finding, is adapted from our most recent set of comments to the OMB.

The Dynamic Integrated Climate-Economy (DICE) model, developed by Yale economist William Nordhaus (2010a), is what is termed an “integrated assessment model” or, IAM. An IAM is computer model which combines economics, climate change and feedbacks between the two to project how future societies are impacted by projected climate change and ultimately to determine the social cost of carbon (i.e., how much future damage, in today’s monetary terms, occurs for each unit emission of carbon (dioxide)).

In examining the climate change output from the DICE model, we found that it projects a degree of future sea level rise that far exceeds mainstream projections and are unsupported by the best available science. The sea level rise projections from more than half of the future scenarios examined exceed even the highest end of the projected sea level rise by the year 2300 as reported in the Fifth Assessment Report (AR5) of the UN’s Intergovernmental Panel on Climate Change (see Figure 1).

Media Name: gsr_040914_fig1.jpg

Figure 1. Projections of sea level rise from the DICE model (the arithmetic average of the 10,000 Monte Carlo runs from each scenario) for the five scenarios examined by the federal interagency working group (colored lines) compared with the range of sea level rise projections for the year 2300 given in the IPCC AR5 (represented by the vertical blue bar). (DICE data provided by Kevin Dayaratna and David Kreutzer of the Heritage Foundation)

Interestingly, Nordhaus (2010b) recognizes that the DICE sea level rise projections are outside the mainstream climate view as expressed by the IPCC:

“The RICE [DICE] model projection is in the middle of the pack of alternative specifications of the different Rahmstorf specifications. Table 1 shows the RICE, base Rahmstorf, and average Rahmstorf. Note that in all cases, these are significantly above the IPCC projections in AR4.” [emphasis added]

The justification given for the high sea-level rise projections in the DICE model (Nordhaus, 2010) is that they well-match the results of a “semi-empirical” methodology employed by Rahmstorf (2007) and Vermeer and Rahmstorf (2009).

However, as we have pointed out, recent science has proven the “semi-empirical” approach to projecting future sea level rise unreliable. For example, Gregory et al. (2012) examined the assumption used in the “semi-empirical” methods and found them to be unsubstantiated. Gregory et al (2012) specifically refer to the results of Rahmstorf (2007) and Vermeer and Rahmstorf (2009):

The implication of our closure of the [global mean sea level rise, GMSLR] budget is that a relationship between global climate change and the rate of GMSLR is weak or absent in the past. The lack of a strong relationship is consistent with the evidence from the tide-gauge datasets, whose authors find acceleration of GMSLR during the 20th century to be either insignificant or small. It also calls into question the basis of the semi-empirical methods for projecting GMSLR, which depend on calibrating a relationship between global climate change or radiative forcing and the rate of GMSLR from observational data (Rahmstorf, 2007; Vermeer and Rahmstorf, 2009; Jevrejeva et al., 2010).

In light of these findings, the justification for the very high sea-level rise projections produced by the DICE model is not acceptable.

Given the strong relationship between sea-level rise and future damage built into the DICE model, there can be no doubt that the SCC estimates from the DICE model are higher than the best science can allow and consequently, should not be accepted by the OMB as a reliable estimate of the social cost of carbon.

We did not investigate the sea-level rise projections from the other two IAMs employed in the federal SCC determination, but such an analysis must be carried out prior to extending any confidence in the values of the SCC resulting from those models—confidence that we demonstrate cannot be assigned to the DICE determinations of the social cost of carbon.

References:

Gregory, J., et al., 2012. Twentieth-century global-mean sea-level rise: is the whole greater than the sum of the parts? Journal of Climate, 26, 4476-4499, doi:10.1175/JCLI-D-12-00319

Nordhaus, W. 2010a. Economic aspects of global warming in a post-Copenhagen environment. Proceedings of the National Academy of Sciences 107(26): 11721-11726.

Nordhaus, W., 2010b. Projections of Sea Level Rise (SLR), http://www.econ.yale.edu/~nordhaus/homepage/documents/SLR_021910.pdf

 

Related Tags
Energy and Environment

Stay Connected to Cato

Sign up for the newsletter to receive periodic updates on Cato research, events, and publications.

View All Newsletters

1000 Massachusetts Ave. NW
Washington, DC 20001-5403
202-842-0200
Contact Us
Privacy

Footer 1

  • About
    • Annual Reports
    • Leadership
    • Jobs
    • Student Programs
    • Media Information
    • Store
    • Contact
  • Podcasts

Footer 2

  • Experts
    • Policy Scholars
    • Adjunct Scholars
    • Fellows
  • Events
    • Upcoming
    • Past
    • Event FAQs
    • Sphere Summit

Footer 3

  • Publications
    • Books
    • Cato Journal
    • Regulation
    • Cato Policy Report
    • Cato Supreme Court Review
    • Cato’s Letter
    • Human Freedom Index
    • Economic Freedom of the World
    • Cato Handbook for Policymakers

Footer 4

  • Blog
  • Donate
    • Sponsorship Benefits
    • Ways to Give
    • Planned Giving
Also from Cato Institute:
Libertarianism.org
|
Humanprogress.org
|
Downsizinggovernment.org