Climate sensitivity distributions dependence on the possibility that models share biases

Research output: Contribution to journalArticle

20 Citations (Scopus)

Abstract

Uncertainty about biases common across models and about unknown and unmodeled feedbacks is important for the tails of temperature change distributions and thus for climate risk assessments. This paper develops a hierarchical Bayes framework that explicitly represents these and other sources of uncertainty. It then uses models' estimates of albedo, carbon cycle, cloud, and water vapor-lapse rate feedbacks to generate posterior probability distributions for feedback strength and equilibrium temperature change. The posterior distributions are especially sensitive to prior beliefs about models' shared structural biases: nonzero probability of shared bias moves some probability mass toward lower values for climate sensitivity even as it thickens the distribution's positive tail. Obtaining additional models of these feedbacks would not constrain the posterior distributions as much as narrowing prior beliefs about shared biases or, potentially, obtaining feedback estimates having biases uncorrelated with those impacting climate models. Carbon dioxide concentrations may need to fall below current levels to maintain only a 10% chance of exceeding official 28C limits on global average temperature change.

Original languageEnglish (US)
Pages (from-to)4395-4415
Number of pages21
JournalJournal of Climate
Volume23
Issue number16
DOIs
StatePublished - Aug 2010
Externally publishedYes

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climate
temperature
carbon cycle
albedo
climate modeling
water vapor
risk assessment
carbon dioxide
distribution
rate

ASJC Scopus subject areas

  • Atmospheric Science

Cite this

Climate sensitivity distributions dependence on the possibility that models share biases. / Lemoine, Derek M.

In: Journal of Climate, Vol. 23, No. 16, 08.2010, p. 4395-4415.

Research output: Contribution to journalArticle

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