Sensitivity of direct global warming potentials to key uncertainties

Donald J Wuebbles, Atul Jain, K. O. Patten, K. E. Grant

Research output: Contribution to journalArticlepeer-review

Abstract

The concept of global warming potential was developed as a relative measure of the potential effects on climate of a greenhouse gas as compared to CO2. In this paper a series of sensitivity studies examines several uncertainties in determination of Global Warming Potentials (GWPs). For example, the original evaluation of GWPs for the Intergovernmental Panel on Climate Change (IPCC, 1990) did not attempt to account for the possible sinks of carbon dioxide (CO2) that could balance the carbon cycle and produce atmospheric concentrations of CO2 that match observations. In this study, a balanced carbon cycle model is applied in calculation of the radiative forcing from CO2. Use of the balanced model produces up to 21% enhancement of the GWPs for most trace gases compared with the IPCC (1990) values for time horizons up to 100 years, but a decreasing enhancement with longer time horizons. Uncertainty limits of the fertilization feedback parameter contribute a 20% range in GWP values. Another systematic uncertainty in GWPs is the assumption of an equilibrium atmosphere (one in which the concentration of trace gases remains constant) versus a disequilibrium atmosphere (one in which the concentration of trace gases varies with time). The latter gives GWPs that are 19 to 32% greater than the former for a 100 year time horizons, depending upon the carbon dioxide emission scenario chosen. Five scenarios are employed: constant-concentration, constant-emission past 1990 and the three IPCC (1992) emission scenarios. For the analysis of uncertainties in atmospheric lifetime (τ) the GWP changes in direct proportion to τ for short-lived gases, but to a lesser extent for gases with τ greater than the time horizontal for the GWP calculation.

Original languageEnglish (US)
Pages (from-to)265-297
Number of pages33
JournalClimatic Change
Volume29
Issue number3
DOIs
StatePublished - Mar 1 1995
Externally publishedYes

ASJC Scopus subject areas

  • Global and Planetary Change
  • Atmospheric Science

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