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Title: Unrealized Global Temperature Increase: Implications of Current Uncertainties

Abstract

Unrealized increase in global mean surface air temperature (GMST) may result from the climate system not being in steady state with forcings and/or from cessation of negative aerosol forcing that would result from decreases in emissions. An observation-constrained method is applied to infer the dependence of Earth's climate sensitivity on forcing by anthropogenic aerosols within the uncertainty on that forcing given by the Fifth (2013) Assessment Report of the Intergovernmental Panel on Climate Change. Within these uncertainty ranges the increase in GMST due to temperature lag for future forcings held constant is slight (0.09–0.19 K over 20 years; 0.12–0.26 K over 100 years). However the incremental increase in GMST that would result from a hypothetical abrupt cessation of sources of aerosols could be quite large, but is highly uncertain, 0.1–1.3 K over 20 years. Decrease in CO2 abundance and forcing following abrupt cessation of emissions would offset these increases in GMST over 100 years by as little as 0.09 K to as much as 0.8 K. The uncertainties quantified here greatly limit confidence in projections of change in GMST that would result from any strategy for future reduction of emissions.

Authors:
ORCiD logo [1]
  1. Brookhaven National Lab. (BNL), Upton, NY (United States)
Publication Date:
Research Org.:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Org.:
USDOE Office of Science (SC), Biological and Environmental Research (BER) (SC-23)
OSTI Identifier:
1426441
Alternate Identifier(s):
OSTI ID: 1432909
Report Number(s):
BNL-203354-2018-JAAM
Journal ID: ISSN 2169-897X
Grant/Contract Number:  
SC0012704; DE‐SC0012704
Resource Type:
Accepted Manuscript
Journal Name:
Journal of Geophysical Research: Atmospheres
Additional Journal Information:
Journal Volume: 123; Journal Issue: 7; Journal ID: ISSN 2169-897X
Publisher:
American Geophysical Union
Country of Publication:
United States
Language:
English
Subject:
54 ENVIRONMENTAL SCIENCES

Citation Formats

Schwartz, Stephen E. Unrealized Global Temperature Increase: Implications of Current Uncertainties. United States: N. p., 2018. Web. doi:10.1002/2017JD028121.
Schwartz, Stephen E. Unrealized Global Temperature Increase: Implications of Current Uncertainties. United States. doi:10.1002/2017JD028121.
Schwartz, Stephen E. Wed . "Unrealized Global Temperature Increase: Implications of Current Uncertainties". United States. doi:10.1002/2017JD028121. https://www.osti.gov/servlets/purl/1426441.
@article{osti_1426441,
title = {Unrealized Global Temperature Increase: Implications of Current Uncertainties},
author = {Schwartz, Stephen E.},
abstractNote = {Unrealized increase in global mean surface air temperature (GMST) may result from the climate system not being in steady state with forcings and/or from cessation of negative aerosol forcing that would result from decreases in emissions. An observation-constrained method is applied to infer the dependence of Earth's climate sensitivity on forcing by anthropogenic aerosols within the uncertainty on that forcing given by the Fifth (2013) Assessment Report of the Intergovernmental Panel on Climate Change. Within these uncertainty ranges the increase in GMST due to temperature lag for future forcings held constant is slight (0.09–0.19 K over 20 years; 0.12–0.26 K over 100 years). However the incremental increase in GMST that would result from a hypothetical abrupt cessation of sources of aerosols could be quite large, but is highly uncertain, 0.1–1.3 K over 20 years. Decrease in CO2 abundance and forcing following abrupt cessation of emissions would offset these increases in GMST over 100 years by as little as 0.09 K to as much as 0.8 K. The uncertainties quantified here greatly limit confidence in projections of change in GMST that would result from any strategy for future reduction of emissions.},
doi = {10.1002/2017JD028121},
journal = {Journal of Geophysical Research: Atmospheres},
number = 7,
volume = 123,
place = {United States},
year = {2018},
month = {3}
}

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