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Late Pleistocene tropical Pacific temperature sensitivity to radiative greenhouse gas forcing

Kelsey A. Dyez and A. Christina Ravelo
Late Pleistocene tropical Pacific temperature sensitivity to radiative greenhouse gas forcing
Geology (Boulder) (October 2012) 41 (1): 23-26

Abstract

Understanding how global temperature changes with increasing atmospheric greenhouse gas concentrations, or climate sensitivity, is of central importance to climate change research. Climate models provide sensitivity estimates that may not fully incorporate slow, long-term feedbacks such as those involving ice sheets and vegetation. Geological studies, on the other hand, can provide estimates that integrate long- and short-term climate feedbacks to radiative forcing. Because high latitudes are thought to be most sensitive to greenhouse gas forcing owing to, for example, ice-albedo feedbacks, we focus on the tropical Pacific Ocean to derive a minimum value for long-term climate sensitivity. Using Mg/Ca paleothermometry from the planktonic foraminifera Globigerinoides ruber from the past 500 k.y. at Ocean Drilling Program (ODP) Site 871 in the western Pacific warm pool, we estimate the tropical Pacific climate sensitivity parameter (lambda ) to be 0.94-1.06 degrees C (W m (super -2) ) (super -1) , higher than that predicted by model simulations of the Last Glacial Maximum or by models of doubled greenhouse gas concentration forcing. This result suggests that models may not yet adequately represent the long-term feedbacks related to ocean circulation, vegetation and associated dust, or the cryosphere, and/or may underestimate the effects of tropical clouds or other short-term feedback processes.


ISSN: 0091-7613
EISSN: 1943-2682
Coden: GLGYBA
Serial Title: Geology (Boulder)
Serial Volume: 41
Serial Issue: 1
Title: Late Pleistocene tropical Pacific temperature sensitivity to radiative greenhouse gas forcing
Affiliation: University of California at Santa Cruz, Department of Earth and Planetary Sciences, Santa Cruz, CA, United States
Pages: 23-26
Published: 20121019
Text Language: English
Publisher: Geological Society of America (GSA), Boulder, CO, United States
References: 31
Accession Number: 2012-101389
Categories: Quaternary geologyGeneral geochemistry
Document Type: Serial
Bibliographic Level: Analytic
Annotation: With GSA Data Repository Item 2013008
Illustration Description: illus. incl. sketch map
N05°33'26" - N05°33'26", E172°20'40" - E172°20'40"
Country of Publication: United States
Secondary Affiliation: GeoRef, Copyright 2017, American Geosciences Institute. Reference includes data from GeoScienceWorld, Alexandria, VA, United States. Reference includes data supplied by the Geological Society of America, Boulder, CO, United States
Update Code: 201252
Program Name: ODPOcean Drilling Program
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