Nonlinear climatic sensitivity to greenhouse gases over past 4 glacial/interglacial cycles

Li Lo; Sheng-Pu Chang; Kuo-Yen Wei; Shih-Yu Lee; Tsong-Hua Ou; Yi-Chi Chen; Chih-Kai Chuang; Horng-Sheng Mii; George S Burr; Min-Te Chen; Ying-Hung Tung; Meng-Chieh Tsai; David A Hodell; Chuan-Chou Shen

doi:10.1038/s41598-017-04031-x

Nonlinear climatic sensitivity to greenhouse gases over past 4 glacial/interglacial cycles

Sci Rep. 2017 Jul 4;7(1):4626. doi: 10.1038/s41598-017-04031-x.

Authors

Li Lo^{1

2

3}, Sheng-Pu Chang⁴, Kuo-Yen Wei⁴, Shih-Yu Lee⁵, Tsong-Hua Ou⁶, Yi-Chi Chen⁴, Chih-Kai Chuang⁴, Horng-Sheng Mii⁷, George S Burr⁸, Min-Te Chen⁹, Ying-Hung Tung⁴, Meng-Chieh Tsai⁴, David A Hodell¹⁰, Chuan-Chou Shen¹¹

Affiliations

¹ High-Precision Mass Spectrometry and Environment Change Laboratory (HISPEC), Department of Geosciences, National Taiwan University, Taipei, 10617, Taiwan, ROC. lilo@gig.ac.cn.
² Department of Earth Sciences, University of Cambridge, Cambridge, Cambridgeshire, CB2 3EQ, UK. lilo@gig.ac.cn.
³ State Key Laboratory of Isotope Geochemistry, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou, 510640, People's Republic of China. lilo@gig.ac.cn.
⁴ High-Precision Mass Spectrometry and Environment Change Laboratory (HISPEC), Department of Geosciences, National Taiwan University, Taipei, 10617, Taiwan, ROC.
⁵ Research Center for Environmental Changes, Academia Sinica, Taipei, 11529, Taiwan, ROC. shihyu@gate.sinica.edu.tw.
⁶ Institute of Applied Mechanics, National Taiwan University, Taipei, 10617, Taiwan, ROC.
⁷ Department of Earth Sciences, National Taiwan Normal University, Taipei, 11677, Taiwan, ROC.
⁸ NSF-Arizona Accelerator Mass Spectrometry Laboratory, University of Arizona, Tucson, AZ, 85721, USA.
⁹ Institute of Applied Geosciences, National Taiwan Ocean University, Keelung, 20224, Taiwan, ROC.
¹⁰ Department of Earth Sciences, University of Cambridge, Cambridge, Cambridgeshire, CB2 3EQ, UK.
¹¹ High-Precision Mass Spectrometry and Environment Change Laboratory (HISPEC), Department of Geosciences, National Taiwan University, Taipei, 10617, Taiwan, ROC. river@ntu.edu.tw.

Abstract

The paleoclimatic sensitivity to atmospheric greenhouse gases (GHGs) has recently been suggested to be nonlinear, however a GHG threshold value associated with deglaciation remains uncertain. Here, we combine a new sea surface temperature record spanning the last 360,000 years from the southern Western Pacific Warm Pool with records from five previous studies in the equatorial Pacific to document the nonlinear relationship between climatic sensitivity and GHG levels over the past four glacial/interglacial cycles. The sensitivity of the responses to GHG concentrations rises dramatically by a factor of 2-4 at atmospheric CO₂ levels of >220 ppm. Our results suggest that the equatorial Pacific acts as a nonlinear amplifier that allows global climate to transition from deglacial to full interglacial conditions once atmospheric CO₂ levels reach threshold levels.

Publication types

Research Support, Non-U.S. Gov't