Earth’s radiative imbalance from the Last Glacial Maximum to the present

Baggenstos, Daniel; Häberli, Marcel; Schmitt, Jochen; Shackleton, Sarah A.; Birner, Benjamin; Severinghaus, Jeffrey P.; Kellerhals, Thomas; Fischer, Hubertus (2019). Earth’s radiative imbalance from the Last Glacial Maximum to the present. Proceedings of the National Academy of Sciences of the United States of America - PNAS, 116(30), pp. 14881-14886. National Academy of Sciences NAS 10.1073/pnas.1905447116

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The energy imbalance at the top of the atmosphere determines the temporal evolution of the global climate, and vice versa changes in the climate system can alter the planetary energy fluxes. This interplay is fundamental to our understanding of Earth’s heat budget and the climate system. However, even today, the direct measurement of global radiative fluxes is difficult, such that most assessments are based on changes in the total energy content of the climate system. We apply the same approach to estimate the long-term evolution of Earth’s radiative imbalance in the past. New measurements of noble gas-derived mean ocean temperature from the European Project for Ice Coring in Antarctica Dome C ice core covering the last 40,000 y, combined with recent results from the West Antarctic Ice Sheet Divide ice core and the sea-level record, allow us to quantitatively reconstruct the history of the climate system energy budget. The temporal derivative of this quantity must be equal to the planetary radiative imbalance. During the deglaciation, a positive imbalance of typically +0.2 W⋅m⁻² is maintained for ~10,000 y, however, with two distinct peaks that reach up to 0.4 W⋅m⁻² during times of substantially reduced Atlantic Meridional Overturning Circulation. We conclude that these peaks are related to net changes in ocean heat uptake, likely due to rapid changes in North Atlantic deep-water formation and their impact on the global radiative balance, while changes in cloud coverage, albeit uncertain, may also factor into the picture.

Item Type:

Journal Article (Original Article)

Division/Institute:

08 Faculty of Science > Physics Institute > Climate and Environmental Physics
10 Strategic Research Centers > Oeschger Centre for Climate Change Research (OCCR)
08 Faculty of Science > Physics Institute

UniBE Contributor:

Baggenstos, Daniel and Fischer, Hubertus

Subjects:

500 Science > 530 Physics
500 Science > 550 Earth sciences & geology

ISSN:

0027-8424

Publisher:

National Academy of Sciences NAS

Funders:

[UNSPECIFIED] European Research Council (ERC) under the European Union’s Seventh Framework Program FP7: ERC Grant 226172 (ERC Advanced Grant MATRICs)
[UNSPECIFIED] Swiss National Science Foundation

Projects:

[UNSPECIFIED] MATRICs
[UNSPECIFIED] NOTICE
[UNSPECIFIED] iCEP
[UNSPECIFIED] EPICA

Language:

English

Submitter:

Hubertus Fischer

Date Deposited:

31 Jul 2019 14:06

Last Modified:

31 Jul 2019 14:06

Publisher DOI:

10.1073/pnas.1905447116

BORIS DOI:

10.7892/boris.132143

URI:

https://boris.unibe.ch/id/eprint/132143

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