Earth system commitments due to delayed mitigation

Pfister, Patrik L; Stocker, Thomas F (2016). Earth system commitments due to delayed mitigation. Environmental Research Letters, 11(1), 014010. IOP Publishing 10.1088/1748-9326/11/1/014010

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As long as global CO₂ emissions continue to increase annually, long-term committed Earth system changes grow much faster than current observations. A novel metric linking this future growth to policy decisions today is the mitigation delay sensitivity (MDS), but MDS estimates for Earth system variables other than peak temperature (ΔT max) are missing. Using an Earth System Model of Intermediate Complexity, we show that the current emission increase rate causes a ΔT max increase roughly 3–7.5 times as fast as observed warming, and a millenial steric sea level rise (SSLR) 7–25 times as fast as observed SSLR, depending on the achievable rate of emission reductions after the peak of emissions. These ranges are only slightly affected by the uncertainty range in equilibrium climate sensitivity, which is included in the above values. The extent of ocean acidification at the end of the century is also strongly dependent on the starting time and rate of emission reductions. The preservable surface ocean area with sufficient aragonite supersaturation for coral reef growth is diminished globally at an MDS of roughly 25%–80% per decade. A near-complete loss of this area becomes unavoidable if mitigation is delayed for a few years to decades. Also with respect to aragonite, 12%–18% of the Southern Ocean surface become undersaturated per decade, if emission reductions are delayed beyond 2015–2040. We conclude that the consequences of delaying global emission reductions are much better captured if the MDS of relevant Earth system variables is communicated in addition to current trends and total projected future changes.

Item Type:

Journal Article (Further Contribution)

Division/Institute:

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

UniBE Contributor:

Pfister, Patrik and Stocker, Thomas

Subjects:

500 Science > 530 Physics

ISSN:

1748-9326

Publisher:

IOP Publishing

Language:

English

Submitter:

Doris Rätz

Date Deposited:

25 Feb 2016 09:02

Last Modified:

25 Feb 2016 09:02

Publisher DOI:

10.1088/1748-9326/11/1/014010

BORIS DOI:

10.7892/boris.75981

URI:

https://boris.unibe.ch/id/eprint/75981

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