TY - JOUR
T1 - Global mean surface temperature and climate sensitivity of the early Eocene Climatic Optimum (EECO), Paleocene-Eocene Thermal Maximum (PETM), and latest Paleocene
AU - Inglis, Gordon N.
AU - Bragg, Fran
AU - Burls, Natalie J.
AU - Cramwinckel, Margot J.
AU - Evans, David
AU - Foster, Gavin L.
AU - Huber, Matthew
AU - Lunt, Daniel J.
AU - Siler, Nicholas
AU - Steinig, Sebastian
AU - Tierney, Jessica E.
AU - Wilkinson, Richard
AU - Anagnostou, Eleni
AU - M. De Boer, Agatha
AU - Dunkley Jones, Tom
AU - Edgar, Kirsty M.
AU - Hollis, Christopher J.
AU - Hutchinson, David K.
AU - Pancost, Richard D.
N1 - Publisher Copyright:
© 2020 American Institute of Physics Inc.. All rights reserved.
PY - 2020/10/26
Y1 - 2020/10/26
N2 - Accurate estimates of past global mean surface temperature (GMST) help to contextualise future climate change and are required to estimate the sensitivity of the climate system to CO2 forcing through Earth s history. Previous GMST estimates for the latest Paleocene and early Eocene (57 to 48 million years ago) span a wide range (9 to 23 C higher than pre-industrial) and prevent an accurate assessment of climate sensitivity during this extreme greenhouse climate interval. Using the most recent data compilations, we employ a multi-method experimental framework to calculate GMST during the three DeepMIP target intervals: (1) the latest Paleocene (57 Ma), (2) the Paleocene Eocene Thermal Maximum (PETM; 56 Ma), and (3) the early Eocene Climatic Optimum (EECO; 53.3 to 49.1 Ma). Using six different methodologies, we find that the average GMST estimate (66% confidence) during the latest Paleocene, PETM, and EECO was 26.3 C (22.3 to 28.3 C), 31.6 C (27.2 to 34.5 C), and 27.0 C (23.2 to 29.7 C), respectively. GMST estimates from the EECO are 10 to 16 C warmer than pre-industrial, higher than the estimate given by the Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report (9 to 14 C higher than pre-industrial). Leveraging the large "signal" associated with these extreme warm climates, we combine estimates of GMST and CO2 from the latest Paleocene, PETM, and EECO to calculate gross estimates of the average climate sensitivity between the early Paleogene and today. We demonstrate that "bulk" equilibrium climate sensitivity (ECS; 66% confidence) during the latest Paleocene, PETM, and EECO is 4.5 C (2.4 to 6.8 C), 3.6 C (2.3 to 4.7 C), and 3.1 C (1.8 to 4.4 C) per doubling of CO2. These values are generally similar to those assessed by the IPCC (1.5 to 4.5 C per doubling CO2) but appear incompatible with low ECS values (1:5 per doubling CO2).
AB - Accurate estimates of past global mean surface temperature (GMST) help to contextualise future climate change and are required to estimate the sensitivity of the climate system to CO2 forcing through Earth s history. Previous GMST estimates for the latest Paleocene and early Eocene (57 to 48 million years ago) span a wide range (9 to 23 C higher than pre-industrial) and prevent an accurate assessment of climate sensitivity during this extreme greenhouse climate interval. Using the most recent data compilations, we employ a multi-method experimental framework to calculate GMST during the three DeepMIP target intervals: (1) the latest Paleocene (57 Ma), (2) the Paleocene Eocene Thermal Maximum (PETM; 56 Ma), and (3) the early Eocene Climatic Optimum (EECO; 53.3 to 49.1 Ma). Using six different methodologies, we find that the average GMST estimate (66% confidence) during the latest Paleocene, PETM, and EECO was 26.3 C (22.3 to 28.3 C), 31.6 C (27.2 to 34.5 C), and 27.0 C (23.2 to 29.7 C), respectively. GMST estimates from the EECO are 10 to 16 C warmer than pre-industrial, higher than the estimate given by the Intergovernmental Panel on Climate Change (IPCC) 5th Assessment Report (9 to 14 C higher than pre-industrial). Leveraging the large "signal" associated with these extreme warm climates, we combine estimates of GMST and CO2 from the latest Paleocene, PETM, and EECO to calculate gross estimates of the average climate sensitivity between the early Paleogene and today. We demonstrate that "bulk" equilibrium climate sensitivity (ECS; 66% confidence) during the latest Paleocene, PETM, and EECO is 4.5 C (2.4 to 6.8 C), 3.6 C (2.3 to 4.7 C), and 3.1 C (1.8 to 4.4 C) per doubling of CO2. These values are generally similar to those assessed by the IPCC (1.5 to 4.5 C per doubling CO2) but appear incompatible with low ECS values (1:5 per doubling CO2).
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U2 - 10.5194/cp-16-1953-2020
DO - 10.5194/cp-16-1953-2020
M3 - Article
AN - SCOPUS:85094842119
SN - 1814-9324
VL - 16
SP - 1953
EP - 1968
JO - Climate of the Past
JF - Climate of the Past
IS - 5
M1 - 1953
ER -