The challenge of simulating the warmth of the mid-Miocene climatic optimum in CESM1
The mid-Miocene climatic optimum (MMCO) is an intriguing climatic period due to its above-modern temperatures in mid-to-high latitudes in the presence of close-to-modern CO 2 concentrations. We use the recently released Community Earth System Model (CESM1.0) with a slab ocean to simulate this warm p...
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ftdoajarticles:oai:doaj.org/article:293f8dd82dbc43e3ac98ec9b9c329560 2023-05-15T13:52:13+02:00 The challenge of simulating the warmth of the mid-Miocene climatic optimum in CESM1 A. Goldner N. Herold M. Huber 2014-03-01T00:00:00Z https://doi.org/10.5194/cp-10-523-2014 https://doaj.org/article/293f8dd82dbc43e3ac98ec9b9c329560 EN eng Copernicus Publications http://www.clim-past.net/10/523/2014/cp-10-523-2014.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 1814-9324 1814-9332 doi:10.5194/cp-10-523-2014 https://doaj.org/article/293f8dd82dbc43e3ac98ec9b9c329560 Climate of the Past, Vol 10, Iss 2, Pp 523-536 (2014) Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 article 2014 ftdoajarticles https://doi.org/10.5194/cp-10-523-2014 2022-12-31T02:44:54Z The mid-Miocene climatic optimum (MMCO) is an intriguing climatic period due to its above-modern temperatures in mid-to-high latitudes in the presence of close-to-modern CO 2 concentrations. We use the recently released Community Earth System Model (CESM1.0) with a slab ocean to simulate this warm period, incorporating recent Miocene CO 2 reconstructions of 400 ppm (parts per million). We simulate a global mean annual temperature (MAT) of 18 °C, ~4 °C above the preindustrial value, but 4 °C colder than the global Miocene MAT we calculate from climate proxies. Sensitivity tests reveal that the inclusion of a reduced Antarctic ice sheet, an equatorial Pacific temperature gradient characteristic of a permanent El Niño, increased CO 2 to 560 ppm, and variations in obliquity only marginally improve model–data agreement. All MMCO simulations have an Equator to pole temperature gradient that is at least ~10 °C larger than that reconstructed from proxies. The MMCO simulation most comparable to the proxy records requires a CO 2 concentration of 800 ppm. Our results illustrate that MMCO warmth is not reproducible using the CESM1.0 forced with CO 2 concentrations reconstructed for the Miocene or including various proposed Earth system feedbacks; the remaining discrepancy in the MAT is comparable to that introduced by a CO 2 doubling. The model's tendency to underestimate proxy derived global MAT and overestimate the Equator to pole temperature gradient suggests a major climate problem in the MMCO akin to those in the Eocene. Our results imply that this latest model, as with previous generations of climate models, is either not sensitive enough or additional forcings remain missing that explain half of the anomalous warmth and pronounced polar amplification of the MMCO. Article in Journal/Newspaper Antarc* Antarctic Ice Sheet Directory of Open Access Journals: DOAJ Articles Antarctic Pacific Climate of the Past 10 2 523 536 |
institution |
Open Polar |
collection |
Directory of Open Access Journals: DOAJ Articles |
op_collection_id |
ftdoajarticles |
language |
English |
topic |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
spellingShingle |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 A. Goldner N. Herold M. Huber The challenge of simulating the warmth of the mid-Miocene climatic optimum in CESM1 |
topic_facet |
Environmental pollution TD172-193.5 Environmental protection TD169-171.8 Environmental sciences GE1-350 |
description |
The mid-Miocene climatic optimum (MMCO) is an intriguing climatic period due to its above-modern temperatures in mid-to-high latitudes in the presence of close-to-modern CO 2 concentrations. We use the recently released Community Earth System Model (CESM1.0) with a slab ocean to simulate this warm period, incorporating recent Miocene CO 2 reconstructions of 400 ppm (parts per million). We simulate a global mean annual temperature (MAT) of 18 °C, ~4 °C above the preindustrial value, but 4 °C colder than the global Miocene MAT we calculate from climate proxies. Sensitivity tests reveal that the inclusion of a reduced Antarctic ice sheet, an equatorial Pacific temperature gradient characteristic of a permanent El Niño, increased CO 2 to 560 ppm, and variations in obliquity only marginally improve model–data agreement. All MMCO simulations have an Equator to pole temperature gradient that is at least ~10 °C larger than that reconstructed from proxies. The MMCO simulation most comparable to the proxy records requires a CO 2 concentration of 800 ppm. Our results illustrate that MMCO warmth is not reproducible using the CESM1.0 forced with CO 2 concentrations reconstructed for the Miocene or including various proposed Earth system feedbacks; the remaining discrepancy in the MAT is comparable to that introduced by a CO 2 doubling. The model's tendency to underestimate proxy derived global MAT and overestimate the Equator to pole temperature gradient suggests a major climate problem in the MMCO akin to those in the Eocene. Our results imply that this latest model, as with previous generations of climate models, is either not sensitive enough or additional forcings remain missing that explain half of the anomalous warmth and pronounced polar amplification of the MMCO. |
format |
Article in Journal/Newspaper |
author |
A. Goldner N. Herold M. Huber |
author_facet |
A. Goldner N. Herold M. Huber |
author_sort |
A. Goldner |
title |
The challenge of simulating the warmth of the mid-Miocene climatic optimum in CESM1 |
title_short |
The challenge of simulating the warmth of the mid-Miocene climatic optimum in CESM1 |
title_full |
The challenge of simulating the warmth of the mid-Miocene climatic optimum in CESM1 |
title_fullStr |
The challenge of simulating the warmth of the mid-Miocene climatic optimum in CESM1 |
title_full_unstemmed |
The challenge of simulating the warmth of the mid-Miocene climatic optimum in CESM1 |
title_sort |
challenge of simulating the warmth of the mid-miocene climatic optimum in cesm1 |
publisher |
Copernicus Publications |
publishDate |
2014 |
url |
https://doi.org/10.5194/cp-10-523-2014 https://doaj.org/article/293f8dd82dbc43e3ac98ec9b9c329560 |
geographic |
Antarctic Pacific |
geographic_facet |
Antarctic Pacific |
genre |
Antarc* Antarctic Ice Sheet |
genre_facet |
Antarc* Antarctic Ice Sheet |
op_source |
Climate of the Past, Vol 10, Iss 2, Pp 523-536 (2014) |
op_relation |
http://www.clim-past.net/10/523/2014/cp-10-523-2014.pdf https://doaj.org/toc/1814-9324 https://doaj.org/toc/1814-9332 1814-9324 1814-9332 doi:10.5194/cp-10-523-2014 https://doaj.org/article/293f8dd82dbc43e3ac98ec9b9c329560 |
op_doi |
https://doi.org/10.5194/cp-10-523-2014 |
container_title |
Climate of the Past |
container_volume |
10 |
container_issue |
2 |
container_start_page |
523 |
op_container_end_page |
536 |
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