On the Causes of Mid-Pliocene Warmth and Polar Amplification
The mid-Pliocene (approximately 3 to 3.3 Ma ago), is a period of sustained global warmth in comparison to the late Quaternary (0 to approximately 1 Ma ago), and has potential to inform predictions of long-term future climate change. However, given that several processes potentially contributed, rela...
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ftnasantrs:oai:casi.ntrs.nasa.gov:20140001040 2023-05-15T16:40:59+02:00 On the Causes of Mid-Pliocene Warmth and Polar Amplification Dowsett, Harry J. Loptson, Claire A. Haywood, Alan M. Schmidt, Gavin A. Salzmann, Ulrich Lunt, Daniel J. Valdes, Paul J. Unclassified, Unlimited, Publicly available February 2012 application/pdf http://hdl.handle.net/2060/20140001040 unknown Document ID: 20140001040 http://hdl.handle.net/2060/20140001040 Copyright, Distribution as joint owner in the copyright CASI Meteorology and Climatology GSFC-E-DAA-TN8825 Earth and Planetary Science Letters; 321-322; 128-138 2012 ftnasantrs 2019-07-21T00:34:36Z The mid-Pliocene (approximately 3 to 3.3 Ma ago), is a period of sustained global warmth in comparison to the late Quaternary (0 to approximately 1 Ma ago), and has potential to inform predictions of long-term future climate change. However, given that several processes potentially contributed, relatively little is understood about the reasons for the observed warmth, or the associated polar amplification. Here, using a modelling approach and a novel factorisation method, we assess the relative contributions to mid-Pliocene warmth from: elevated CO2, lowered orography, and vegetation and ice sheet changes. The results show that on a global scale, the largest contributor to mid-Pliocene warmth is elevated CO2. However, in terms of polar amplification, changes to ice sheets contribute significantly in the Southern Hemisphere, and orographic changes contribute significantly in the Northern Hemisphere. We also carry out an energy balance analysis which indicates that that on a global scale, surface albedo and atmospheric emmissivity changes dominate over cloud changes. We investigate the sensitivity of our results to uncertainties in the prescribed CO2 and orographic changes, to derive uncertainty ranges for the various contributing processes. Other/Unknown Material Ice Sheet NASA Technical Reports Server (NTRS) |
institution |
Open Polar |
collection |
NASA Technical Reports Server (NTRS) |
op_collection_id |
ftnasantrs |
language |
unknown |
topic |
Meteorology and Climatology |
spellingShingle |
Meteorology and Climatology Dowsett, Harry J. Loptson, Claire A. Haywood, Alan M. Schmidt, Gavin A. Salzmann, Ulrich Lunt, Daniel J. Valdes, Paul J. On the Causes of Mid-Pliocene Warmth and Polar Amplification |
topic_facet |
Meteorology and Climatology |
description |
The mid-Pliocene (approximately 3 to 3.3 Ma ago), is a period of sustained global warmth in comparison to the late Quaternary (0 to approximately 1 Ma ago), and has potential to inform predictions of long-term future climate change. However, given that several processes potentially contributed, relatively little is understood about the reasons for the observed warmth, or the associated polar amplification. Here, using a modelling approach and a novel factorisation method, we assess the relative contributions to mid-Pliocene warmth from: elevated CO2, lowered orography, and vegetation and ice sheet changes. The results show that on a global scale, the largest contributor to mid-Pliocene warmth is elevated CO2. However, in terms of polar amplification, changes to ice sheets contribute significantly in the Southern Hemisphere, and orographic changes contribute significantly in the Northern Hemisphere. We also carry out an energy balance analysis which indicates that that on a global scale, surface albedo and atmospheric emmissivity changes dominate over cloud changes. We investigate the sensitivity of our results to uncertainties in the prescribed CO2 and orographic changes, to derive uncertainty ranges for the various contributing processes. |
format |
Other/Unknown Material |
author |
Dowsett, Harry J. Loptson, Claire A. Haywood, Alan M. Schmidt, Gavin A. Salzmann, Ulrich Lunt, Daniel J. Valdes, Paul J. |
author_facet |
Dowsett, Harry J. Loptson, Claire A. Haywood, Alan M. Schmidt, Gavin A. Salzmann, Ulrich Lunt, Daniel J. Valdes, Paul J. |
author_sort |
Dowsett, Harry J. |
title |
On the Causes of Mid-Pliocene Warmth and Polar Amplification |
title_short |
On the Causes of Mid-Pliocene Warmth and Polar Amplification |
title_full |
On the Causes of Mid-Pliocene Warmth and Polar Amplification |
title_fullStr |
On the Causes of Mid-Pliocene Warmth and Polar Amplification |
title_full_unstemmed |
On the Causes of Mid-Pliocene Warmth and Polar Amplification |
title_sort |
on the causes of mid-pliocene warmth and polar amplification |
publishDate |
2012 |
url |
http://hdl.handle.net/2060/20140001040 |
op_coverage |
Unclassified, Unlimited, Publicly available |
genre |
Ice Sheet |
genre_facet |
Ice Sheet |
op_source |
CASI |
op_relation |
Document ID: 20140001040 http://hdl.handle.net/2060/20140001040 |
op_rights |
Copyright, Distribution as joint owner in the copyright |
_version_ |
1766031412496957440 |