Featured Research

from universities, journals, and other organizations

Close Relationship Between Past Warming And Sea-level Rise

Date:
July 7, 2009
Source:
National Oceanography Centre, Southampton (UK)
Summary:
Scientists have reconstructed sea-level fluctuations over the last 520,000 years. Comparison of this record with data on global climate and CO2 levels from Antarctic ice cores suggests that even stabilization at today's carbon dioxide levels may commit us to much greater sea-level rise over the next couple of millennia than previously thought.

Example projections of 0-7 m (yellow), 7-15 m (orange), 15-25 m (red) flooding, based on http://freegeographytools.com/2007/sea-level-rise-google-mapplet
Credit: Image courtesy of National Oceanography Centre, Southampton (UK)

A team from the National Oceanography Centre, Southampton (NOCS), along with colleagues from Tübingen (Germany) and Bristol presents a novel continuous reconstruction of sea level fluctuations over the last 520 thousand years. Comparison of this record with data on global climate and carbon dioxide (CO2) levels from Antarctic ice cores suggests that even stabilisation at today's CO2 levels may commit us to sea-level rise over the next couple of millennia, to a level much higher than long-term projections from the Fourth Assessment Report of the Intergovernmental Panel on Climate Change (IPCC).

Little is known about the total amount of possible sea-level rise in equilibrium with a given amount of global warming. This is because the melting of ice sheets is slow, even when temperature rises rapidly. As a consequence, current predictions of sea-level rise for the next century consider only the amount of ice sheet melt that will occur until that time. The total amount of ice sheet melting that will occur over millennia, given the current climate trends, remains poorly understood.

The new record reveals a systematic equilibrium relationship between global temperature and CO2 concentrations and sea-level changes over the last five glacial cycles. Projection of this relationship to today's CO2 concentrations results in a sea-level at 25 (±5) metres above the present. This is in close agreement with independent sea-level data from the Middle Pliocene epoch, 3-3.5 million years ago, when atmospheric CO2 concentrations were similar to the present-day value. This suggests that the identified relationship accurately records the fundamental long-term equilibrium behaviour of the climate system over the last 3.5 Million years.

Lead author Professor Eelco Rohling of the University of Southampton's School of Ocean and Earth Science based at NOCS, said: "Let's assume that our observed natural relationship between CO2 and temperature, and sea level, offers a reasonable 'model' for a future with sustained global warming. Then our result gives a statistically sound expectation of a potential total long-term sea-level rise. Even if we would curb all CO2 emissions today, and stabilise at the modern level (387 parts per million by volume), then our natural relationship suggests that sea level would continue to rise to about 25 m above the present. That is, it would rise to a level similar to that measured for the Middle Pliocene."

Project partners Professor Michal Kucera (University of Tübingen) and Dr Mark Siddall (University of Bristol), add: "We emphasise that such equilibration of sea level would take several thousands of years. But one still has to worry about the large difference between the inferred high equilibrium sea level and the level where sea level actually stands today. Recent geological history shows that times with similarly strong disequilibria commonly saw pulses of very rapid sea-level adjustment, at rates of 1-2 metres per century or higher."

The new study's projection of long-term sea-level change, based on the natural relationship of the last 0.5 to 3.5 million years, differs considerably from the IPCC's model-based long-term projection of +7 m. The discrepancy cannot be easily explained, and new work is needed to ensure that the 'gap is closed'.

The observed relationships from the recent geological past can form a test-bed or reality-check for models, to help them achieve improved future projections.

The project was funded by the Natural Environment Research Council (UK) and the Deutsche Forschungs-Gemeinschaft (Germany).

The authors are Eelco Rohling (NOCS), Katharine Grant (NOCS), Mike Bolshaw (NOCS), Andrew Roberts (NOCS), Mark Siddall (University of Bristol), Christoph Hemleben (University of Tübingen) and Michal Kucera (University of Tübingen).

.


Story Source:

The above story is based on materials provided by National Oceanography Centre, Southampton (UK). Note: Materials may be edited for content and length.


Journal Reference:

  1. Rohling et al. Antarctic temperature and global sea level closely coupled over the past five glacial cycles. Nature Geoscience, June 21, 2009; DOI: 10.1038/ngeo557

Cite This Page:

National Oceanography Centre, Southampton (UK). "Close Relationship Between Past Warming And Sea-level Rise." ScienceDaily. ScienceDaily, 7 July 2009. <www.sciencedaily.com/releases/2009/06/090622103833.htm>.
National Oceanography Centre, Southampton (UK). (2009, July 7). Close Relationship Between Past Warming And Sea-level Rise. ScienceDaily. Retrieved September 16, 2014 from www.sciencedaily.com/releases/2009/06/090622103833.htm
National Oceanography Centre, Southampton (UK). "Close Relationship Between Past Warming And Sea-level Rise." ScienceDaily. www.sciencedaily.com/releases/2009/06/090622103833.htm (accessed September 16, 2014).

Share This



More Earth & Climate News

Tuesday, September 16, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Conservationists Face Uphill PR Battle With New Shark Rules

Conservationists Face Uphill PR Battle With New Shark Rules

Newsy (Sep. 14, 2014) — New conservation measures for shark fishing face an uphill PR battle in the fight to slow shark extinction. Video provided by Newsy
Powered by NewsLook.com
Pakistan's 'killer Mountain' Fails to Draw Tourists After Attack

Pakistan's 'killer Mountain' Fails to Draw Tourists After Attack

AFP (Sep. 12, 2014) — In June 2013, 10 foreign mountaineers and their guide were murdered on Nanga Parbat, an iconic peak that stands at 8,126m tall in northern Pakisan. Duration: 02:34 Video provided by AFP
Powered by NewsLook.com
Solar Storm To Hit This Weekend, Scientists Not Worried

Solar Storm To Hit This Weekend, Scientists Not Worried

Newsy (Sep. 11, 2014) — Two solar flares which erupted in our direction this week will arrive this weekend. The resulting solar storm will be powerful but not dangerous. Video provided by Newsy
Powered by NewsLook.com
The Ozone Layer Is Recovering, But It's Not All Good News

The Ozone Layer Is Recovering, But It's Not All Good News

Newsy (Sep. 11, 2014) — The Ozone layer is recovering thickness! Hooray! But in helping its recovery, we may have also helped put more greenhouse gases out there. Hooray? Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
 
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:  

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

Environment News

Technology News



Save/Print:
Share:  

Free Subscriptions


Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

Get Social & Mobile


Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

Have Feedback?


Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
Mobile iPhone Android Web
Follow Facebook Twitter Google+
Subscribe RSS Feeds Email Newsletters
Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins