Featured Research

from universities, journals, and other organizations

Earth’s sensitivity to climate change could be 'double' previous estimates, say geologists

Date:
December 10, 2013
Source:
Geological Society of London, The
Summary:
The sensitivity of Earth’s climate to carbon dioxide could be double what has been previously estimated, according to geologists.

The sensitivity of Earth's climate to CO2 could be double what has been previously estimated, according to a statement issued by the Geological Society of London.

In an addendum to 2010's 'Climate change: Evidence from the Geological Record', the statement notes that many climate models typically look at short term, rapid factors when calculating Earth's climate sensitivity -- defined as the mean global temperature increase brought about by a doubling of atmospheric CO2.

It is well known that a doubling of atmospheric CO2 levels could result in temperature increases of between 1.5 and 4.5C, due to fast changes such as snow and ice melt, and the behavior of clouds and water vapor.

Geological evidence from studies of past climate change now suggests that if longer term factors are taken into account, such as the decay of large ice sheets and the operation of the full carbon cycle, the sensitivity of Earth to a doubling of CO2 could be double that predicted by most climate models.

Dr Colin Summerhayes, who led the statement's working group, says 'Geological studies of past climate change are throwing new light on how Earth may respond to growing emissions of CO2. The climate sensitivity suggested by modern climate models may be fine for the short term, but does not encompass the full range of change expected in the long term as Earth's climate moves slowly towards equilibrium.'

The statement also highlights new data showing that temperature and CO2 levels recorded in Antarctic ice cores increase at the same time. This, says Summerhayes, 'makes the role of CO2 in changing Ice Age climate highly significant.'

Atmospheric carbon levels are current at just below 400 parts per million -- a figure last seen during the Pliocene, between 5.3 and 2.6 million years ago. At that time, global temperatures were 2-3C higher than today, and sea levels were several meters higher, due to partial melting of the Antarctic ice sheet.

If the current rate of increase (2 ppm per year) continues, CO2 levels could reach 600 ppm by the end of this century; levels which, says Summerhayes, 'have not been seen for 24 million years.'

The statement outlines evidence that a relatively modest rise in atmospheric CO2 levels and temperature results in significant sea level rise, while oceans become more acidic and less oxygenated. Previous such events, such as the Paleocene-Eocene Thermal Maximum (PETM) 55 million years ago, caused marine crises and extinctions, with Earth System taking around 100,000 years to recover.

'We now have even more confidence from the geological record' says Summerhayes, 'that the only plausible explanation for current warming is the unprecedented exponential rise in CO2 and other greenhouse gases. Recent compilations of past climate data, along with astronomical calculations, show that changes in Earth's orbit and axis cooled the world over the past 10,000 years. This cooling would normally be expected to continue for at least another 1,000 years.

'And yet Arctic palaeoclimate records show that the period 1950-2000 was the warmest 50 year interval for 2,000 years. We should be cool, but we're not.'

The statement can be accessed at: http://www.geolsoc.org.uk/climatechange


Story Source:

The above story is based on materials provided by Geological Society of London, The. Note: Materials may be edited for content and length.


Cite This Page:

Geological Society of London, The. "Earth’s sensitivity to climate change could be 'double' previous estimates, say geologists." ScienceDaily. ScienceDaily, 10 December 2013. <www.sciencedaily.com/releases/2013/12/131210072028.htm>.
Geological Society of London, The. (2013, December 10). Earth’s sensitivity to climate change could be 'double' previous estimates, say geologists. ScienceDaily. Retrieved April 16, 2014 from www.sciencedaily.com/releases/2013/12/131210072028.htm
Geological Society of London, The. "Earth’s sensitivity to climate change could be 'double' previous estimates, say geologists." ScienceDaily. www.sciencedaily.com/releases/2013/12/131210072028.htm (accessed April 16, 2014).

Share This



More Earth & Climate News

Wednesday, April 16, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Change of Diet Helps Crocodile Business

Change of Diet Helps Crocodile Business

Reuters - Business Video Online (Apr. 16, 2014) Crocodile farming has been a challenge in Zimbabwe in recent years do the economic collapse and the financial crisis. But as Ciara Sutton reports one of Europe's biggest suppliers of skins to the luxury market has come up with an unusual survival strategy - vegetarian food. Video provided by Reuters
Powered by NewsLook.com
How Mt. Everest Helped Scientists Research Diabetes

How Mt. Everest Helped Scientists Research Diabetes

Newsy (Apr. 15, 2014) British researchers were able to use Mount Everest's low altitudes to study insulin resistance. They hope to find ways to treat diabetes. Video provided by Newsy
Powered by NewsLook.com
The Walking, Talking Oil-Drigging Rig

The Walking, Talking Oil-Drigging Rig

Reuters - Business Video Online (Apr. 15, 2014) Pennsylvania-based Schramm is incorporating modern technology in its next generation oil-drigging rigs, making them smaller, safer and smarter. Ernest Scheyder reports. Video provided by Reuters
Powered by NewsLook.com
In Washington, a Push to Sterilize Stray Cats

In Washington, a Push to Sterilize Stray Cats

AFP (Apr. 14, 2014) To curb the growing numbers of feral cats in the US capital, the Washington Humane Society is encouraging residents to set traps and bring the animals to a sterilization clinic, after which they are released.. Duration: 02:29 Video provided by AFP
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