Scientists develop new approach to support future climate projections

Nov 28, 2012

Scientists have developed a new approach for evaluating past climate sensitivity data to help improve comparison with estimates of long-term climate projections developed by the Intergovernmental Panel on Climate Change (IPCC).

The sensitivity of to changes in the Earth's (climate sensitivity) is a key factor for understanding past natural climate changes as well as potential future climate change.

Many palaeoclimate studies have measured natural climate changes to calculate climate sensitivity, but a lack of consistent methodologies produced a wide range of as to the exact value of climate sensitivity, which hindered results.

Now a team of international scientists including Eelco Rohling, Professor of Ocean and Climate Change at the University of Southampton, have developed a more consistent definition of climate sensitivity in . When the scientists evaluated previously published estimates for climate sensitivity from a variety of geological episodes over the past , they found that the estimates varied over a very wide range of values, with some very high values among them (high values would imply a very strong temperature response to a change in radiative forcing, for example, due to CO2 increase).

The team discovered that this wide range was almost entirely due to the fact that different researchers used different definitions.

Professor Rohling, who is currently based at the National Oceanography Centre Southampton but will join the Australian National University next year, says: "Consistent intercomparison is a top priority, because it is central to using past climate sensitivity estimates in assessing the of future climate projections.

"Once we had developed the framework and we had elaborated all the different assumptions and uncertainties, we applied it to climate reconstruction data from the last 65 million years. This caused a much narrower range of estimates, and this range was now defined in such a way that we could directly compare it with estimates in the IPCC assessment for their longer-term (several centuries) outlook."

The scientists found that the likely range of climate sensitivity consistently has been of the order of 2.2 to 4.8 degrees C per doubling of CO2, which closely agrees with the IPCC estimates.

Professor Rohling adds: "Our study only documents what the has been over the last 65 million years, and how realistic the estimates of the IPCC are in that context. It finds that those estimates are fully coherent with what nature has done in the (natural) past before human-based effects. Hence, it strongly endorses the IPCC's long-term climate projections based on such values: nature shows us it always has, and so likely will again, respond in a way close to what the models suggest, as far as warming is concerned."

The findings are published in the latest edition of the journal Nature.

Explore further: US delays decision on Keystone pipeline project

Related Stories

Explained: Climate sensitivity

Mar 19, 2010

Climate sensitivity is the term used by the Intergovernmental Panel on Climate Change (IPCC) to express the relationship between the human-caused emissions that add to the Earth's greenhouse effect -- carbon ...

55 million years of climate change

Jun 27, 2011

State-of-the-art climate models, as used in the assessments of the Intergovernmental Panel for Climate Change, could be giving a false sense of security in terms of upcoming abrupt change, suggests a Commentary ...

2C warming goal now 'optimistic' - French scientists

Feb 09, 2012

French scientists unveiling new estimates for global warming said on Thursday the 2 C (3.6 F) goal enshrined by the United Nations was "the most optimistic" scenario left for greenhouse-gas emissions.

Models look good when predicting climate change

Apr 02, 2008

The accuracy of computer models that predict climate change over the coming decades has been the subject of debate among politicians, environmentalists and even scientists. A new study by meteorologists at the University ...

Recommended for you

US delays decision on Keystone pipeline project

Apr 18, 2014

The United States announced Friday a fresh delay on a final decision regarding a controversial Canada to US oil pipeline, saying more time was needed to carry out a review.

New research on Earth's carbon budget

Apr 18, 2014

(Phys.org) —Results from a research project involving scientists from the Desert Research Institute have generated new findings surrounding some of the unknowns of changes in climate and the degree to which ...

User comments : 0

More news stories

China says massive area of its soil polluted

A huge area of China's soil covering more than twice the size of Spain is estimated to be polluted, the government said Thursday, announcing findings of a survey previously kept secret.

UN weather agency warns of 'El Nino' this year

The UN weather agency Tuesday warned there was a good chance of an "El Nino" climate phenomenon in the Pacific Ocean this year, bringing droughts and heavy rainfall to the rest of the world.

UAE reports 12 new cases of MERS

Health authorities in the United Arab Emirates have announced 12 new cases of infection by the MERS coronavirus, but insisted the patients would be cured within two weeks.