Adaptive-decision strategy offsets uncertainties in climate sensitivity

September 28, 2001

CHAMPAIGN, Ill. -- The uncertainty of climate change because of global warming is much greater than previously thought, and as a result, policy-makers should adopt a robust, adaptive-decision strategy to cope with potential consequences, researchers at the University of Illinois say.

As will be reported in the Oct. 16 issue of the Journal of Geophysical Research, UI atmospheric scientists Natalia Andronova and Michael Schlesinger found there is a 54 percent chance that climate sensitivity lies outside the 1.5 to 4.5 degree Centigrade range announced by the Intergovernmental Panel on Climate Change.

"This is definitely not good news," Schlesinger said. "If the climate sensitivity is greater than the IPCC's upper bound, climate change could be one of humanity's most severe problems of the 21st century. If, however, it is less than the lower bound, then climate change may not be a serious problem for humanity."

In a study supported by the National Science Foundation and the U.S. Department of Energy, the researchers used a simple climate/ocean model and the observed near-surface temperature record to estimate the probability distribution for climate sensitivity. For each of 16 radiative-forcing models, the changes in global-mean near-surface temperature were calculated for the years 1765 through 1997. The radiative-forcing models included greenhouse gases, anthropogenic sulfate aerosol, volcanoes and solar irradiance. The researchers found that, as a result of natural variability and uncertainty in the radiative forcing, it is 90 percent likely that climate sensitivity lies between 1 and 10 degrees Centigrade.

While some scientists have argued that the IPCC should assign subjective probabilities to its various scenarios of future climate change, Schlesinger and colleague Robert Lempert (of the Rand Corp.) disagree. Optimization plans should not be based upon subjective probabilities because "decision-makers must form a climate policy acceptable to groups with many different, yet plausible, estimates of the likelihood of alternative futures," the two researchers wrote in the July 26 issue of the journal Nature.

The large uncertainties associated with the climate-change problem can make conventional policy prescriptions unreliable, Schlesinger said. "It could take a fair fraction of a century to acquire enough observations to significantly reduce the level of uncertainty, and by then it may be too late to do anything about it. By using an adaptive-decision strategy, however, we can observe the damages due to climate change, and the rate of change of the cost differential between fossil fuels and non-fossil fuels. Depending upon what we see, we can alter what we do."

By objectively estimating the likelihood of the climate sensitivity having any particular value - that is, by its probability distribution - the crafting of robust, adaptive climate-change policy could be greatly facilitated, Schlesinger said. "Such a strategy could also aid in the negotiation process, because decision-makers could make more reasonable and defensible choices about climate-change policy without requiring highly accurate or widely accepted predictions of the future."

University of Illinois at Urbana-Champaign

Related Climate Change Articles from Brightsurf:

Are climate scientists being too cautious when linking extreme weather to climate change?
Climate science has focused on avoiding false alarms when linking extreme events to climate change.

Mysterious climate change
New research findings underline the crucial role that sea ice throughout the Southern Ocean played for atmospheric CO2 in times of rapid climate change in the past.

Mapping the path of climate change
Predicting a major transition, such as climate change, is extremely difficult, but the probabilistic framework developed by the authors is the first step in identifying the path between a shift in two environmental states.

Small change for climate change: Time to increase research funding to save the world
A new study shows that there is a huge disproportion in the level of funding for social science research into the greatest challenge in combating global warming -- how to get individuals and societies to overcome ingrained human habits to make the changes necessary to mitigate climate change.

Sub-national 'climate clubs' could offer key to combating climate change
'Climate clubs' offering membership for sub-national states, in addition to just countries, could speed up progress towards a globally harmonized climate change policy, which in turn offers a way to achieve stronger climate policies in all countries.

Review of Chinese atmospheric science research over the past 70 years: Climate and climate change
Over the past 70 years since the foundation of the People's Republic of China, Chinese scientists have made great contributions to various fields in the research of atmospheric sciences, which attracted worldwide attention.

A CERN for climate change
In a Perspective article appearing in this week's Proceedings of the National Academy of Sciences, Tim Palmer (Oxford University), and Bjorn Stevens (Max Planck Society), critically reflect on the present state of Earth system modelling.

Fairy-wrens change breeding habits to cope with climate change
Warmer temperatures linked to climate change are having a big impact on the breeding habits of one of Australia's most recognisable bird species, according to researchers at The Australian National University (ANU).

Believing in climate change doesn't mean you are preparing for climate change, study finds
Notre Dame researchers found that although coastal homeowners may perceive a worsening of climate change-related hazards, these attitudes are largely unrelated to a homeowner's expectations of actual home damage.

Older forests resist change -- climate change, that is
Older forests in eastern North America are less vulnerable to climate change than younger forests, particularly for carbon storage, timber production, and biodiversity, new research finds.

Read More: Climate Change News and Climate Change Current Events is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to