Risks Of Disasterous Climate Change Increasing, Scientists Warn

(ENS) -- The rapid thinning of the Antarctic ice sheet is making global sea level rise a cause for concern, according to the Director of the British Antarctic Survey, Professor Chris Rapley. Speaking this week at a conference on avoiding climate change hosted by the British government, Rapley warned that the melting of ice shelves which have been present since the last ice age may speed up glacial melt in a "cork out of bottle" effect.

"Satellite measurements tell us that a significant part of the West Antarctic ice sheet in this area is thinning fast enough to make a significant contribution to sea level rise," Rapley said.

Predictions made by British Antarctic Survey scientists in 1998 that the warming of the Antarctic Peninsula region would put several ice shelves at risk were realized in 2002 when, in less than a month, 500 billion metric tons of ice from the Larsen B ice shelf broke up into thousands of small icebergs.

The latest published research suggests that "ice shelves may have an important role in stabilizing the ice sheet in Antarctica, and imply that the future loss of the largest ice shelves in the Antarctic could eventually cause accelerated and dramatic sea level rise," Rapley said.

The last report of the Intergovernmental Panel on Climate Change (IPCC) in 2001 called Antarctica a sleeping giant in terms of climate change, recalled Rapley. "I would say that this is now an awakened giant. There is real cause for concern," he warned.

The conference, called Avoiding Dangerous Climate Change: A Scientific Symposium on Stabilization of Greenhouse Gases, took place at the invitation of the British Prime Minister Tony Blair and under the sponsorship of the UK Department of Environment, Food and Rural Affairs (DEFRA).

Some 200 internationally renowned scientists from 30 countries gathered February 1-3 at the new headquarters of the Met Office's Hadley Center for Climate Prediction and Research, the UK's leading center for climate research.

Climate change is at the top of the UK's agenda during its G8 presidency this year. At the opening of the conference on Tuesday, Environment Secretary Margaret Beckett said, "An international approach to dealing with climate change is vital."

The conference offered a unique opportunity for scientists to exchange views on the consequences and risks to natural and human systems as a result of changes in the world's climate.

Major themes included key vulnerabilities of the climate system and critical thresholds, socio-economic effects both globally and regionally, emission pathways to stabilize greenhouse gases, and technological options to achieve stabilization levels.

The Steering Committee report at the close of the conference said, "There is greater clarity and reduced uncertainty about the impacts of climate change across a wide range of systems, sectors and societies. In many cases the risks are more serious than previously thought."

A number of new impacts were identified that are "potentially disturbing," the Steering Committee wrote. "One example is the recent change that is occurring in the acidity of the ocean. This is likely to reduce the capacity to remove CO2 [carbon dioxide] from the atmosphere and affect the entire marine food chain."

Carol Turley of the Plymouth Marine Laboratory presented new data showing the marked acidification of the oceans due to atmospheric carbon dioxide enrichment. This acidification is likely to result in drastic changes in marine ecosystem structure and biogeochemical cycling with major impacts on the ocean carbon fluxes, she said.

Changes to polar ice and glaciers and rainfall regimes have already occurred, the scientists said.

Many climate impacts, particularly the most damaging ones, will be associated with an increased frequency or intensity of extreme events, the scientists agreed. "This is an important area for further work since many studies do not explicitly take into account the effects of extremes, although it is known that such extremes pose significant risks to human wellbeing. The heat-wave that affected Europe in 2003 is a prime example," they wrote.

Africa could bear the brunt of the damage from human induced climate change, according to Bill Hare, visiting scientist, Potsdam Institute for Climate Impact Research.

The Steering Committee called for immediate "major investment" to deal with both mitigation of climate warming and adaptation to it. The first is essential to minimize future impacts, the committee said, and the latter is essential to cope with impacts which cannot be avoided in the near to medium term.

In his keynote speech, IPCC Chairman Dr. Rajendra Pachauri of India observed that "dangerous" climate change requires a value judgment but that such judgments should be based on the principles of universal human rights and the needs of future generations, as exemplified in concept of sustainable development.

Science can provide essential information on impacts and damage, taking into account socio-economic dimensions, Pachauri said. He said it is be important to consider who would be affected and the timescale for dangerous effects to become apparent.

At the same time Pachauri stressed the importance of mitigation in furthering sustainable development goals and implementing "no regrets" options.

Pachauri outlined the potential for major changes to the climate system, which could overwhelm human response strategies -- breakdown of the thermohaline circulation, disintegration of the West Antarctic Ice Sheet, a shift in mean climate towards an El Nino-like state, reduced carbon sink capacity, methane release from hydrates, and a rearrangement of biome distributions.

He called attention to the inertia in the climate system and the length of time that it takes for mitigation actions to impact on temperatures and sea levels.

John Lanchbery from the Royal Society for the Protection of Birds told his colleagues that on the basis of ecological effects and the observed inability of some natural ecosystems to adapt, atmospheric concentrations of greenhouse gases are already too high.

Lanchbery said that climate impacts on plankton abundance in the North Sea already have resulted in a substantial reduction in sand eel numbers -- a key food species for many seabirds.

This shortage has been independently indicated by Danish sand eel fisheries where catches in 2003 and 2004 were half the typical catch.

Several scientists warned that as climate changes, societies will also change, and the "flood of refugees" out of some parts of the world could be significant.

Papers presented by the IPCC's Martin Parry, Yuri Izrael from the Institute of Global Climate and Ecology, and other speakers during the Impacts Overview session, illustrated from different perspectives that the consequences of climate change vary with scale, from global to community level, and between regions.

New technologies are likely to emerge, new discoveries will be made and population shifts are bound to occur, they said. Forecasting such changes is extremely difficult, but climate change impacts analyses must take into account changes to societies and how they will adapt.

At the close of the conference last night, Beckett said, "I hope that this conference will be seen as a milestone in building international consensus on climate change."