Avoiding Dangerous Climate Change

A conference by this title was held in Exeter from 1 to 3 February 2005 under the sponsorship of the government of the United Kingdom. Its aim "was to advance scientific understanding of and encourage an international scientific debate on the long term implications of climate change, the relevance of stabilisation goals, and options to reach such goals; and to encourage research on these issues."

Now the results of that conference have been published, and a portion of the book (by the same title) is available online, free.

The report suggests that rising concentrations of greenhouse gases may have more serious impacts than previously believed. The UK government is concerned that there is only a small chance of greenhouse gas emissions being kept below "dangerous" levels.

The Executive Summary states:

A regional increase above present levels of 2.7 degrees Centegrade may be a threshold that triggers melting of the Greenland ice-cap, while an increase in global temperatures of about one degree Centegrade is likely to lead to extensive coral bleaching. In general, surveys of the literature suggest increasing damage if the globe warms about 1 to 3 degrees Centegrade above current levels. Serious risk of large scale, irreversible system disruption, such as reversal of the land carbon sink and possible destabilisation of the Antarctic ice sheets is more likely above 3 degrees Centegrade. Such levels are well within the range of climate change projections for the century. While a clear temperature threshold has not been identified for shutdown of the Atlantic thermohaline circulation, studies were presented suggesting that a shutdown becomes more likely with increasing temperature. In this context, some felt that it would be useful to agree upon a set of critical thresholds that we should aim not to cross. Others noted it would be difficult to objectively choose such a level.

The impacts of climate change are already being observed in a variety of sectors. Ecosystems are already showing the effects of climate change. Changes to polar ice and glaciers and rainfall regimes have already occurred. While consistent with model projections the links to anthropogenic climate change need to be investigated further.

Many climate impacts, particularly the most damaging ones, will be associated with an increased frequency or intensity of extreme events. 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 well being. The heat-wave that affected Europe in 2003 is a prime example.

The impacts of climate change are already being observed in a variety of sectors. Ecosystems are already showing the effects of climate change. Changes to polar ice and glaciers and rainfall regimes have already occurred. While consistent with model projections the links to anthropogenic climate change need to be investigated further.

Many climate impacts, particularly the most damaging ones, will be associated with an increased frequency or intensity of extreme events. 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 well being. The heat-wave that affected Europe in 2003 is a prime example.

Read BBC News coverage of the report.