The new assessment by the Intergovernmental Panel on Climate Change (IPCC), which is jointly sponsored by the United Nations Environment Programme (UNEP) and the World Meteorological Organization, projects a potentially devastating global warming of 1.4 - 5.8°C over the coming century. "Intensive climate research and monitoring over the past few years has given scientists greater confidence in their understanding of the causes and effects of global warming," said UNEP Executive Director Klaus Töpfer. "The scientific consensus presented in this comprehensive report about human-induced climate change should sound alarm bells in every national capital and in every local community.
We must move ahead boldly with clean energy technologies, and we should start preparing ourselves now for the rising sea levels, changing rain patterns, and other impacts of global warming," he said. The IPCC's Third Assessment Report is being written and reviewed by hundreds of climate change experts on the basis of the most up- to-date, peer-reviewed research available. In addition to today's Volume I with the title "Climate Change 2001: The Scientific Basis" the IPCC Report will include a Volume II on impacts (to be finalized in mid-February) and a Volume III on response strategies (early March). "The scientific findings being reported today should convince governments of the need to take constructive steps towards resuming the climate change talks that stalled last November in The Hague," said Michael Zammit Cutajar, Executive Secretary of the UN Climate Change Convention.
Some of the report's key findings are:
* There is new and stronger evidence that most of the warmingobserved over the last 50 years is attributable to human activities. Since the IPCC's 1995 Report confidence in the ability of models to project future climate has increased. For example, there is now a longer and more closely scrutinized temperature record. Reconstructions of climate data for the past 1,000 years, as well as model estimates of natural climate variations, suggest that the observed warming over the past 100 years was unusual and is unlikely to be entirely natural in origin. In addition, detection and attribution studies consistently find evidence for an anthropogenic signal in the climate record of the last 35-50 years. However, there are still many remaining gaps in information and understanding about climate change.
* An increasing body of observation gives a collective picture of a warming world.
* Globally it is very likely that the 1990s were the warmest decade, and 1998 the warmest year, in the instrumental record, since 1861. New analyses of data from tree rings, corals, ice cores and historical records for the Northern Hemisphere indicate that the increase in temperature in the 20th century is likely to have been the largest of any century during the past 1000 years, and it is likely that the 1990s were the warmest decade and 1998 was the warmest year.
* In the mid- and high-latitudes of the northern hemisphere, it is very likely that snow cover has decreased by about 10% since the late 1960s, and the annual duration of lake- and river-ice cover has shortened by about two weeks over the 20th century. It is likely that there has been about a 40% decline in Arctic sea-ice thickness during late summer to early autumn in recent decades.
* Since 1750, the atmospheric concentration of carbon dioxide has increased by 31% from 280 parts per million to about 367 ppm today. The present CO2 concentration has not been exceeded during the past 420,000 years and likely not during the past 20 million years.
* The globally averaged surface temperature is projected to increase by 1.4 - 5.8°C from 1990 to 2100. This is higher than the 1995 Second Assessment Report's projection of 1 - 3.5°C, largely because future sulphur dioxide emissions (which help to cool the Earth) are now expected to be lower. This future warming is on top of a 0.6°C increase since 1861.
* Global average water vapour concentration and precipitation are projected to increase. More intense precipitation events are likely over many northern hemisphere's mid- to high-latitude land areas. The observed intensities and frequencies of tropical and extra-tropical cyclones and severe local storms, however, currently show no clear long-term trends, although data are often sparse and inadequate.
* Sea-levels are projected to rise by 0.09 to 0.88 metres from 1990 to 2100. Despite higher temperature projections these sea level projections are slightly lower than the range projected in the SAR (0.13 to 0.94 metres), primarily due to the use of improved models, which give a smaller contribution from glaciers and ice sheets. Over 150 delegates from about 100 governments participated in the working group meeting. The full report is over 1000 pages, has been three years in production, and was written by 123 lead authors, assisted more than 516 contributing authors. The delegates unanimously accepted the report and approved the Summary for Policymakers.
Note to journalists: For more information, please contact Tim Higham in Shanghai until 23 January, at email@example.com,+86-21-64845667, +44 781 8428339 (mobile),
or Michael Williams in Geneva at +41-22-9178-242/244/196, +41-79-409-1528 (portable)
or firstname.lastname@example.org. (Requests for interviews with Klaus Töpfer should be arranged on Monday through Michael Williams in Geneva).
The report's Summary for Policymakers is available at http://www.ipcc.ch.
UNEP News Release 01/5