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Global Climate Change Digest
A Guide to Information on Greenhouse Gases and Ozone Depletion
Published July 1988 through June 1999

FROM VOLUME 3, NUMBER 8, AUGUST 1990

NEWS...
IPCC PANEL REPORTS

Item #d90aug59

The three working groups of the Intergovernmental Panel on Climate Change completed their respective reports in June 1990, and a draft of the full IPCC report based on them should be ready in August. Working Group 1 (scientific assessment) finds with certainty that human emissions of greenhouse gases will enhance the natural greenhouse effect, by an amount which is still uncertain. It estimates, based on model results, that under the IPCC business-as-usual scenario of greenhouse gas emissions, global mean temperature will rise about 0.3° C per decade, with an uncertainty range of 0.2° C to 0.5° C per decade. An associated mean sea level rise of 0.6 cm per decade is expected. Under the most stringent assumptions considered for the restriction of greenhouse gas emissions, global mean temperature is still expected to rise by 0.1° C per decade.

To determine the impacts of climatic change, Working Group 2 used assumptions of slightly higher ranges of temperature and sea level rise, made prior to the revised estimates of Working Group 1. A wide range of impacts are discussed under the topics agriculture and forestry; terrestrial ecosystems; hydrology and water resources; oceans and coastal zones; seasonal snow cover, ice and permafrost; and finally human settlements, energy, transport, industry, human health and air quality. Extensive uncertainty underlies these predictions as well. For example, the group could not conclude whether average global agricultural output would increase or decrease, although substantial regional effects are likely. However, it estimates that global food production can be maintained at essentially the same level as would have occurred without climatic change, although the cost to achieve this is unclear. Extensive forest decline is expected because trees cannot adapt to rapid environmental change.

Development of the Working Group 3 report on policy responses culminated with difficult negotiations in a June meeting in Geneva, at which the United States, Canada, Japan and the USSR were joined by Saudi Arabia in opposing a move by western European countries to establish a specific timetable for developing a framework convention on greenhouse gases. The United States is the lead country for the group, and at a subsequent hearing Senator Albert Gore chided delegation head Frederick Bernthal for what he considered lack of leadership by the U.S. at the Geneva meeting. The group report details many possible response strategies, but (consistent with its original charge) does not advocate specific options or their timing. It recommends that international negotiations on a framework convention should start as soon as possible after the completion of the full IPCC report (anticipated in August), and recognizes that subject to their particular circumstances, individual nations may wish to consider taking steps now to stabilize greenhouse gases.

Each working group has published a 40-50-page "policymaker's summary" of its report, available from the IPCC Secretariat (41 Ave. Giuseppe-Motta, 1211 Geneva 20, Switz.; tel: 41-22-7308-235). In two recent issues of Nature, the editors discuss their intention to publish professional articles and information (social, economic and technical) that will help readers judge the quality of research on global warming being conducted by the IPCC and otherwise. (See p. 371, May 31, 1990, and p. 473, June 7.)

For articles relating to the IPCC Working Group reports see the following, as well as articles on Working Group 1 listed in Global Climate Change Digest, NEWS, July 1990:

"Communication Gaps Undermine Reports on Global Warming," D. MacKenzie, New Scientist, p. 27, June 23, 1990.

"Response Strategies Group Splits on--Climate Agreement," Intl. Environ. Rptr., pp. 278-279, July.

"Global Warming: Politics Muddle Policy," R. Monastersky, Science News, p. 391, June 23. Includes discussion of the Gore Senate hearing.

"Urgent Action Still Opposed," P. Aldhous, Nature, p. 562, June 14. Concerns Working Group 3.

"Gore Charges Administration with Letting Saudis Direct Greenhouse Panel Meeting," Greenhouse Effect Rep., p. 42, June.

"Modest Response to Climate Change Threat," P. Aldhous, ibid., p. 373, May 31.