Change (IPCC) includes the widest array of disciplines of all the IPCC working groups. It has taken some time for this group to synthesize the wide range of research in the field and to develop clear messages that are easily communicated to the larger IPCC process. However, in the fourth IPCC assessment, integration of Group II’s findings in the final synthesis report for policy makers represented significant progress.
The field of climate vulnerability, impacts and adaptation is gaining greater recognition, but researchers need to continue the hard work of advancing our methodologies. This work will require funding and self-organization. The intensity of IPCC meeting and report schedules has not provided opportunities for the research community to evaluate the IPCC process, identify institutional needs, or explore follow-up options. The present meeting is unique in offering this venue, and is timely in following closely after the release of the IPCC’s fourth assessment report.
Martin Parry, cochair of IPCC Working Group II, talked about trends in climate change and responses, research priorities, and the IPCC process.
Parry pointed out that global greenhouse gas emissions are accelerating, including CO2 (carbon dioxide) as the largest contributor. Without mitigation, these emissions will continue to grow. Since the third IPCC assessment in 2001, the upper range of projected temperature increases has been revised upward, and a greater range of uncertainty has been established. Of 29,000 data sets on environmental trends, 90 percent of observed trends are in the direction expected from anthropogenic warming. These trends can be seen on every continent.
Some climate effects may be occurring faster than expected. Such effects present policy challenges, but they also provide opportunities to gain information useful to future adaptation planning. For example:
Early identification of the most vulnerable regions and sensitive sectors has begun, although reporting and results are limited thus far.
Some ecosystem changes, including species extinctions, have now been quantitatively assessed.
Reduced water availability is a primary driver of secondary impacts, especially in the dry tropics.
Crop yield responses will vary regionally, but many projections trend downward, with greater temperature increases, especially in low latitudes.