Both the magnitude and rate of climate change are important in determining the sensitivity, adaptability, and vulnerability of a system. These chapters describe these technologies, assess estimates of their potential financial and environmental costs and benefits, and evaluate case studies of how these technologies can be applied. One conclusion that emerges strongly from the chapters of the Assessment is that human-induced climate change represents an additional stress on systems that already are threatened by other global changes. These other changes include habitat fragmentation, intensified resource use, contamination by organic and inorganic pollutants, acid deposition, and increased UV-B penetration due to thinning of the ozone layer. A second conclusion of the Assessment is that governments will continue to face the challenge of deciding how to respond to climate change-related risks in a situation of uncertainty.
Researchers can estimate a system's sensitivity to changes in specific attributes of climate.
However, because environmental and human systems are so complex, and because so many environmental and non-environmental factors are expected to change simultaneously, it is extremely difficult to attribute ecological or social impacts solely to climate change. The Working Group II assessment does, however, indicate that governments have attractive options for positioning themselves to better cope with possible outcomes of climate change. Options also are available for mitigating greenhouse gas emissions with the help of both existing and emerging technologies. The drafting process began in June 1993 at an IPCC plenary meeting, where the basic report structure was approved. Lead authors met 3 months later to finalize the chapter outlines.