53. What can be done to improve knowledge for future decisions?
Action is needed in several areas. Collection and dissemination of data that provide an uninterrupted record of the evolving climate and of data that are needed for the improvement and testing of climate models should be expanded. Weather forecasts should be improved, especially of extremes, for weeks and seasons to ease adaptation to climate change. The mechanisms that play a significant role in the responses of the climate to changing concentrations of greenhouse gases need further identification, and quantification at scales appropriate for climate models. Field research should be conducted on entire systems of species over many years to learn how CO2 enrichment and other facets of greenhouse warming alter the mix of species and changes in total production or quality of biomass. Research on social and economic aspects of global change and greenhouse warming should be strengthened.
54. Do geoengineering options really have potential?
Preliminary assessments of these options suggest that they have large potential to mitigate greenhouse warming and are relatively cost-effective in comparison to other mitigation options. However, their feasibility and especially the side-effects associated with them need to be carefully examined. Because the geoengineering options have the potential to affect greenhouse warming on a substantial scale, because there is convincing evidence that some of these cause or alter a variety of chemical reactions in the atmosphere, and because the climate system is poorly understood, such options must be considered extremely carefully. If greenhouse warming occurs, and the climate system turns out to be highly sensitive to radiative forcing, they may be needed.
55. What should the United States do at the international level?
The United States should resume full participation in international programs to slow population growth and contribute its share to their financial and other support. In addition, the United States should participate fully in international agreements and programs to address greenhouse warming, including representation by officials at an appropriate level.