Given past and current emission levels, the planet is already committed to significant climate change. Strong mitigation efforts can head off some of the most serious potential impacts but cannot prevent significant harm, particularly in vulnerable areas such as the arid western United States. Impacts on water supply are particularly worrisome, but a variety of other impacts are also forecast. Coping with these impacts will require retooling water systems, changing agricultural practices, reconsidering development patterns, creating conservation measures for endangered species, and other interventions into societal practices. Many of these impacts revolve around water: its supply, its uses, its flood risks.

We need to ensure that we evaluate adaptation needs through a sensible, well-designed process, and we can learn a lot from the shortcomings of existing processes for assessing environmental impacts. When we prepare Climate Adaptation Statements, we should benefit from our experience with environmental impact statements (EISs). We should take advantage of what we have learned from our experience with existing procedures rather than replicating their flaws.