SW-NCA-color-FINALweb

414 assessment of climate change in the southwest united statesFigure 18.3 McKinsey Mitigation Cost Curve. Governments, for-profit and non-profit organizations,and individuals are already taking steps to reduce the causes of climate change in the Southwest.Many low-cost or negative-cost opportunities for emission reductions (particularly energy efficiency andrenewable energy) are available. This well-known graphic shows a wide range of actions that incur costsavings (with “negative costs” shown on the left side of the graphic with bars extending below thehorizontal line). Actions to the right of the graphic incur increasingly higher costs. The width of each barassociated with a particular action indicates how much carbon could be abated in 2030 throughout theUnited States if it were implemented fully (in gigatons of carbon per year). Graph based on McKinsey(2007).18.5 Adaptation Options in the SouthwestMany of the chapters in this report show that impacts of climate change are not onlyexpected to occur in the future, but are already beginning to manifest across the Southwest.This implies that reducing emissions (i.e., mitigation) cannot be the only responseto climate change. Efforts are now also required to prepare for, plan for, and minimizethose impacts that cannot be avoided and turn expected climate changes into opportunitieswherever possible (i.e., adaptation). ii