This report is a joint effort of the Southwest Regional Climate Hub and the California Subsidiary Hub (Sub Hub). The Southwest Regional Climate Hub covers Arizona, California, Hawai‘i and the U.S. affiliated Pacific Islands, Nevada, New Mexico, and Utah and contains vast areas of western rangeland, forests, and high-value specialty crops (Figure 1). The California Sub Hub works with the issues of climate change effects on forests and agriculture in California, including internationally important specialty crops. The southwestern region contains high climatic diversity, with locations that claim the highest and lowest amounts of annual precipitation, and the highest and lowest elevations in the 48 contiguous states. Within the region, producers cope with severe drought effects on crop and animal systems, catastrophic wildfires, insect outbreaks, and sea level rise. The Southwest States grow diverse agricultural crops, including cotton, lettuce, tree fruit, cantaloupes, grapes, onions, macadamia nuts, coffee, and pecans. The region relies on irrigation more heavily than any other region in the United States. Water supplies, primarily from winter snowfall in the Sierra Nevada and Rocky Mountains, are critical to meeting irrigation needs in the Southwest. Total farm income for the region exceeded $56 billion in 2012, $45 billion of which was produced in California. Livestock account for approximately one-third of the agricultural profits in these six States.