Adapting to climate change will require more than fortifying coastlines and preparing for warmer temperatures. It will require a careful look at how we manage our water resources. Nearly a decade of observations from the twin GRACE satellites shows that some parts of the United States could face hard times in coming years. This map shows how water supplies have changed between 2003 and 2012. GRACE measures subtle shifts in gravity from month to month. Variations in land topography or ocean tides change the distribution of Earth's mass; the addition or subtraction of water also changes the gravity field. In the past decade, groundwater supplies have decreased in California's Central Valley and in the Southern High Plains (Texas and Oklahoma), places that rely on ground water to irrigate crops. Eastern Texas, Alabama, and the Mid-Atlantic states also saw a decrease in groundwater supplies because of long-term drought. The current decrease in water reserves highlights the need to monitor and manage ground water resources for the future.