The startling scenes of urban devastation in Texas following Hurricane Harvey and in Florida, Georgia and South Carolina following Hurricane Irma are a microcosm of what climate change holds for major cities throughout the world—and a wake-up call for the United States that it is time to get serious about climate adaptation both at home and abroad.

The horrendous impacts of Harvey on Houston, Beaumont, Port Arthur and other Texas communities and of Irma on the Florida Keys, Tampa, St. Petersburg on the west, Miami on the east and Charleston on the north have revealed in the starkest terms the need for both short and long-term adaptation to climate change in urban areas. The short-term recovery cost alone for Texas is likely to cost well over the $80 billion that Sandy required in the New York area, and long-term relocation of critical roads, water treatment facilities, power plants, industrial facilities, and entire neighborhoods will almost certainly bring the total cost closer to $200 billion. Recovery in Florida, which was better prepared because of lessons learned from previous hurricanes, will surely run to tens of billions as well. Fortunately, Texas, Florida and the U.S. Congress have, collectively, the financial resources, technical skills and public and private institutions to carry out both near-term recovery and longer-term resiliency planning (whether they will do so is another matter). But what of the many small and large cities in the world—especially in developing countries—that are already experience equally or greater climate-related destruction but do not have access to any significant resources to help their residents survive floods, droughts, heat waves and loss of basic services like water, electricity, hospitals, transportation and police?

Americans responded with concern, courage and generosity to the heartbreaking scenes of Houston's flooded neighborhoods (and 38 reported deaths) and to the widely-reported scenes of Austin's 118,000 citizens doing without potable water for nearly a week (until bottled water could be delivered to the city) and hospital and nursing home patients being evacuated by air. Similar scenes are now playing out in Florida, where many elderly residents were unable to join the large-scale evacuation ordered by state and local authorities. At the same time, however, more than 1,000 people died or were missing in rain-induced mudslides in Freetown, Sierra Leone, flooding killed more than another 1,000 people in Bangladesh, Nepal and India and millions of people have been displaced by flooding in other parts of Asia, virtually all as a result of climate change. Many other megacities in the developing world, with far larger populations than Houston, Miami or even New York, are facing similar threats to millions of their citizens as a result of a changing climate that they had little or no role in causing and have the fewest resources to combat.