Among the earliest examples of the disruptions that climate change can bring, some low-lying island countries in the Pacific Ocean are facing serious threats from rising sea levels and coastal erosion. Over the long term, atoll nations such as Kiribati, Tuvalu, and the Marshall Islands might eventually need to relocate some or all of their populations. But not everyone wants to migrate, and governments have balanced supporting people who relocate with other ways of adapting to changing conditions.