The nearly 11 million Mexican immigrants in the United States represent almost one-quarter of the country’s entire immigrant population, and as such are the largest foreign-born group. But their numbers have been declining, shrinking by 7 percent between 2010 and 2019. Among recently arrived immigrants, those from China and India now outpace Mexicans for the first time.

Climate change is affecting human movement now, causing internal displacement and international migration, and will do so in the future. But the impact is often indirect, and rarely is the process as straightforward as one might think. This article provides an overview of research on how climatic hazards drive and affect migration, reviewing which types of people might migrate and under what conditions.