Introduction

In the coming decades, climate change will drive unprecedented levels of displacement and migration across the globe. Sea-level rise, extreme heat and drought, and natural disasters such as tropical storms, flooding, and wildfires will prompt individuals and communities to seek refuge in more climate-resilient regions. As early as 1990, a report by the Intergovernmental Panel on Climate Change warned that “the greatest single impact of climate change could be on human migration,” and researchers predict that as many as 300 million people worldwide will become displaced due to climate impacts in this century.

Like the rest of the planet, the United States will likely experience major population shifts due to climate change. Domestic migration patterns will depend in large part on geography, the type and level of climate risk, and socioeconomic status. For middle- and high-income households, relocation may be a proactive adaptation strategy to mitigate physical and financial risk. Many poorer Americans, meanwhile, could be stuck in place, only to move after a catastrophic natural disaster or due to unlivable climate conditions.

By one estimate, 50 million Americans could move due to climate impacts in the next three decades. Across the southern half of the country, one in 12 residents may move towards California, the Rockies, or the Pacific Northwest. Climate haven cities in the Northwest and Northeast should expect to grow by roughly 10 percent.

But many Americans will move within their own state or region. Previous research on post-disaster migration in the United States suggests that many displaced persons relocate to nearby communities. Analysis by the Urban Institute, for instance, found that most California households affected by wildfires in 2015 and 2017 moved to neighboring counties. Safe harbor cities across the climate-vulnerable U.S. South, including Austin, Orlando, Atlanta, and Riverside, could each receive over a quarter million new residents due to sea-level rise alone, by 2100.

In many U.S. communities, climate driven-population growth could exacerbate the affordable housing crisis, increase economic competition, and risk overwhelming public infrastructure and social services. The city of Chico in northern California is a stark example of these challenges. A sudden inflow of disaster-displaced households from nearby Paradise, largely destroyed in the 2018 Camp Fire, intensified Chico’s housing shortages, overburdened post-disaster assistance, and led to a significant increase in homelessness. Future safe harbor cities across the South and elsewhere could very likely experience similar challenges. Austin already lacks over 150,000 affordable homes,¹ while Atlanta may lose its water supply to drought by 2100 as its population swells.

By contrast, some northern cities view climate migration as a socioeconomic opportunity. Buffalo, New York, and Duluth, Minnesota, are currently positioning themselves as climate havens, in anticipation that an inflow of climate migrants will help to improve the local economy and reverse population loss as a result of deindustrialization. Buffalo is indicative: The city experienced a 50 percent decline in population between 1950 and 2021, yet its inland location and proximity to Lake Erie’s freshwater mean that it is relatively well-positioned to withstand climate change and thrive socioeconomically.

Federal, state, and local decision makers must respond to these projected demographic shifts in the coming decades with proactive policies that ensure an adequate supply of safe and affordable housing, as well as infrastructure, services, and economic opportunities that can support large population increases. If implemented effectively, such policies can not only mitigate any adverse effects of rapid population growth, but also harness the potential socioeconomic benefits of migration for both newcomers and receiving communities.²

This report explores how climate change will influence future migration within the United States and how these demographic changes will impact housing security in receiving communities. It provides actionable recommendations for federal, state, and local policymakers to ensure that population inflows lead to economic growth and opportunity rather than crisis for the cities and towns projected to receive domestic climate migrants in the coming decades.