For the past 50 to 75 years, national migration trends have favored mobility from the Frostbelt to the Sunbelt. Recent research projects that in the coming decades, climate change will dramatically change where people choose to live.
The U.S. Census Bureau recently released state population growth figures from mid-2022 to mid-2023. Southeastern, South Central and Mountain states saw reasonably healthy growth, while Northeastern, Midwestern and Pacific Coast states saw only modest growth with even some declines peppered in. These recent trends extend a pattern of population growth that we’ve seen in recent decades.
Over the past 50 years, places that have seen the greatest percentage population growth are the Mountain West, South Atlantic and South Central regions. Those with the slowest growth are heavily concentrated in the Northeast and Midwest.
Natural growth (the number of births minus the number of deaths) is a major factor in state population trends. However, the key factor in population growth for most states is migration trends. People move from one state to another in part for family reasons, but employment and housing opportunities typically are the greatest influence on these decisions. States that have seen the greatest population gains over the past half century have tended to rank favorably for jobs and housing.
However, these long-term patterns of state migration are expected to change over the coming 25 years, according to an ambitious study conducted by researchers at the Federal Reserve Bank of San Francisco that looks at the impact of climate change on population shifts. Their approach was to analyze county-level temperature and precipitation patterns from the early 1950s to the present and compute their relationship to populations shifts. They then used county-level projections for temperature and precipitation to the year 2050 to estimate their likely impact on future population migration flows.
Adaptation to climate change can be a complicated process extending over a long period of time. As the authors note, governments, businesses and households may invest in more resilient infrastructure to offset the negative impacts of climate change. However, many businesses and households could be expected to move away from places where the climate is expected to worsen to places where it is expected to worsen less or even improve. In fact, this response to climate change is already occurring. The study’s projections represent a continuation and acceleration of a pattern in place since at least the 1980s where the connection between population growth and unfavorable climates began to turn negative.
Using the most likely scenarios of climate change, the study identifies areas of the country that are expected to see a significant increase or decrease in population growth relative to national trends in coming decades. Areas expected to see population growth of 50 percent or more than the national average to the year 2050 include northern New England states (Vermont, New Hampshire and Maine), northern Midwestern states (Michigan, Wisconsin, Minnesota, North Dakota and parts of South Dakota), and parts of Mountain States (Montana, Idaho, Wyoming, and Colorado). Areas expected to see population growth 50 percent or more below the national average include most to the southern U.S. from North Carolina all the way over to southern California.
The gradual adaptation of locational choices to evolving changes in climate is a slow and uneven process. However, the implications are very significant in terms of where future economic growth is expected to occur. Where are future homes and commercial facilities likely to be constructed? Where is future business investment likely to occur? Should government policies be oriented to reverse or to facilitate these migration patterns? These are complicated questions, but ones that are critical to consider.
Kermit Baker is the chief economist at the American Institute of Architects. He can be reached by email at kbaker@aia.org.