In one generation, the climate experienced in many North American cities is projected to change to that of locations hundreds of miles away—or to a new climate unlike any found in North America today. The Future Urban Climates interactive web application aims to help the public understand how climate change may impact the lives of a large portion of the population of the United States by matching the expected future climate in each city with the current climate of another location, providing a relatable picture of what is likely in store.
Future Urban Climates
By the 2080s, the climate of North American urban areas will feel substantially different, and, in many cases, completely unlike contemporary climates found anywhere in the western hemisphere north of the equator. If emissions continue unabated throughout the 21st century,the climate of North American urban areas will become, on average, most like the contemporary climate of locations about 500 miles away and mainly to the south.
The climate of cities in the northeast will tend to feel more like the humid subtropical climates typical of parts of the Midwest or southeastern U.S. today—warmer and wetter in all seasons. For instance, Washington, D.C. will feel more like northern Mississippi. The climates of western cities are expected to become more like those of the desert Southwest or southern California—warmer in all seasons, with changes in the amount and seasonal distribution of precipitation. San Francisco’s climate will resemble that of Los Angeles.
How it was done
Scientists analyzed 540 urban areas that encompassed approximately 250 million inhabitants in the United States and Canada. For each urban area, they mapped the similarity between that city’s future climate expected by the 2080s and contemporary climate in the western hemisphere north of the equator using 12 measures of climate, including minimum and maximum temperature and precipitation during the four seasons.
The study also mapped climate differences under two emission trajectories: unmitigated emissions (RCP8.5), the scenario most in line with what might be expected given current policies and the speed of global action, and mitigated emissions (RCP4.5), which assumes policies are put in place to limit emissions, such as the Paris Agreement.
Climate-analog mapping is a statistical technique that matches the expected future climate at one location—your city of residence, for instance—with the current climate of another familiar location to provide a place-based understanding of climate change. Combining climate mapping with the interactive web application provides a powerful tool to communicate how climate change may impact the lives of a large portion of the population of the United States and Canada.
The paper, “Contemporary climatic analogs for 540 North American urban areas in the late 21st century,” by Matt Fitzpatrick of the University of Maryland Center for Environmental Science and Robert Dunn of North Carolina State University, was published in Nature Communications in February 2019.