By Deborah Netburn

Los Angeles Times

Scientists have figured out the climate forecast for the year 2080 in hundreds of cities across North America, and it looks like it’s going to get a whole lot warmer in all of them.

If humanity continues to emit greenhouse gases at the same rate it does today, in 60 years Los Angeles’ climate will most closely resemble the current climate of Cabo San Lucas, at the southern tip of Baja California in Mexico. Portland, which averages 155 rainy days per year, will feel like Sacramento, the California state capital, where only 59 days of the year have rain in them. And the New York City of the future will be like the Jonesboro, Arkansas, of today, according to a new study in Nature Communications.

“From a beach-day perspective, warmer might be better, but it is not better for our food production and in some areas it could lead to more pests, invasive species and disease,” said study leader Matthew Fitzpatrick, a biogeographer at the University of Maryland’s Center for Environmental Science.

Aedes mosquitoes, which transmit Zika, dengue and other deadly viruses, prefer warmer weather and may be able to spread into new areas of the U.S. as temperatures climb, scientists said.

On the West Coast, warmer temperatures are associated with more smog, which can be dangerous to people with asthma and allergies, and a decline in water quality.

Scientists have been warning about rising temperatures for years. In the new work, Fitzpatrick and his colleague Robert Dunn of North Carolina State University set out to make these projections more tangible thanks to a technique called climate analog mapping. It involves matching the expected future climate of one city with the current climate of another.

To do this, they started with climate model projections for 540 cities throughout North America, looking specifically at average maximum temperature, average minimum temperature and total precipitation in all four seasons in the year 2080. Then they used a computer program to find the city whose current climate most closely matched each projection.

The results show that in the eastern half of the U.S. and Canada, urban areas will most closely resemble cities that are 500 miles to the south. For example, the climate in Montreal in 2080 will most resemble the climate in Philadelphia today.

The story is more complicated in the West because the topography is more extreme, and because factors including proximity to the ocean influence the climate. For example, the authors report that the closest present-day equivalent to the climate of 2080 San Diego is Westmont, which lies about 120 miles north of San Diego between Inglewood and Watts in Los Angeles County.

Many cities did not have good analogs for their expected 2080 climate, including Los Angeles. By the year 2080, temperatures in L.A. are expected to resemble those now occurring in Cabo San Lucas, but it won’t have Cabo’s pattern of precipitation. This suggests that by 2080, large parts of the country will experience a climate that has never before seen in the United States.

Fitzpatrick added that some of the North American cities might have better analogs elsewhere in the world, but he and Dunn chose to limit their search to the Western Hemisphere. “We don’t think most Americans will know what the climate is like in a city in China or India,” Fitzpatrick said. “The goal is to make climate change less abstract and something people can relate to based on their own experiences.”

22541004