Study: Contemporary climatic analogs for 540 North American urban areas in the late 21st century @nature_org

Here’s the abstract (Matthew C. Fitzpatrick & Robert R. Dunn):

A major challenge in articulating human dimensions of climate change lies in translating global climate forecasts into impact assessments that are intuitive to the public. Climate-analog mapping involves matching the expected future climate at a location (e.g., a person’s city of residence) with current climate of another, potentially familiar, location – thereby providing a more relatable, place-based assessment of climate change. For 540 North American urban areas, we used climate-analog mapping to identify the location that has a contemporary climate most similar to each urban area’s expected 2080’s climate. We show that climate of most urban areas will shift considerably and become either more akin to contemporary climates hundreds of kilometers away and mainly to the south or will have no modern equivalent. Combined with an interactive web application, we provide an intuitive means of raising public awareness of the implications of climate change for 250 million urban residents.

From Earther (Brian Kahn):

When your grandchildren plan a trip to Denver later this century, they’ll need to leave the winter hat at home and instead plan like they’re going to the Texas Panhandle.

That’s according to a new study published on Tuesday in Nature Communications, which looked at the future climate of 540 cities in North America and drew comparisons with cities of today. The results show that cities’ climates will, at the end of the century, look more like cities 528 miles south do today if emissions continue rising in line with current trends. That will rearrange more than vacation plans as city residents will be forced to cope with more intense heat and the dangerous impacts that came with it. The study also shows that if we begin to cut emissions, cities’ climates will still change but the shift will be far less dramatic.

Heat is something visceral and that’s partly why the scientists undertook the study. Matthew Fitzpatrick, a scientist at the University of Maryland Center for Environmental Science who led the study, told Earther that despite working with climate data on a regular basis, he really wanted to understand what rising temperatures would mean for him. He started his analysis looking to answer the question of what Washington, D.C.’s future climate would look like and then expanded the analysis to 539 other cities.

To undertake the analysis, he and his co-author used two climate model simulations: One where emissions continue to grow on their current trends and another where humanity reins emissions in starting in midcentury. They then took the temperature of the 540 cities under those two scenarios and compared them to city climates of today, finding a best fit.

The results show a massive southward migration of hundreds of miles for nearly all cities’ climates under both emissions scenarios, but particularly if emissions keep going up. The biggest moves distance-wise are in the eastern U.S. and along the Pacific Coast because there’s less topographic variety. While western cities’ climate analogs can sometimes just be found downslope where things are warmer, eastern and coastal cities’ analogs are often much further away. That’s how you end up with Washington, D.C. feeling like it’s in Mississippi, San Francisco feeling like Los Angeles and Los Angeles feeling like the tip of Baja California by century’s end if emissions continue. Or take Anchorage, which will feel like Powell River, British Columbia located more than 1,200 miles south.

Actually it’s a poleward march by the tropics.

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