WASHINGTON >> Starting in about a decade, Kingston, Jamaica, will probably be off-the-charts hot — permanently. Other places will soon follow. Singapore in 2028. Mexico City in 2031. Cairo in 2036. Phoenix and Honolulu in 2043. 

And eventually the whole world in 2047.

A new study on global warming pinpoints the probable dates for when cities and ecosystems around the world will regularly experience hotter environments the likes of which they have never seen before. 

And for dozens of cities, mostly in the tropics, those dates are a generation or less away.

To arrive at their projections, the researchers used weather observations, computer models and other data to calculate the point at which every year from then on will be warmer than the hottest year ever recorded over the last 150 years.

For example, the world as a whole had its hottest year on record in 2005. The new study, published today in the journal Nature, says that by the year 2047, every year that follows will probably be hotter than that record-setting scorcher.

Eventually, the coldest year in a particular city or region will be hotter than the hottest year in its past.

Study author Camilo Mora and his colleagues said they hope this new way of looking at climate change will spur governments to do something before it is too late. "Now is the time to act," said another study co-author, Ryan Longman.

Mora, a biological geographer at the University of Hawaii, and colleagues ran simulations from 39 different computer models and looked at hundreds of thousands of species, maps and data points to ask when places will have "an environment like we had never seen before."

The 2047 date for the whole world is based on continually increasing emissions of greenhouse gases from the burning of coal, oil and natural gases. If the world manages to reduce its emissions of carbon dioxide and other gases, that would be pushed to as late as 2069, according to Mora.

But for now, Mora said, the world is rushing toward the 2047 date. 

By 2043, 147 cities — more than half of those studied — will have shifted to a hotter temperature regime that is beyond historical records.

The first U.S. cities to feel that would be Honolulu and Phoenix, followed by San Diego and Orlando, Fla., in 2046. New York and Washington will get new climates around 2047, with Los Angeles, Detroit, Houston, Chicago, Seattle, Austin and Dallas a bit later. 

Mora calculated that the last of the 265 cities to move into their new climate will be Anchorage, Alaska — in 2071. There’s a five-year margin of error on the estimates.

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Online:  

Nature: http://www.nature.com/nature 

Mora lab: http://www.soc.hawaii.edu/mora/