Summers in Paris could feel as sweltering as those in Fez, Morocco, by the end of this century if greenhouse gas emissions continue to soar.
By 2100, Toronto could trade its milder summer for a tropical climate like that of Belize City. Cairo, Egypt, could experience summers as scorching as those in Abu Dhabi, which today is one of the hottest places on the planet, according to a new report.
SEE ALSO:An Iranian city hit 129 degrees, one of hottest temperatures ever seen on EarthA new interactive map by Climate Central and the World Meteorological Organization (WMO) shows how many cities could "shift" into warmer temperature zones as rising carbon emissions -- together with growing urban populations and sprawling development -- boost summer temperatures worldwide.
For each city, researchers looked at the projected average summer highs for 2100 and compared them to existing averages in cities today. Their goal is to help people better understand how human-caused global warming will affect our everyday lives.
"It gives people a more visceral feel for how exactly different those [summer] temperatures might be," James Bronzan, a Climate Central research analyst who did the map analysis, said by phone.
The map is based on two global climate scenarios. Under the high-pollution scenario, carbon emissions are left unchecked, and the world carries on with a "business-as-usual" approach. In this case, for example, New York City's present-day average summer highs of 81.8 degrees Fahrenheit would rise to 94 degrees Fahrenheit, on par with Juarez, Mexico today.
But under the "moderate emissions cuts" scenario, New York's average summer highs would still rise to 88.3 degrees Fahrenheit, or Belize City's current average.
New Yorkers cool off during a 2015 heat wave at the Astoria Pool in Queens.Credit: spencer platt/Getty ImagesThe second scenario assumes the world will slash carbon emissions by half between now and 2100. That's roughly the amount that governments have currently pledged to cut under the Paris Climate Agreement. However, countries will have to reduce emissions by much more to achieve the agreement's overarching goal to limit global warming to 2 degrees Celsius, or 3.6 degrees Fahrenheit, above preindustrial levels through 2100.
Both summer temperature scenarios involve a considerable amount of uncertainty, as climate models become less precise when scaled down to the city level, Bronzan noted. And neither offers an exact weather forecast for cities, but rather a projection for how seasonal average temperatures may change.
He added that the cities' average summer highs also don't factor in potential heat waves or record-busting hot days -- both of which are already becoming more common as the planet warms. Studies have shown there is a sharply increased risk of heat extremes as average surface and ocean temperatures climb.
This summer has already ushered in such events in many parts of the world.
A pedestrian walks past a sign displaying the temperature on June 20, 2017 in Phoenix, Arizona.Credit: Ralph freso/Getty ImagesOn June 29, temperatures climbed to 129.2 degrees Fahrenheit in the city of Ahvaz, Iran, which may be not only Iran's hottest temperature on record but also a record high for June in all of mainland Asia. It also may have tied the all-time global heat record, pending further investigation.
In the United States, an unusually wide-reaching and long-lasting heat wave punished at least six states for an entire week. Temperatures were so high near Phoenix and Palm Springs that certain aircraft couldn't fly out of area airports -- offering a preview of what might happen to transportation networks in the coming decades.
While rising summer temperatures affect people well outside of urban areas, researchers said the new Climate Central-WMO map focuses on cities for two key reasons: about half the world's population lives in cities, and city leaders are at the forefront of the fight against climate change.
Bronzan said the project was partially prompted by the swift response to President Donald Trump's June 1 decision to withdraw the U.S. from the Paris agreement. In recent weeks, U.S. mayors, governors, local officials, and business executives have pledged to redouble their own efforts to slash emissions and develop more renewable energy.
"Cities are really taking the lead in thinking about these problems, both from a perspective of mitigating emissions but also in terms of adapting to the problems they're facing," he said. This map, he added, is one more tool for leaders as they confront the challenge.
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