WASHINGTON (AP) — Starting in about a decade, Kingston,
Jamaica, probably will be off-the-charts hot — permanently. Other places soon
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 never have seen before.
And for dozens of cities, mostly in the tropics, those dates
are a generation or less away.
“This paper is both innovative and sobering,” said Oregon
State University professor Jane Lubchenco, former head of the National Oceanic
and Atmospheric Administration, who was not involved in the study.
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 in the journal Nature, said that by the year 2047,
every year that follows probably will be hotter than that record-setting
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
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
“One can think of this year as a kind of threshold into a
hot new world from which one never goes back,” said Carnegie Institution climate
scientist Chris Field, who was not part of the study. “This is really dramatic.”
Mora forecasts that the unprecedented heat starts in 2020
with Manokwa, Indonesia. Then Kingston, Jamaica.
Within the next two decades, 59 cities will be living in
what essentially is a new climate, including Singapore, Havana, Kuala Lumpur and
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.
Unlike previous research, the study highlights the tropics
more than the polar regions. In the tropics, temperatures don’t vary much, so a
small increase can have large effects on ecosystems, Mora said.
A 3-degree change is not much to polar regions, but is
dramatic in the tropics, which hold most of the Earth’s biodiversity, he said.
The Mora team found that by one measurement — ocean acidity
— Earth already has crossed the threshold into an entirely new regime. That
happened in about 2008, with every year since then more acidic than the old
record, according to study co-author Abby Frazier.
Of the species studied, coral reefs will be the first stuck
in a new climate — around 2030 — and are most vulnerable to climate change, Mora
Judith Curry, a Georgia Institute of Technology climate
scientist who often clashes with mainstream scientists, said she found Mora’s
approach to make more sense than the massive report that recently came out of
the U.N.-sponsored Intergovernmental Panel on Climate Change.
Pennsylvania State University climate scientist Michael Mann
said the research “may actually be presenting an overly rosy scenario when it
comes to how close we are to passing the threshold for dangerous climate
“By some measures, we are already there,” he said.
Copyright 2013 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten or redistributed.