Only
one tipping point? Only then? I suspect reality might trump this vision.
Climate
change tipping point revealed by study published in Nature
THE
dreaded climate-change "tipping point", when changes to
weather patterns will become irreversible, has been identified. And
it is terrifying.
10
October, 2013
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.
Australia
will not be far behind, with dates ranging from 2038 in Sydney to
2049 in Adelaide.
Virtually
the whole world will have changed by 2050.
A
new study on global warming, published in the journal Nature,
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.
For
dozens of cities, mostly in the tropics, those dates are a generation
or less away.
This
map from the journal Nature shows major cities and the years they
will hit the tipping point. Source: Supplied
"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 past 150 years.
For
example, the world as a whole had its hottest year on record in 2005.
The new study 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."
A
date of 2047 for whole-world change (although a handful of cities are
outside that range) 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.
"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 is essentially a new climate, including
Singapore, Havana, Kuala Lumpur and Mexico City.
By
2043, 147 cities - more than half of those studied - will have
shifted to a higher temperature regime that is beyond historical
records.
The
first US cities to feel that would be Honolulu and Phoenix, followed
by San Diego and Orlando, Florida, 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.
This
is not the Blue Mountains or the Adelaide Hills, but Russia, where
bushfires accompanied that country’s worst heatwave in 2010.
Temperature records have been set around in the world in recent
years. AFP PHOTO / ANDREY SMIRNOV Source: AFP
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, he said. A 3C
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 has
already 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 said.
Pennsylvania
State University climate scientist Michael Mann said the research
"may be actually presenting an overly rosy scenario when it
comes to how close we are to passing the threshold for dangerous
climate impacts."
"By
some measures, we are already there," he said.
THE
TIPPING POINTS
Melbourne
2045
Sydney
2038
Perth
2042
Adelaide
2049
Manokwari
(West Papua) 2020
Ngerulmud
(Palau) 2023
Port-au-Prince
2025
Jakarta
2029
Durban
2035
Cairo
2036
Tokyo
2041
Beijing
2046
New
York 2047
Los
Angeles 2048
Toronto
2049
Paris
2054
Brussels
2056
London
2056
Moscow
2063
Anchorage
2071
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