(Image: University of Hawaii/Abby Frazier)
If
global warming continues its trajectory, the year average temperatures
surpass historical norms is just over a few decades away, bringing huge
threats to global biodiversity, a
new study shows.
Researchers
at the University of Hawaii, Manoa created an index based on 39 climate
models used in a dozen countries, and compared that data to the extreme
records from 1860 through 2005.
“We looked at the minimum and maximum values that occurred in that
150-year window and that’s how we set our bounds of recent historical
variability,”
explained Ryan Longman, a doctoral student who worked on the analysis.
The researchers were then able to come up with the "year of climate
departure," and found that the worldwide average for that date was 2047,
meaning that after year after that point will be as warm or warmer. In
other words, it's the date "
when the old maximum average temperatures become the new minimum temperatures."
"The results shocked us," Camilo Mora, the study's lead author, said
in a statement. "Regardless of the scenario, changes will be coming
soon. Within my generation, whatever climate we were used to will be a
thing of the past."
In 2047, Washington, DC and New York City will see temperatures
exceeding historical norms. In Mexico City, that date could come as
soon as 2031. For Kingston, Jamaica, it's just 10 years away. (You can
see more of the findings
in this map.)
While the Arctic and Antarctic have been the subject numerous reports
on the effects of climate change, the new study, shows how small
temperature changes in the Tropics could have massive impacts.
The Smithsonian's
Surprising Science blog explains:
Because the tropics have less variability in temperature to start
with, it takes less of a shift to push temperatures there beyond the
norm. On the other hand, temperatures will indeed surge most in the
Arctic and Antarctic, but there’s already more natural climate
variability at those locales to begin with.
This is a huge concern, because wildlife biodiversity is consistently highest at the tropics, and most of the world’s biodiversity hotspots are located there (tropical rainforests, for instance, are estimated
to cover less than 2 percent of the Earth’s surface area yet contain
roughly 50 percent of its plant and animal species). If, historically,
these ecosystems evolved in the presence of relatively little climatic
biodiversity, it follows that they might be less capable of coping with
swings in temperature and adapting to survive.
"Extinctions are likely to result," warned Ken Caldeira of the
Carnegie Institution for Science's Department of Global Ecology.
Caldeira, who was not involved in the study, added that "Some ecosystems
may be able to adapt, but for others, such as coral reefs, complete
loss of not only individual species but their entire integrity is
likely."
In addition, the study found that oceans already passed their historical extremes in acidification in 2008.
"Scientists have repeatedly warned about climate change and its
likely effects on biodiversity and people," said Mora. "Our study shows
that such changes are already upon us."
Still, Mora is hopeful that the findings can be a catalyst for change.
"These results should not be reason to give up. Rather, they should
encourage us to reduce emissions and slow the rate of climate change,"
stated Mora. "This can buy time for species, ecosystems, and ourselves
to adapt to the coming changes."
The study found that under an "emissions stabilization scenario," the "year of climate departure" could be pushed back—to 2069.
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