Heat Will Likely Soar to Record Levels in Next 5
Years, New Analysis Says
By Brad
Plumer
May 17,
2023
Updated
3:07 p.m. ET
https://www.nytimes.com/2023/05/17/climate/record-heat-forecast.html
Global
temperatures are likely to soar to record highs over the next five years,
driven by human-caused warming and a climate pattern known as El Niño,
forecasters at the World Meteorological Organization said on Wednesday.
The record
for Earth’s hottest year was set in 2016. There is a 98 percent chance that at
least one of the next five years will exceed that, the forecasters said, while
the average from 2023 to ’27 will almost certainly be the warmest for a
five-year period ever recorded.
“This will
have far-reaching repercussions for health, food security, water management and
the environment,” said Petteri Taalas, the secretary general of the
meteorological organization. “We need to be prepared.”
ImageA
woman in a red dress walking on a crosswalk while holding white piece of
clothing over her head to shield herself from the sun.
A hot day
in Manhattan in the summer of 2016, which is currently the warmest year on
record.Credit...Bryan Thomas for The New York Times
Why It Matters: Every fraction of a degree brings new
risks.
Even small
increases in warming can exacerbate the dangers from heat waves, wildfires,
drought and other calamities, scientists say. Elevated global temperatures in
2021 helped fuel a heat wave in the Pacific Northwest that shattered local
records and killed hundreds of people.
El Niño
conditions can cause further turmoil by shifting global precipitation patterns.
The meteorological organization said it expected increased summer rainfall over
the next five years in places like Northern Europe and the Sahel in sub-Saharan
Africa and reduced rainfall in the Amazon and parts of Australia.
El Niño and La Niña, Explained
The
organization reported that there is also a two thirds chance that one of the
next five years could be 1.5 degrees Celsius, or 2.7 degrees Fahrenheit, hotter
than the 19th-century average.
That does
not mean that the world will have officially breached the aspirational goal in
the Paris climate agreement of holding global warming to 1.5 degrees Celsius.
When scientists talk about that temperature goal, they generally mean a
longer-term average over, say, two decades in order to root out the influence
of natural variability.
Many world
leaders have insisted on the 1.5-degree limit to keep the risks of climate
change to tolerable levels. But nations have delayed so long in making the
monumental changes necessary to achieve this goal, such as drastically cutting
fossil-fuel emissions, that scientists now think the world will probably exceed
that threshold around the early 2030s.
Background: La Niña, a cooling influence, is on the
way out.
Global
average temperatures have already increased roughly 1.1 degrees Celsius since
the 19th century, largely because humans keep burning fossil fuels and pumping
heat-trapping gases like carbon dioxide into the atmosphere.
But while
that overall upward trend is clear, global temperatures can bounce up and down
a bit from year to year because of natural variability. For instance, a
cyclical phenomenon in the Pacific Ocean, the El Niño-Southern Oscillation,
causes year-to-year fluctuations by shifting heat in and out of deeper ocean
layers. Global surface temperatures tend to be somewhat cooler during La Niña
years and somewhat hotter during El Niño years.
The last
record hot year, 2016, was an El Niño year. By contrast, La Niña conditions
have dominated for much of the past three years: while they’ve been unusually
warm, they were still slightly below 2016 levels. Now, scientists are expecting
El Niño conditions to return later this summer. When combined with steadily
rising levels of greenhouse gases in the atmosphere, that will most likely
cause temperatures to accelerate to new highs.
Brad Plumer
is a climate reporter specializing in policy and technology efforts to cut
carbon dioxide emissions. At The Times, he has also covered international
climate talks and the changing energy landscape in the United States. @bradplumer


Sem comentários:
Enviar um comentário