[The findings, some of the first to link climate change to smog, may escalate pressure on Chinese leaders to move more swiftly to shutter steel factories and coal-fired power plants amid rising public anger over smog caused by soot and gases like sulfur dioxide. The research could also push China to assume an even more forceful role in international efforts to curb climate change by reducing carbon emissions, at a time when the United States, under President Trump, appears to be backing away from the issue.]
By Javier C. Hernández
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An extremely polluted December day in
Shengfang, in the northern Chinese province of
Hebei. New research suggests
climate change may be hindering China’s efforts to solve its devastating smog crisis.CreditDamir Sagolj/Reuters
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BEIJING — Chinese
leaders, grappling with some of the world’s worst air pollution, have long
assumed the answer to their woes was gradually reducing the level of
smog-forming chemicals emitted from power plants, steel factories and cars.
But new
research suggests another factor may be hindering China’s efforts to take
control of its devastating smog crisis: climate change.
Changing
weather patterns linked to rising global temperatures have resulted in a dearth
of wind across northern China, according to several recent studies,
exacerbating a wave of severe pollution that has been blamed for millions of
premature deaths. Wind usually helps blow away smog, but changes in weather
patterns in recent decades have left many of China’s most populous cities
poorly ventilated, scientists say.
The
findings, some of the first to link climate change to smog, may escalate
pressure on Chinese leaders to move more swiftly to shutter steel factories and
coal-fired power plants amid rising public anger over smog caused by soot and
gases like sulfur dioxide. The research could also push China to assume an even
more forceful role in international efforts to curb climate change by reducing
carbon emissions, at a time when the United States, under President Trump,
appears to be backing away from the issue.
“Everyone
used to think that controlling smog hinged on reducing regional pollution,”
said Liao Hong, a professor at Nanjing University of Information Science and
Technology and the co-author of a climate change study published this week.
“Now it’s clear that it will require a global effort.”
As
public outrage has grown in China over dirty skies and a rash of respiratory
illnesses linked to smog, Chinese officials have redoubled efforts in recent
years to fight air pollution. They have dispatched teams of police officers to
inspect factories, closed down hundreds of coal-fired power plants and imposed
limits on driving and activities like outdoor barbecuing.
Premier
Li Keqiang, speaking at the annual session of China’s legislature this month,
vowed to “make our skies blue again” and promised to take further steps to
reduce the use of coal.
But even
if Chinese officials push forward with ambitious plans to cut emissions, they
may struggle to offset the effects of climate change, the findings suggest.
Ms.
Liao’s study, which examined data on pollution in Beijing from 2009 to 2016,
predicted that weather conditions associated with severe smog would become
increasingly common in coming decades. The study did not account for possible
reductions in carbon emissions under the 2015 Paris Agreement on climate
change.
Scientists
point to the so-called airpocalypse that fell on Beijing in January 2013 as an
example of the effects of climate change on smog.
During
that episode, Beijing and dozens of other cities in northern China were
shrouded in toxic haze for days. Despite emergency measures to cut emissions,
the concentration of PM2.5, particles of a size that can penetrate the
bloodstream, remained dangerously high.
Researchers
now attribute the resilience of smog during that period to unusually stagnant
air conditions brought on by climate change. The air was the stillest in three
decades during the heavy particulate pollution in 2013, according to a study
published this month in the journal Science Advances.
The
study found that the melting of ice in the Arctic, combined with increased
snowfall in Siberia, contributed to changes in wind patterns across Asia that
winter that failed to clear the air over northern China.
Yuhang
Wang, an atmospheric scientist at Georgia Institute of Technology in Atlanta
who was a co-author of the study, said the results suggested that Chinese officials
would have an especially difficult time curbing air pollution in the winter,
when weather conditions are most conducive to smog and more coal is burned for
heating. The Ministry of Environmental Protection pledged this month to put in
place stricter policies to curb winter air pollution. Beijing is set to host
the Winter Olympics in 2022.
“In the
long run, emission reductions of both pollutants and greenhouse gases are
needed to mitigate the winter haze problem,” Mr. Wang said.
The
effect of climate change on air pollution might extend beyond China. In a study
last year, for example, Mr. Wang found that warmer and drier conditions might
lead to longer stretches of ozone pollution in parts of the southeastern United
States. (Previous studies have also shown a link between climate change and
ozone pollution.)
The
Chinese government has emerged as one of the leading voices on fighting climate
change. As the Trump administration hints that it might move away from
international efforts to cut emissions, environmentalists are looking to China,
the world’s largest emitter of greenhouse gases, to play a leading role in
curbing the use of fossil fuels.
The
government has pledged to go more aggressively after polluters and to cut
excess production in heavy industry. Already, some progress has been made, with
particulate pollution falling nearly 10 percent in the Beijing area over the
past three winters, according to government statistics.
But many
cities, especially in the north, continue to experience severe bouts of smog,
resulting in school closures, traffic accidents and increases in hospital
visits. Enforcement of environmental laws remains lax, and steel capacity
actually rose last year, contributing to a surge in air pollution, a Greenpeace
report found.
The
growing body of research on the links between climate change and air pollution
might serve as a rallying cry for China to take a more aggressive role in
cutting greenhouse gas emissions. But it could also give the government another
excuse for the country’s pollution problems, analysts said.
“In
light of growing local protests against poor air quality, linking this issue
with climate conditions outside of China underscores the fact that the
pollution problem has international sources in addition to local,” said Marc
Lanteigne, a senior lecturer on Chinese defense and security issues at Massey
University in New Zealand.
Environmentalists
said the role of climate change in exacerbating smog was an important finding.
But they underlined the need for local governments to do more to reduce
emissions.
“It
won’t change the overall conclusion that air pollutant emission is the direct
and interior cause for this air pollution problem,” Dong Liansai, a climate and
energy advocate at Greenpeace in Beijing, wrote in an email. “Much more action
is required.”
Owen Guo contributed research.