By Damian Carrington, September 23, 2013
Tackling climate change would save millions of lives a year by the end
of the century purely as a result of the decrease in air pollution,
according to a new study.
The study is published as scientists from around the globe gather in
Stockholm to thrash out final details of a landmark assessment of
climate science. Their final report is due to be released this Friday
and will set out projections of wide-ranging impacts of global warming
from droughts to floods to sea-level rise.
The research suggests that the benefits of cuts to air pollution from
curbing fossil-fuel use justify action alone – even without other
climate impacts such as more extreme weather and sea-level rise.
"It is pretty striking that you can make an argument purely on health
grounds to control climate change," says Jason West, at the University
of North Carolina at Chapel Hill, whose work is published in Nature Climate Change.
West's team compared two futures, one in which climate change is
stabilized by aggressive cuts in greenhouse gas emissions and one in
which emissions are not curbed. The scientists then modeled how this
affected air pollutants and the consequent effects on health.
They found that 300,000 to 700,000 premature deaths a year would be
avoided in 2030, 800,000 to 1.8 million in 2050 and 1.4 million to 3
million in 2100. By mid-century, the world's population is expected to
peak at around 9 to 10 billion.
A key finding was that the value of the health benefits delivered by
cutting a tonne of CO2 emissions was $50 to $380, greater than the
projected cost of cutting carbon in the next few decades. The benefits
accrue because of associated pollutants released from burning fossil
It is possible to reduce pollutants in fossil fuel emissions more
cheaply without switching to low carbon sources of power – for example
with scrubbers on coal plants that remove NOx and SOx; or by cars
switching from diesel to petrol – but the authors say it is striking
that the value of health benefits outweigh the costs of cutting carbon.
The benefits were particularly great in China and east Asia,
where the value of health improvements was between 10 and 70 times
greater than the cost of reducing emissions. "The benefits in north
America and Europe are still pretty high, but in east Asia you have a
very high population exposed to very bad air pollution, so there are
lots of opportunities for improvement there," says West.
The research analyzed how cutting emissions from coal-fired power
plants, cars and other sources reduced levels of small pollution
particles which increase heart attacks, strokes and lung cancer and of ozone, which causes respiratory illnesses.
Unlike previous studies, which have tended to focus on specific
countries or regions, the new study took a global perspective. "Air
pollution does not stop at the border," says West. "If China reduces
pollution, people outside of China benefit as some pollution travels
across the Pacific or the other way into south-east Asia."
Another key difference of the new work was including future population
increases and the rising longevity of people, which means they are more
likely to be affected by cardiovascular diseases, rather than dying
young from infectious diseases. The ranges in the estimates of premature
deaths avoided and the economic benefits arise from the relative
uncertainty of how people's health responds to air pollution and the
range of valuations used for lives, with the EPA using a value of $7
million per life, while the European Union uses $2 million per life.
The wider assessment from the Intergovernmental Panel on Climate Change
due on 27 September, its first since 2007, will play a crucial role in
the international negotiations towards a global deal to tackle global
warming in 2015. "Climate change is a long-term problem and the benefits
of any action taken by one country are shared out among all: both of
these things make reaching and an agreement difficult," West says. "But
the air pollution co-benefits are local, tangible and near term, with
air quality improving within weeks. That strengthens the argument for