|Climate scientist Veerabhadran Ramanathan
Protecting the near-term climate is central to significantly cutting the
risk of "amplified global climate change" linked with rapid and
extensive loss of Arctic ice on both the land and at sea, said
assessment authors including Veerabhadran Ramanathan, a climate and
atmospheric scientist at Scripps Institution of Oceanography, UC San
Fast action might also reduce losses of mountain glaciers linked in part
with black carbon deposits while reducing projected warming by two
thirds in the Arctic over the coming decades by two thirds.
"The proposed measures for reducing black carbon, methane and ozone levels in the atmosphere significantly increase our chances to keep global warming below dangerous levels during this century," said Ramanathan, a vice chair of the assessment team. "Some of the measures, such as improved cookstove technologies and cutting down diesel emissions of black carbon also have the fantastic co-benefit of reducing one million or more fatalities every year among women and children."
The findings, released today (June 15) in Bonn, Germany, during a meeting of the
UN Framework Convention on Climate Change (UNFCCC) have been compiled by
an international team of more than 50 researchers chaired by Drew
Shindell of the National Aeronautics and Space Administration (NASA).
Ramanathan is organizing a related briefing today in Washington, D.C.,
for several federal agencies on how to reduce emissions of global
warming pollutants such as carbon dioxide, black carbon and ozone and
prevent human deaths from traditional biomass burning cook stoves in
The scientists behind the assessment, coordinated by the United Nations
Environment Programme (UNEP) and the World Meteorological Organization
(WMO), whose Secretariat is provided by the Stockholm Environment
Institute (SEI), also point to numerous public health and food security
opportunities above and beyond those linked with tackling climate
Big cuts in emissions of black carbon will improve respiratory health and reduce hospital admissions and days lost at work due to sickness. Close
to 2.5 million premature deaths from outdoor air pollution could on
average be avoided annually worldwide by 2030 with many of those lives
saved being in Asia, it is estimated. Big cuts in ground level ozone
could also contribute to reduced crop damage equal to between 1 to 4 percent of the annual global maize, rice, soybean and wheat
Cutting these so-called 'short-lived climate forcers' can have immediate
climate, health and agricultural benefits, the report concludes. This
is because, unlike carbon dioxide (CO2) which can remain in the
atmosphere for centuries, black carbon for example persists only for
days or weeks.
The researchers, however, also underline the fact that while fast action on black carbon and ground-level ozone could play a key role in limiting near-term climate, immediate and sustained action to cut back CO2 is crucial if temperature rises are to be limited over the long-term.
It is the combination of action on short-lived climate forcers and
long-lived greenhouse gases which improves the chances of keeping below
the 2-degree target throughout the 21st century.
Achim Steiner, UN under-secretary general and UNEP executive director, said: "There are now clear, powerful, abundant and compelling reasons to reduce levels of pollutants such as black carbon and tropospheric ozone along with methane: their growing contribution to climate change being just one of them.
"This assessment underlines how the science of short lived climate
forcers has evolved to a level of maturity that now requires and
requests a robust policy response by nations. The experts spotlight how a
small number of emission reduction measures — targeting, for example,
recovery of methane in the coal, oil and gas sectors through to the
provision of cleaner burning cook stoves; particle traps for diesel
vehicles and the banning of open burning of agricultural wastes — offer
dramatic public health, agricultural, economic and environmental
benefits," he added.
The UNEP/WMO Integrated Assessment of Black Carbon and Tropospheric
Ozone suggests that action could be catalyzed through not only the UN
climate convention process but also via, for example, strengthening
existing national and regional air quality agreements.
Michel Jarraud, director general of the WMO, said: "Combating climate
change will not be possible unless there are significant reductions of
the main greenhouse gas, CO2. However, over recent years it has become
clear that a range of other pollutants such as black carbon and
tropospheric ozone are aggravating that challenge. This report
highlights how improved scientific understanding of the role of other
pollutants can inform policy decisions related to climate change
Drew Shindell of NASA's Goddard Institute for Space Studies said: "This report has brought clarity to the complexity of the heating and cooling effects of a range of pollutants and uses the science to show that there are clear and concrete measures that can be undertaken to help protect the global climate in the short to medium term. Perhaps the most intriguing link is between emissions of methane and the formation of tropospheric ozone. Methane is a powerful greenhouse gas in its own right, but it has emerged that it is also triggering a great deal more global warming by contributing to the formation of significant levels of ground level ozone-indeed more than was previously supposed. The win-win here for limiting climate change and improving air quality is self-evident and the ways to achieve it have become far clearer as a result of this assessment."
Today (June 15) the government of Sweden announced support for a comprehensive and
forward-looking policy assessment to assist governments on the next
steps towards fast action on short-lived climate forcers (SLCFs). This
is in line with Sweden's strategy on SLCFs and its policy to integrate
climate change and air pollution policies.
The work, to be coordinated by UNEP, is expected to be ready in advance
of the next Climate Convention meeting scheduled later in the year in
Durban, South Africa.
Black carbon is a major component of soot and is formed from the
incomplete combustion of fossil fuels, wood and biomass. Key sources
include emissions from cars and trucks, cookstoves, forest fires and
some industrial facilities. It affects the climate by intercepting and
absorbing sunlight and darkens snow and ice when deposited, while also
influencing cloud formation. It also is a health hazard.
Tropospheric ozone is a major component of urban smog and is a powerful
greenhouse gas and air pollutant harmful to human health and ecosystems.
The threefold increase in concentrations in the northern hemisphere in
the past 100 years has made it the third most important global
Tropospheric ozone is formed from other gases including methane — itself a potent greenhouse gas emitted from sources such as waste tips, livestock and the oil and gas industry.
About Scripps Institution of Oceanography
Scripps Institution of Oceanography at University of California, San Diego, is one of the oldest, largest and most important centers for global science research and education in the world. Now in its second century of discovery, the scientific scope of the institution has grown to include biological, physical, chemical, geological, geophysical and atmospheric studies of the earth as a system. Hundreds of research programs covering a wide range of scientific areas are under way today in 65 countries. The institution has a staff of about 1,400, and annual expenditures of approximately $170 million from federal, state and private sources. Scripps operates robotic networks, and one of the largest U.S. academic fleets with four oceanographic research ships and one research platform for worldwide exploration. Birch Aquarium at Scripps serves as the interpretive center of the institution and showcases Scripps research and a diverse array of marine life through exhibits and programming for more than 415,000 visitors each year. Learn more at scripps.ucsd.edu.
About UC San Diego
Fifty years ago, the founders of the University of California, San Diego, had one criterion for the campus: It must be distinctive. Since then, UC San Diego has achieved the extraordinary in education, research and innovation. Sixteen Nobel laureates have taught on campus; stellar faculty members have been awarded Fields Medals, Pulitzer Prizes, MacArthur Fellowships and many other honors. UC San Diego — recognized as one of the top 10 public universities by U.S. News & World Report and named by the Washington Monthly as number one in the nation in rankings measuring "what colleges are doing for the country" — is widely acknowledged for its local impact, national influence and global reach. UC San Diego is celebrating 50 years of visionaries, innovators and overachievers. 50th.ucsd.edu