GENEVA, Sept 4 – Faster action on climate change may be possible if nations combine substantial cuts of carbon dioxide emissions alongside accelerated moves across a suite of other greenhouse gases and pollutants.
According to the United Nations Environment Programme, scientists estimate that nearly 50 percent of the emissions causing global warming in the 21st century are from non-CO2 pollutants ranging from black carbon and low-level ozone to methane and nitrogen compounds.
”These ‘climate forcers’ will add to the warming caused by carbon dioxide from the burning of fossil fuels that have been building up since the Industrial Revolution unless their emissions are also addressed,” the report said.
Many of these non-CO2 gases and pollutants need to be addressed in their own right because of growing concern over their impact on human health, agriculture and ecosystems such as forests.
“The time has come for further urgent scientific assessments to determine the precise contribution, impacts and the options for action on ‘non-CO2’ pollutants,” pointed out Achim Steiner, UN Under-Secretary-General and Executive Director of the UN Environment Programme.
Speaking on the margins of the 3rd World Climate Conference, hosted by the World Meteorological Organisation, Mr Steiner said: “There remains some scientific uncertainty about some of these pollutants’ precise contribution to global warming. But a growing body of science points to a potentially significant role.”
“The international community’s over-arching concern must be to seal a convincing deal at the UN climate convention meeting in Copenhagen in less than 100 days time—one that puts the world on track towards swift and significant cuts in carbon dioxide while also providing the funding to assist vulnerable countries and communities to adapt,” said Mr Steiner.
“It is clear that the world must deploy all available means to combat climate change. At this critical juncture, every transformative measure and every substance contributing to climate change should not be overlooked,” he added.
Drew Shindell, a leading climatologist with NASA’s Goddard Institute for Space Studies, and a lecturer in the Department of Earth and Environmental Sciences at Columbia University New York, said: “By including black carbon and tropospheric ozone precursors in climate mitigation strategies, alongside the longer-lived greenhouse gases, development strategies that are both more effective and less costly can be developed”.
“The UN Environment Program should be congratulated for raising these issues and calling for action. The science supporting the strong role of these pollutants in climate change and in damage to human and ecosystem health is becoming increasingly strong,” added the scientist who has also been a reviewer of the assessments of the Intergovernmental Panel on Climate Change (IPCC) and whose science has been used extensively by the panel.
Experts say that in addition their climate contribution, there are compelling and abundant economic and environmental reasons why some of the non-CO2 pollutants need to be addressed under treaties such as the UN Framework Convention on Climate Change and its Kyoto Protocol, the Montreal Protocol on Substances that Deplete the Ozone Layer, and regional health agreements, national air quality strategies and voluntary initiatives.
Mr Steiner cited black carbon from the inefficient burning of biomass and dung for cooking and from diesel engines and coal-fired power stations. Other major sources include the burning of forests, savannas and crop residues.
Black carbon is among a suite of air pollutants linked to 1.6 million to 1.8 million premature deaths annually as a result of indoor exposure and 800,000 as a result of outdoor exposure.
Researchers at the University of Illinois are suggesting that tree growth in the United States is some seven per cent less and that this will climb to up to 17 per cent less by 2100 as a result of low level ozone pollution.
Mr Steiner, speaking less than 100 days before the crucial UN climate convention meeting in Copenhagen, said: “While carbon dioxide can remain in the atmosphere for centuries, some of these other pollutants such as black carbon and ozone have relatively short-lives in terms of days, weeks, months or years”.
“Fast action across a broad front could thus deliver some quick wins on health, food security and wider environmental concerns while also making important contributions to advancing the climate change challenge and the achievement of the poverty-related Millennium Development Goals.”