Climate Change--It’s Not Just C02

　When 20 years ago governments including Japan brought into force the Montreal Protocol--a treaty to protect the Earth’s ozone layer from chemical attack--few could have foreseen quite how far reaching a decision it would prove.

　The move was explicitly aimed at phasing-out substances such as chloroflurocarbons (CFCs) found in products such a fridges, foams and hairsprays in order to repair the thin gassy-shield that filters out the sun’s harmful, ultra-violet rays.

　In 2010, close to 100 ozone-depleting substances including CFCs will have been fully and finally phased-out globally.

　Without the decisions taken 20 years ago, atmospheric levels of ozone-depleting substances would have increased tenfold by 2050.

　This could have led to up to 20 million more cases of skin cancer and 130 million more cases of eye cataracts, not to speak of damage to human immune systems, wildlife and agriculture.

　But this is only part of the story--over the past two years it has emerged that this treaty has also spared humanity a significant level of climate change as the gases concerned also contribute to global warming.

　Indeed a scientific paper in 2007 calculated the climate mitigation benefits of the ozone treaty as totalling an equivalent of 135 billion tonnes of C02 since 1990 or a delay in global warming of seven to 12 years.

　In that same year governments also agreed to accelerate the freeze and phase-out of CFC replacement substances --Hydrochloflurocarbons (HCFCs)--explicitly for their climate change impacts.

　The maximum benefits here will occur if this goes hand in hand with the introduction of more energy efficient equipment that can work with substances that have low or zero global warming potential.

　The focus is now rapidly shifting to Hydroflurocarbons (HFCs). This year scientists, reporting in the Proceedings of the National Academy of Sciences, suggested that if these became the replacement substances of choice, the climate impacts could be serious.

　The scientists argue that HFC use could climb sharply in the coming years in products such as insulation foams air conditioning units and refrigeration as a new generation of replacements.

　Under a scenario where carbon dioxide emissions are pegged to 450 parts per million HFCs could equal nine Gigatonnes - equivalent to around 45 per cent of total C02 emissions - by 2050 if their growth is unchecked.

　The lessons learnt from the Montreal Protocol may have wider significance.

　Scientists now estimate that somewhere close to 50 per cent of climate change is being caused by gases and pollutants other than C02 including nitrogen compounds, low level ozone formed by pollution and black carbon.

　There remains some scientific uncertainty about some of these pollutants’ precise contribution to warming. But they are certainly playing a significant role.

　Meanwhile, many of these non-C02 gases need to be curbed because of their wider environmental impacts such as those on public health, agriculture and the planet’s multi-trillion dollar ecosystems including forests.

　Black carbon, a component of the soot emissions from diesel engines and the inefficient burning of biomass cooking stoves as one substance to target 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 have also put a wide range of figures on black carbon’s likely climate change contribution ranging from 10 to over 45 per cent of the problem.

　Tropospheric ozone, including ground level ozone, also harms human health and is believed to cause significant damage to crops and ecosystems.

　It occurs from the ground up to 30,000 feet and is generated by substances such as carbon monoxide and nitrogen compounds up to emissions of petroleum products like volatile organic compounds and solvents in the presence of sunlight.

　One recent study suggests that annual losses from the wheat, rice, corn and soya bean crop in China, Japan and the Republic of Korea alone--linked with ground level ozone--may be $5 billion a year.

　Another study by the Massachusetts Institute of Technology estimates that five per cent of cereal production in the United States is lost to ground level ozone and that by 2100 crop yields globally could be cut by 40 per cent.

　One study has suggested that tree growth in the United States is some seven per cent less, climbing to up to 17 per cent by 2100 as a result of ground level ozone pollution. This is particularly troubling as we need healthy forests to help sequester carbon dioxide.

　Researchers estimate that its contribution to the greenhouse effect could range from 15 per cent to 20 per cent which makes it similar to the contribution from methane linked with deforestation and forest degradation.

　Meanwhile nitrogen compounds, emitted from sources including animal wastes, sewage, inefficient use of fertilizers, sewage and vehicle emissions are being linked to a wide range of impacts and not just climate change.

　In terms of black carbon, UNEP has been a partner in the Atmospheric Brown Cloud (ABC) project which has been assessing levels and likely impacts in Asia including Japan.

　In collaboration with scientific community and as part of our mandate on early warning and assessment, we are now extending the scope--including geographically--of this research.

　UNEP has just launched and Integrated Assessment of Black Carbon and Troposperhic Ozone and their role in air pollution and climate change.

　Building on the UNEP ABC project, measuring and monitoring of black carbon and other atmospheric particles is to be extended from the Asia-Pacific region across Africa in order to pin point ‘hot spots’ where reducing emissions can protect human health.

　The work will also include how societies might address these emissions in order to improve public health, crops and ecosystems--and also for the benefits likely to arise in terms of climate change mitigation.

　One study estimates that 26 per cent of black carbon emissions are from stoves for heating and cooking with over 40 per cent of this from wood burning; over 20 per cent from coal; 19 per cent from crop residues and 10 per cent from dung.

　Some companies have developed stoves that cut black carbon emissions by around 70 per cent using passive air flows and better insulation while using 60 per cent less wood--perhaps a mass introduction of such stoves could deliver multiple, Green Economy benefits.

　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.

　Thus fast action across a broad front could deliver some quick wins on health, food security and wider environmental concerns while also making progress on the climate change challenge and the achievement of the poverty-related Millennium Development Goals.

　The international community’s over-arching concern must be to Seal a 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 providing serious funding to assist vulnerable countries and communities to adapt.

　However, it is also becoming clear that the world must also deploy all available means to combat climate change. At this critical juncture, all substances contributing to climate change should be scientifically evaluated and then addressed.