Page 111

Photo Credit: UN Photo-Mark GartenLimiting the near-term rise in global mean temperatures is only one of several goals of an SLCP strategy, however. Methane is not only a very powerful greenhouse gas but is also a chemically reactive one, leading to ozone formation in the lower atmosphere. Ozone in the lower atmosphere is likewise a greenhouse gas, and is toxic to both humans and ecosystems. Hence reductions of methane bring benefits to human and ecosystem health along with mitigating climate change. Products of incomplete combustion include black carbon (soot), a highly potent warming agent owing to its strong absorption of sunlight, organic carbon compounds with a more complex mixture of absorption and reflectivity, and carbon monoxide, another gas leading to ozone formation. Carefully selected control measures can lead to a net climate benefit at the global scale, but their impacts at local to regional scales are even greater. Black and organic carbon haze can alter weather patterns, disrupting large-scale features such as the Asian Monsoon and the tropical wet and dry seasons. Particulate haze due “ REDUCTIONS IN PRODUCTS OF INCOMPLETE COMBUSTION THAT INFLUENCE THE ARCTIC OR THE HIMALAYAN/TIBETAN REGION CAN BE ESPECIALLY IMPORTANT FOR BOTH CLIMATE AND REGIONAL WATER SUPPLIES”Below: Black carbon increases the melting rate of snow and ice in the Arcticto North American and European pollution contributed to drought in the Sahel during the 1980s, for example. These hazes can increase the likelihood of extreme events such as local flooding as well. Black carbon also has an outsized effect when falling on snow or ice as it darkens those surfaces, causing them to melt much more rapidly. Hence reductions in products of incomplete combustion that influence the Arctic or the Himalayan/Tibetan region can be especially important for both climate and regional water supplies. Additionally, black and organic carbon constitute a substantial portion of particulate matter with a diameter smaller than 2.5 microns (PM2.5). These particles are so small that they can be inhaled deeply into the lungs, where they contribute to respiratory and cardiovascular diseases. In 2012 the World Health Organization declared outdoor air pollution, consisting of PM2.5 and ozone, to be the leading environmental cause of premature death worldwide claiming more than 3 million victims per year. The United Nations GLOBAL VOICES 111