20.03.19
​
‘Black carbon’ rated as second largest cause of global warming.

Black carbon, a component of particulate matter, is especially dangerous to human health because of its tiny size. But black carbon not only has impacts on human health, it also affects visibility, harms ecosystems, reduces agricultural productivity and exacerbates global warming. Because black carbon absorbs solar energy, it warms the atmosphere. When it falls to earth with precipitation, it darkens the surface of snow and ice, reducing their albedo (the reflecting power of a surface), warming the snow, and hastening melting. The United States is responsible for about 8 percent of global black carbon emissions, with most of it coming from diesel engines, biomass burning, including wildfires, residential heating and industry. Developing countries in Asia, Africa and Latin America emit more than 75 percent of global black carbon emissions, mainly from cookstoves and the burning of solid fuels like coal and wood for heating, which especially affects the health of women and girls. Diesel vehicles and open biomass burning, the largest global source of black carbon, also contribute significant emissions. Snow covered regions are the most vulnerable to the warming effects of black carbon, and any particles reaching them are of concern if they are darker than snow, because they can reduce reflectivity and speed melting. Glaciers are melting in the Andes, the Rocky Mountains, the Canadian Rockies, the Alps, the Himalayas and around the world. As glaciers melt and retreat, the ice melt that during the dry season feeds the rivers that supply irrigation systems will dwindle. The glaciers of the Himalayas and the Tibetan Plateau sustain the rivers of China and India and are critical to the fresh water and food supplies of these two countries. Credit: THE YEARS PROJECT