Nature World: Wildfires and other types of fires involving plant matter play a much bigger role in climate change and human health than previously thought, according to a recent study. Scientists have long known that biomass burning - burning forests to create agricultural lands, burning savannah as a ritual, slash-and-burn agriculture and wildfires - figures into climate change and public health. But this study, published in the Journal of Geophysical Research: Atmospheres, is the first to measure the degree...