Black carbon or “soot” is the second leading cause of global warming and is estimated to be responsible for ~20% of the global warming and ~40% of glacier melting that has occurred to date. Black carbon also has serious health effects, including asthma and lung cancer.
Because black carbon remains in the atmosphere for only about two weeks on average, control of black carbon emissions has been identified as the most cost effective way for slowing climate change in the near future.