Human burning of fossil fuels and biofuels for energy use affects global climate change through increasing carbon dioxide (CO2), but also a host of other short-lived non-CO2 effects that are complex and involve impacts that are both warming and cooling. The most important are ozone, a warming greenhouse gas, and fine aerosol particles, including sulfate, black carbon (soot), organic carbon, and nitrate. Most aerosol particles scatter solar radiation back to space and lead to cooling, except for black carbon, which absorbs solar radiation and warms the planet.