The kerosene wick lamps that are used for lighting many homes in developing countries have been found to release 20 times more black carbon than previously thought.

The fine particles of soot only linger in the atmosphere for two weeks but one kilogram of black carbon can cause as much warming in that time as 700 kilograms of carbon dioxide circulating for 100 years.

The researchers suggest that replacing kerosene lamps with solar powered LED lamps or simply placing a glass shield around the lamps will reduce the amount of black carbon released.