It keeps heat within the Earth's atmosphere, and it may lead to serious, long-term changes in climate, called global warming. Coal also contains sulphur and other impurities. When burned, they make sulphuric and nitric acids in the atmosphere, which combine with water vapour to form acid precipitation. Acidic rain and snow fall downwind from coal-burning generators. Coal burning creates many tonnes of unburned ash that must be disposed of.
Coal mines create large holes in the landscape.
In many places, groundwater flowing through coal waste creates acid drainage that pollutes streams. What is done to control environmental impact Many different steps reduce environmental problems. These devices remove some of the sulphur dioxide before it leaves the smokestack. Coal can be cleaned before it is burned to remove some of the sulphur. Lower sulphur coals can be substituted, which cause fewer emissions.