Climate of the earth keeps on changing in a natural cycle but the scientists are worried because the speed of these changes in the climate has been accelerated due to the activities of human beings. This activity saw an unprecedented rise after the industrial revolution. There are natural causes of climate change like the continental drift, ocean currents, volcanoes, meteorites and comets and the earth’s tilt.

The scientists are concerned with the human causes which contribute hugely to the rise in the green house gases in the atmosphere. Increasing use of fossil fuels like oil, natural gas and coal is responsible for about ¾ of the carbon dioxide emissions as well as one fifth of the methane released in the atmosphere.