The heating up of the atmosphere because of the greenhouse gases (carbon dioxide and methane) that trap the heat reflected by the Earth, thereby causing an increase in the Earth's temperature, is called global warming or greenhouse effect.
Effects of global warming:
(i) It causes change in the weather and precipitation patterns on the Earth.
(ii) It leads to an increase in methane concentration because of the melting of methane hydrates in polar ice caps and sea floors.