There are many “natural” and “anthropogenic” (human-induced) factors that contribute to climate change. Climate change has always happened on Earth, which is clearly seen in the geological record; it is the rapid rate and the magnitude of climate change occurring now that is of great concern worldwide. Greenhouse gases in the atmosphere absorb heat radiation. Human activity has increased greenhouse gases in the atmosphere since the Industrial Revolution, leading to more heat retention and an increase in surface temperatures. Atmospheric aerosols alter climate by scattering and absorbing solar and infrared radiation and they may also change the microphysical and chemical properties of clouds. Finally, land-use changes, such as deforestation have led to changes in the amount of sunlight reflected from the ground back into space (the surface albedo).