Top of PageWhat causes climate change?
Changes in climate can be caused by natural events and processes and by human influences. However, since the industrial revolution began, about 150 years ago, climate change due to human influences has increased significantly. Key human influences include changes in greenhouse gas concentrations, ozone depletion, air pollution and alterations in land use. Most of these human influences alter the composition of the atmosphere and thereby affect the amount of heat energy escaping to space, although some also change the amount of sunlight reflected to space. The build-up of greenhouse gases in the atmosphere is the primary cause for concern about climate change over the coming century. Key natural factors include changes in the intensity of sunlight reaching the earth and in the concentration of volcanic dust, which reflects sunlight back to space. Both of these factors alter the amount of sunlight that is absorbed by the earth’s climate system.
