Human activity is not solely responsible for climate change. It can occur due to natural causes as well. Large volumes of sulphur dioxide, ash, water vapor and dust escape into the atmosphere when a volcano erupts. Volcanoes also produce aerosols which reflect solar energy back into space. This cools the atmosphere. However, although volcanoes produce CO2 and greenhouse gases it is minor when compared to what we humans emit into the atmosphere. Changes in the Earth’s orbit and changes to the ocean’s currents are also natural causes that cause climate change.
Feedback Form for WebCT Students: Click icon to the left for a form on which you can record your understanding of this material. (Password protected.) For further reading, we suggest "The Declining Middle," an essay in the Atlantic Monthly by Bob Kuttner. Kuttner's 1983 essay analyzes the effects of various economic changes in American life. (It is interesting to see, now, how much of what he said about these effects has come to be true.) For a lengthy and complex article that defines the causes of homosexuality, read Chandler Burr's "Homosexuality and Biology." Burr's article ( Atlantic , 1997) is also an excellent example of an essay that defines .