In uninhabited regions, the main causes are likely to be increased ultraviolet light penetrating through the Earth's damaged ozone shield, and global warming. Coral bleaching occurs when water temperatures rise, and coral bleaching has been increasing worldwide since the 1970s as Earth's temperature has risen most steeply. Furthermore, recent work shows that, as the carbon dioxide content of the atmosphere increases, so does the carbon dioxide content of ocean water. The future for coral reefs looks grim. The coral reefs of southeast Asia provide homes for one-quarter of the world's fish species.
Similar trends are observable in Canada, Japan, Russia, China, and Australia.
The annual number of intense storms over the North Atlantic and the North Pacific has doubled since 1900. There have been more, and longer-lasting, El Nino events since the 1970s. El Nino is a huge but localized warming in the eastern Pacific Ocean that gives rise to violent storms along the U.S. Pacific coast, devastating droughts in Africa and Australia, and often a failure of the monsoon rains in Asia. New computer models have been able to mimic past climate changes, and they predict future warming of the atmosphere. Skeptics used to say that computer models had done such a poor job of mimicking past events that their predictive ability must also be flawed.