October 14, 2005

Past Climate Change Supports Current Global Warming

Ancient plankton show tiny temperature fluctuations can have big effects, study says

Some of the strongest evidence yet of a direct link between tropical warmth and higher levels of greenhouse gases is found in past climate records, U.S. researchers say.

The current steady increase in tropical temperatures caused by global warming could have a major impact on global climate and result in more destructive storms like Hurricane Katrina, according to a team at the University of California, Santa Barbara.

"The relationship between tropical climate and greenhouse gases is particularly critical because tropical regions receive the highest proportion of solar output and act as a heat engine for the rest of the Earth," study co-author David Lea, professor in the university's department of Earth science and the Marine Science Institute, explained in a prepared statement.

The UCSB team analyzed the chemical composition of ancient fossil plankton shells from a deep sea core obtained in the equatorial Pacific Ocean, to get information about past climate conditions. The evidence from that analysis supports the link between increased greenhouse gases caused by fossil fuel combustion and a 1- to 2-degree Fahrenheit rise in tropical sea surface temperature over the last 50 years.

The study appears this week in Science Express, the online publication of the journal Science.

More information

The U.S. Environmental Protection Agency has more about the health effects of global warming (http://yosemite.epa.gov ).