Former U.S. Vice President Al Gore on Friday urged scientists to exert influence on global climate change, in a special address in Chicago.

In his speech at the American Association for the Advancement of Science(AAAS) annual meeting in Chicago, Gore focused on global warming, its impact on human survival and clean energy, echoing the theme of this year's AAAS convention: "Our Planet and Its Life: Origins and Futures."

He reviewed global warming phenomenon and weather-related disasters in the last century. The address was open to AAAS registrants and press.

"We as a species must make a decision," said Gore. "And I believe in my heart that we do have the capacity to make a change."

A lot of photographs, charts, animation slides and videos were showed during his address to illustrate the consequences of the "climate crisis," which Gore addressed together with the financial crisis and the U.S. "national security crisis."

In one video recorded in the Arctic, a researcher screamed when a colleague ignited a large cloud of methane gas that Gore said was bubbling up as a result of the melting ice cap. Another photo, pictured just a few days ago in Australia, showed a volunteer watering a koala after the great fire.

Gore also called for the use of clean energy instead of carbon-based fuels such as coal, by showing several "Repower America" video clips.

Gore encouraged the "world of science" and "the world of politics" to work together to response to the climate crisis. He called for the scientist to deliver the sense of emergency to their colleagues, networks, and policy makers.

"For those of you who haven't communicated, there is no time to sit back," concluded Gore.

(Xinhua News Agency Feburary 14, 2009)