Former Vice President Al Gore has testified before Congress on the dangers posed by global warming. VOA's Dan Robinson reports, the environmentalist and former presidential candidate urged lawmakers to take steps to move the United States toward greater energy efficiency and de-facto compliance with the Kyoto Treaty.

Al Gore's Oscar-winning documentary, An Inconvenient Truth, tracked his efforts around the world to raise international awareness about global warming.

In a statement to a joint hearing of two congressional committees, he returned to the theme of his film, saying there is irrefutable evidence that the Earth is experiencing an unprecedented period of climate change.

Gore says the United States must take the lead, and lawmakers must summon the courage, to take steps that will help reverse the process, so future generations will not ask this question.

"What in God's name were they doing? Didn't they realize that four times in 15 years the entire scientific community in this world issued unanimous reports calling on them to act? What was wrong with them? Were they too blinded and numbed by the business of political life, or daily life, to take a deep breath and look at the reality of what we are facing?," said Gore.

"Did they think it was perfectly all right to keep dumping 70 million tons every single time of global warming pollution into this atmosphere? Did they think all the scientists were wrong?," he continued.

Gore cited recent studies saying that global warming may be worse than previously thought, and that the Arctic ice cap is melting more rapidly than previously predicted, and could disappear in as little as 34 years.

"This problem is burning a hole at the top of the world in the ice cover that is one of the principal ways that our planet cools itself. If it goes, it will not come back in any time scale relevant to the human species," said former vice president.

Gore appeared at a time when majority Democrats have made the issue of climate change a key part of their agenda.

House Speaker Nancy Pelosi created a special committee on climate change and is encouraging legislation that would promote reduction in greenhouse gas emissions and encourage use of renewable fuels.

Republicans took the opportunity to renew criticisms of several aspects of Gore's film, and question conclusions he drew from scientific findings.

Congressman Joe Barton took aim at two of Gore's recommendations.

"Some of your ideas though, Mr. Vice President, I think are just flawed," said Joe Barton. "Your suggestion of a carbon tax is something that would harm our competitiveness, raise costs to American families, export jobs and actually do very little to improve our environment."

"Likewise a Kyoto-style cap and trade system for carbon dioxide will mainly increase the price of electricity while providing few if any environmental benefits," he added.

Gore urged Congress to pass legislation to encourage energy efficiency, including tighter standards for automobiles, and bar the construction of any new coal-fired power plants not capable of capturing carbon dioxide (greenhouse gases) that would otherwise be released into the atmosphere.

He also advocates steps to bring the United States into effective compliance with the existing Kyoto treaty, and says the effective date of a new treaty to succeed it should be moved up to 2010.

Gore's appearances in House and Senate committees marked his first return to the Capitol since 2001, when he presided over a congressional session that certified the victory of George W. Bush based on electoral college votes after the contested 2000 presidential election.

Although he has said he has no intention of running for president again, he still scores high in public opinion polls and has spoken out strongly against Bush administration policies in Iraq and other issues.