March 21 (Bloomberg) -- Former Vice President Al Gore, who organized the first congressional hearing on climate change almost three decades ago, returned to Capitol Hill to urge lawmakers to address a ``planetary emergency'' by reversing the growth of emissions that are blamed for global warming.

``The consequences of inaction would be devastating to both the environment and the economy,'' Gore, a Tennessee Democrat, said today in remarks to a joint hearing of the energy and science committees in the House of Representatives. He also testified to a Senate panel.

Gore said lawmakers should pass legislation that would halt carbon dioxide emissions at current levels, and require a 90 percent cut in pollution by 2050. He called for a moratorium on construction of any new coal-fired power plants that can't capture and store their greenhouse gas emissions and a tax on carbon emissions.

Democratic leaders in Congress have said that passing legislation to address the threat of global warming is a top priority. President George W. Bush and other Republicans oppose a mandatory limit on carbon dioxide emitted from cars, power plants and other human activities, saying that it would hurt the economy.

``As we increase regulation, we force jobs out of this country,'' Illinois Republican Representative Dennis Hastert, the former House speaker, said today.

Fuel-Economy Standards

Gore, who has lectured worldwide about the dangers of global warming, told lawmakers he backs more stringent auto fuel-economy standards and a new international climate change treaty spearheaded by the U.S. that would start in 2010. The current Kyoto Protocol, an international agreement to cut greenhouse gases, will expire in 2012. The U.S., the world's biggest emitter of carbon, isn't part of the accord.

Gore, citing scientists such as the U.S. government's top climatologist, James Hansen, said the U.S. must act soon if it hopes to avoid the most damaging affects of global climate change, including more powerful hurricanes, devastating droughts and rising coastal waters.

One global warming study warns that the Arctic ice cap might melt completely in as little as 34 years, he said.

``This problem is burning a hole at the top of the world in the ice cover that is one of the principle ways that our planet cools itself,'' Gore, a former representative and senator, told the House committees. ``If it goes, it won't come back on any time scale relevant to the human species.''

`All-Out Assault'

Republican Representative Ralph Hall of Texas said Gore's testimony is part of an ``all-out assault on all forms of fossil fuels.''

``If we allow this attack on energy to go unanswered -- and have it result in lessening our domestic reliance on fossil fuels -- we will force a reliance on OPEC from a dangerous 60 percent to a recklessly dangerous and likely 80 percent of our total energy supply,'' Hall said.

An increasing number of companies, including General Electric Co., say they want national carbon limits so they know how to proceed with their business plans and so they can profit from the development of new, ``clean'' technologies. Yet, officials at companies such as Atlanta-based Southern Co., the largest U.S. electricity generator, oppose a cap and say that technology to capture and store carbon emissions isn't commercially viable.

Barton Objects

Representative Joe Barton of Texas, the ranking Republican member of the House Energy and Commerce Committee, said many of Gore's suggestions are flawed.

A carbon tax would raise energy prices and cost jobs while ``providing few if any environmental benefits,'' Barton said.

Gore said he isn't calling for higher taxes. Instead, he seeks a reduction in employment taxes that's offset by a levy on greenhouse-gas emissions.

``I fully understand this is considered politically impossible, but part of our challenge is to expand the limits of what's possible,'' Gore said.

Gore said he supports both a carbon tax and a ``cap and trade'' program, which would allow polluters emitting less carbon than permitted to sell or trade their excess pollution permits to others.

``As a practical political matter, some would say'' do only one, Gore said. ``I think the most effective approach is to do both.''

Caused By Humans

A United Nations panel of scientists said this year that global warming is ``very likely'' caused by humans and that world temperatures and sea levels will increase by the end of the century.

Senator James Inhofe of Oklahoma, the ranking Republican on the Senate Environment and Public Works Committee, attacked the science behind some of Gore's key claims, including a warning that sea levels may rise by 20 feet due to melting in eastern Antarctica.

``When the debate is balanced, skeptics win, alarmists lose,'' said Inhofe.

Gore, to illustrate what he says is increasing public concern about global warming, brought with him boxes filled with 516,000 postcards from people who say they want the government to take action.

Gore, 58, has been enjoying a popularity surge in the past year as ``An Inconvenient Truth,'' a documentary film featuring the former vice president lecturing about the dangers of global warming, won commercial and critical praise, including two Academy Awards.

Nobel Nomination

He's also been nominated by two Norwegian lawmakers for a Nobel Peace Prize in recognition of his global warming work.

Such accolades have stirred speculation that Gore might make another bid for the White House. Gore, who lost to Republican Bush in 2000, has said he has no plans to run for president.

Democratic Senator Hillary Clinton, who is making a bid for the White House next year, praised Gore's efforts at today's Senate hearing and also asked the fellow Democrat for more information about his proposal to establish a ``carbon neutral'' mortgage association.

Gore said such an entity would enable property buyers to amortize the cost of equipping homes or buildings with the most efficient energy saving features.

The former vice president also urged Congress to set a date to ban the use of traditional, or incandescent, light bulbs in favor of more energy efficient lighting. ``Give industry time to deal with the change,'' he said today. ``They'll do it.''

To contact the reporter on this story: Kim Chipman in Washington at kchipman@bloomberg.net.

Last Updated: March 21, 2007 19:15 EDT