The United States Congress has been told to ignore President Barack Obama's plan to place limits on carbon emissions because climate change does not exist.

"The right response to the non-problem of global warming is to have the courage to do nothing," said British aristocrat Lord Christopher Walter Monckton, a leading proponent of the 'climate change is myth' movement.

The Third Viscount Monckton of Brenchley - who was an adviser to former British prime minister Margaret Thatcher - argued before the Energy and Environment Subcommittee that for 14 years "there has been no statistically significant global warming."

The House hearing - titled Adaptation Policies in Climate Legislation - discussed ways to address Mr Obama's cap-and-trade proposal in his $US 3.6 trillion ($5.1 trillion) budget plan, presented to Congress in February.

Mr Obama's proposal would limit emissions of greenhouse gases for manufacturers, and permit companies to trade the right to pollute to other firms - a similar cap-and-trade system to the European model.

The moves are now subject of intense political opposition in Congress, notably from politicians representing US states heavily invested in energy production through fossil fuels.

"Adaptation is at present unnecessary," said Lord Monkton at the hearing.

"Mitigation is always unnecessary - it is also disproportionately expensive. Green jobs are the new euphemism for mass unemployment."

Addressing the hearing on the "balanced Biblical view" for environment and development issues, Pastor Calvin Beisner - national spokesman for the Cornwall Alliance, a coalition of clergy, theologians and religious leaders - questioned proposed efforts to combat climate change.

"I am convinced that policies meant to reduce alleged carbon dioxide-induced global warming will be destructive," he said.

"The Biblical world view sees Earth and its ecosystems as the effect of a wise God's creation and ... therefore robust, resilient, and self-regulating, like the product of any good engineer."

Congressman Joe Barton - from the oil-rich state of Texas - maintained "mankind always adapts" and "adaptation to shifts in temperature is not that difficult."

'Threats are mounting'

Facing down the non-believers, an array of Government agency representatives and environmental organisations described the mounting threats to human life from devastating climate change - including rising sea levels, soaring temperatures and increasingly violent weather phenomena.

Tom Karl - director of the National Climatic Data Center at the National Oceanic and Atmospheric Administration - stressed mitigation would not suffice.

"While increased mitigation measures will likely reduce the need for future adaptation, the United States and the world will continue to experience changing climate conditions and resulting impacts," he said.

The National Wildlife Federation's president Larry Schweiger urged politicians to tackle climate change, saying the United States "must invest now in safeguarding the natural world from the inevitable impacts of global warming".

Recalling the report from the Nobel Prize-winning UN Intergovernmental Panel on Climate Change, Mr Schweiger warned due to cataclysmic climate change, "in the lifetime of a child born today, 20 to 30 per cent of the world's plant and animal species will be on the brink of extinction if we don't take action now."

Many Republicans in Congress fear a market-based mechanism to cut carbon emissions may hit the competitiveness of US firms and products on global markets, particularly while China and India refuse to make concessions in tandem.

Source: Agence France-Presse