Washington - Democratic lawmakers on Friday released a watered-down bill to help the United States combat climate change, easing some targets to placate some moderate members of the centre- left party worried about the economic impact. The compromise preserves the key elements of an earlier draft including a controversial cap-and-trade system, and was welcomed by most environmental groups who hope the new version will have a better chance of becoming law in the United States.
The legislation was introduced in the Energy and Commerce Committee of the House of Representatives - the first step in a process that many expect could last into next year.
Other countries hope a deal in Congress could pave the way for a wider international agreement in December, when governments in Copenhagen convene for a key climate conference.
Addressing climate change has been highly controversial in the United States, with many centre-right Republicans and some Democratic lawmakers arguing that aggressive curbs to pollution will harm an already struggling economy.
Some lawmakers are pressing for major emerging countries to tackle their emissions first. The US and China are the world's largest polluters, together making up about 50 per cent of global emissions.
US President Barack Obama has called for stiffer targets to curb US pollution and reversed a series of environmental policies from his predecessor George W Bush. Obama supports placing mandatory limits on companies in a bid to reduce greenhouse-gas emissions that are blamed for causing global warming.
The deal reached this week among Democrats relaxes requirements of the central cap-and-trade initiative, which would set a nationwide limit on pollution levels but allow dirtier and cleaner companies to trade their allowances.
The new bill allows about 15 per cent of the allowances to be handed out for free to polluting firms until at least 2025, placating some Democratic lawmakers from energy-intensive states.
A number of environmental groups said they remained behind the legislation, but Greenpeace issued a statement saying it could no longer support the effort.
"While science clearly tells us that only dramatic action can prevent global warming and its catastrophic impacts, this bill has fallen prey to political infighting and industry pressure," Phil Radford, US Greenpeace executive director, said in a statement.
