The possibility of wide-reaching US environmental legislation took another leap forward this week after a bill was voted through a Senate committee that would see drastic cuts in carbon emissions over the next few decades.

The Climate Security Act 2007, sponsored by Senators John Warner and Joseph Lieberman, would make sweeping changes to the way that America manages its greenhouse gas output.

Under the legislation, the US would freeze greenhouse gas emissions in 2012 and then reduce them by 62 per cent through to 2050. The reduction would be handled using a "cap-and-trade" carbon trading system similar to that already operated in Europe, under which companies would trade the right to produce emissions above a set limit through a national exchange.

The bill is particularly significant given that the US opted out of the Kyoto Protocol, which Australia's new government finally ratified this week. Kyoto calls for an international cap-and-trade system to curb greenhouse emissions.

"Kyoto was roundly rejected in the US but I think the debate is focused on what we do post-Kyoto," said Tobyn Anderson, vice president at DC-based lobbyist Lighthouse Consulting.

Lighthouse consults for the US Climate Action Partnership, a group of US businesses lobbying for greenhouse gas reductions, which Tobyn says has adopted no official stance on the legislation. "The White House hasn't yet embraced a mandatory programme, but the broad consensus in congress is that we do need a mandatory programme post-2012," he added.

The bill still has a long way to go before it becomes law in the US. The senate has to debate the bill, and it will almost certainly be filibustered, say experts – a process in which opposing senators talk the bill to death. The filibuster can be avoided if the bill can secure 60 votes in favour, but amendments during the debate would probably still alter the legislation substantially.

The House Energy and Commerce committee will also introduce other climate legislation that will be subject to a similar vote. Assuming both bills pass, a conference committee must resolve the differences between them before it finally reaches the president's desk. The president, who is in office until January 2009, could then veto the legislation.

"What happened [this week] is an initial step in a very long and complicated process," said Anderson.