Sydney - The Australian government laid out plans Tuesday for a carbon-emissions trading scheme that industry critics said would cost jobs and environmentalists said would not save the planet.

The cap-and-trade scheme, to begin in July next year, includes the energy and transport sectors but excludes agriculture. The targets a 5 to 15-per-cent reduction in emissions on 2000 levels by 2020.

Australia is among the world's biggest polluters on a per capita basis, with emissions per head at least five times that of China. It is the world's largest exporter of coal, on which it relies for over 80 per cent of its domestic power generation.

The Labor government of Prime Minister Kevin Rudd doesn't have the majority in the upper house of parliament, the Senate, to pass the legislation it has proposed. It needs the support of either the opposition Liberal Party or independents.

"The question that will confront some senators is 'do you throw away something because you'd rather have everything,'" Climate Change Minister Penny Wong said.

Inevitably, Wong will have to accept amendments to the bill that might see major revisions to the scheme.

Greens' Senator Christine Milne branded the target for reductions as much too low, and her party is pushing for 25 per cent.

"We know that the wrong number is five and that it has to be changed," Milne said.

The government said lifting the target above 5 per cent would be possible if other countries also set targets in that range.

Wong ruled out bowing to demands from industry groups to postpone the implementation until Australia was out of recession.

"We do understand that there are global forces buffeting our economy, but what we also know is that we have to plan for the medium- and long-term as well," Wong said. (dpa)