News analysis Householders who 'do their bit' to reduce greenhouse emissions may be wasting their time, says one expert, who is concerned about Australia's proposed emissions trading scheme.

But, says Denniss, emissions could be reduced even further if the scheme took into account people's altruism when it comes to "doing their bit" for the environment.

Any energy savings made by households will be passed on to their energy supplier.

The end result, he says, is that ordinary people who take the initiative to reduce emissions themselves will simply subsidise big companies to pollute.

the emissions trading scheme should be changed to ensure voluntary households reductions benefit the environment rather than simply freeing up extra pollution permits.