AUDIO: Green MP Kennedy Graham speaks to Larry Williams about the new targets.

The government says it'll be five years before it's ready to tackle in earnest its ambitious new greenhouse emissions target announced today.

It's aiming for a 30% reduction on levels set in 2005.

Green Party climate spokesman Dr Kennedy Graham said the figure is patently inadequate - and comes with a touch of deception.

He said they've "switched the goalposts from 1990 which has always been the base year for the last 25 years, to 2005, to try and dress it up."

"30% off 2005 is actually 10-11% off 1990."

Climate Change Minister Tim Groser says 70% of our emissions come from the agricultural and transport - and transport will be the easier task.

He said that everywhere he looks "there are decreasing costs in electrics and hybrids and plug in hybrids, so maybe in 5 or 10 years we will be able to replace the gas in our tanks with renewable energy."

However, Mr Groser wasn't taking technological advances for granted.

"We're trying to peer into a distant future frankly, we have to be careful. We can't assume all of this technology is going to be commercially available for our people in the next 15 years, but I think you'd have to be pretty pessimistic to take that view."

Dr Kennedy Graham said this was nothing but spin.

"It's nowhere near enough to save the climate from a higher than 2 degree temperature increase."