When Kevin Rudd was handed the interim report of Ross Garnaut’s climate change review, he might have asked advisers about the typos.

“This says a 70% to 90% reduction by 2050. It should say 60%, right?”

Came the reply: “Um, no Mr Prime Minister, sir. If we’re going to save the planet, Professor Garnaut’s calculator says we’d better aim at 90% by 2050. You know, dire consequences and so on.”

Reducing carbon emissions by 60% by the middle of the century was already giving politicians reason to reach for their heart medication, but what’s the likely impact on both industry and the householder of adding another 30% to that target? If it’s even possible, how much pain will it cause?

“You can probably get up to a 30% saving to start with through greater efficiencies: using fluorescent tubes instead of incandescents, four cylinder cars instead of six, insulation of building, more public transport, manufacturing and industry getting its act together and so on,” University of Melbourne Professor of Economics John Freebairn told Crikey.

“But once you get beyond 50%, you’re really talking about producing electricity with nuclear or carbon sequestration, and at the moment politically, nuclear doesn’t seem to be on, and carbon sequestration is still a bit of a gamble. It’s very difficult for New South Wales and Queensland because they don’t have big reservoirs to put the carbon into.”

Freebairn says there is one unavoidable fact in this debate: the increased cost of carbon will be passed onto consumers. A $30 to $50 per tonne carbon tax, which Freebairn says is necessary to bring gas and possibly nuclear in over coal, will double electricity prices.

“That’s the real story. That’s what will make consumers think twice about running their air conditioners. With current oil prices, people are making the shift into smaller vehicles and onto public transport. There may well be a big decision about where you spend your holidays.”

Brad Shone, Energy Policy Advisor at the Alternative Energy Association, argues those decisions are already being made. “We’ve seen a shift toward smaller cars and part of that might be petrol prices, but part of it is a much greater awareness,” Shone told Crikey.

“We’ve seen a massive uptake of green power. The number of customers buying accredited green power products in September 2007 was 645,500, an increase of 8.5%, on the July figure. More impressively, this is a 46.7% increase on the figure from September 2006. Green power is exactly like any other power yet people are already willing to pay up to 25% more for their electricity just because it’s coming from a clean source.”

Indeed, the issue of time in the climate change debate is a vexed one. Lloyd Harrington of Energy Efficient Strategies says that fridge makers, for example, wouldn’t be able to improve the efficiency of their products by 70% by tomorrow. And if they, we’d all be taking out second mortgages to pay for them.

“But if we asked them to reduce energy consumption by 3% a year for the next 20 years, they’d be likely to comply because that’s what they’ve been doing over the last 20 years. That’s the orderly framework that’s required. If you want to have a 90% reduction over 50 years, that’s not too hard. But you can’t do nothing for 20 years and then decide to get on with it. It’s something you have to start on now.”

Someone ought to tell the new PM.