And so it came to pass that John Howard turned out to be the high water mark — pun intended — of the Coalition’s willingness to address global warming.

Some commenters thought I was overstating the case declaring that the Coalition was sliding into greenhouse denialism a couple of weeks ago. But bit by bit, day by day since then, they’ve retreated. First it was petrol, then it trade-exposed industries, then it was delaying emissions trading until the Howard Government’s preferred date of 2012. Now Brendan Nelson’s latest position, that Australia won’t act before India and China, means Australia won’t act at all, or at least not for a decade.

Instead, we’ll sit here and bake and whinge about petrol prices and “doing it tough”. Still, at least we can blame it all on foreigners, as we happily flog our coal to them.

Nelson calls an emission trading scheme “suicide”. Maybe he should talk to people living in low-lying Pacific island states, who really face the possibility of national extinction. Or talk to Bangladeshis, nearly half of whom live within 30 feet of sea level.

Still, not much Australia can do, right? We’re such tiny emitters in the scheme of things.

Since the one thing we all agree on is that India and China need to participate in efforts to reduce carbon emissions, and preferably via an emissions trading scheme that will enable international trading of carbon permits to ensure our exporters are not disadvantaged, what should Australia do? Sit back and declare “we’re doing nothing until you do something”? Or develop a world’s best practice trading scheme that shows they can work without causing massive economic dislocation and in fact benefit emerging technologies?

Which, one wonders, would maximise the chances of large developing country emitters agreeing to do something?

And then there’s the fact that, as the Prime Minister points out in The Australian today, our largest two-way trading partner, Europe, is already trading emissions. At least Kevin Rudd is now consistently saying emissions trading will impose costs on the community, which has been reluctant to do that until recently. But both he and his ministers appear to be content to let the rentseekers set the agenda in the debate for the moment.

If the Prime Minister wants to remain above it all, at least Penny Wong, Peter Garrett and Wayne Swan should be getting stuck into those sectors who want to neuter the trading scheme. At the moment it’s Ross Garnaut versus the rest, although the prof is handling himself reasonably well. What a shame Michael Costa, invited to debate Garnaut, dogged it.

Garnaut’s draft report doesn’t say much beyond what a bunch of Treasury officials could have come up with. But it comes with at least notional independence, and being external to Government has automatically garnered a lot more attention and credibility than an internal Government document. It has also shifted the debate onto the operation of the trading scheme.

Accordingly, Nelson’s stance has enormous risks. By essentially declaring opposition to an emissions trading scheme per se, the Coalition is dealing itself out of the debate. There also seems to be a growing sense that people — regardless of how seriously they take climate change – are sick of politicians talking about it and want them to do something. Nelson’s crass populism might have saved his own leadership for five minutes, but might also rebound on the Coalition.

The debate over emissions trading is at a tipping point, and next week’s Green Paper will be decisive. Some smart compensation and transitional options, coupled with effective prosecution of the case for moving quickly to a scheme, could set the debate up favourably for the government, and leave Brendan Nelson looking out-of-date. But poor presentation and options that can be portrayed negatively will provide more ammunition for the Coalition’s scare campaign.