We pay insurance on our car, homes and contents, so why not on our planet? Why aren't we preparing for the worst, for our grandchildren's sake?

The politics of climate change is enough to make your head explode. We seem to have come to a consensus in New Zealand that carbon should have a price, but we're still re-arranging who pays that price. The previous government had one plan, the new government and the Maori Party, however, have fiddled with that, asking the taxpayer to subsidise polluters in the early years. We've got an emissions trading scheme that will be the first in the world to cover "all-sectors", but we can't settle on when each sector will join the scheme. We've agreed to cut emissions by 10-20 percent by 2020, but is it enough? The science seems to demand closer to a 40 percent cut if we are to keep the average global temperature from increasing by more than two percent. Do we need a tax or is an ETS sufficient? Seriously, head-exploding stuff.

The political realist might say that amounts to sure and steady progress in  a country with a surprisingly high number of climate change deniers and a risk-wary government. But is it enough? The science seems to demand more. And what if, God forbid, that still isn't enough and we need more again.

I've been mulling over an idea about how we might do 'more' since I read Professor Sir Peter Gluckman's nifty summary of climate change that he published in August. This point in particular stuck with me:

There is a remote possibility that if we did little or nothing then the temperature would not rise to unacceptable levels. But we cannot gamble the future of the whole planet on the low probability of that occurring. We do many things in life that are based on the balance of probabilities, for example we think it prudent to insure our houses and wear seat belts in our cars not because we plan to have a fire or a crash, but rather because we are weighing the cost of the insurance premium or the minor inconvenience of putting on the seat belt against the significant risk of damage to our finances or ourselves if those events were to happen. It is the same with climate change – the collective wisdom of the scientific community is that action is needed to address global warming because without action the potential risk to the planet and ourselves is too high.

Likening the action needed to address climate change to taking out an insurance policy makes sense. At a time when most New Zealanders have given up on ever understanding the whole greenhouse shooting match and we risk confusion turning into apathy, it's the kind of thing most will understand. If you insure your car and house against an unlikely but potentially crippling event, doesn't it make sense to treat our planet – the only home we have – in the same way.

To me that suggests a policy alternative in the debate about what we can do about climate change; a debate that often focuses on carbon tax versus emissions trading or the structure of the ETS and our emissions reduction target. That is, earth insurance.

Why would we take out earth insurance? As it stands, we're relying on emissions trading, trees and hoped-for new technology to cut our greenhouse gases. But it's a cautious approach; as the government has repeatedly said, it won't risk harm to the economy when we don't know exactly how much the climate will change. Other nations are saying much the same thing. Around the world, nearly every country is committed to only moving as fast as the slowest mover, lest they sacrifice economic advantage.

But what if the worst happens; the equivalent of the house being burgled or the diamond ring disappearing down the drain? What if we need to act much more urgently that we think? What if we fail, and are faced in 50 years with what climate scientists call "dangerous climate change"? What if that undermines our economy and we are faced with a desperate world on our doorstep?

We're hoping for the best, not preparing for the worst. We're not taking out insurance.

Why not? Few households and even fewer businesses are that cavalier. It's an expense that both understand and accept as a sensible precautionary approach, it can be kept relatively cheap and it can be easily targeted.

I'm not sure of the best way of configuring it; you all might have some ideas on that. It would need to be mandatory; but KiwiSaver hardly caused a revolution, so I think that's possible.

We could make it an insurance paid by land-owners. I can't begin to think what level to set it at, but essentially the more land you own, the more you pay. That would tend to ask more of farmers and business owners, which seems fair. It would have the added benefit of providing a (small) disincentive to multiple home-owners.

Or it could be a surcharge on top of car registrations. The more cars you have, the more you pay for the risk you're taking with the environment. Or it could be aligned with the ETS sectors and be gathered from business alone.

How would it work? It would create a capital fund not unlike the Super Fund. Part of the money would be used to plant trees and buy carbon credits. That would help us in the meantime. The rest would be invested and saved just in case... in case we face climate migration, in case we need to bail out pacific atoll nations, in case our land-based industries take a hit, in case we fail so miserably in the next decade that our grandchildren and great-grandchildren need our help.

And that last point is the political message – we're doing this for our grandchildren. If the climate changes more than we hope and if later this century the country needs to rapidly adapt to a very different kind of world, don't we want our grandchildren to be prepared? Given that we know there's a chance of catastrophe, don't we want to take out some insurance for their sake?

How could we look them in the eye and say, well, we knew it could go really bad, but we did nothing?

Of course the flip side is that if we are successful in containing climate change or adaptation is less dramatic than we might fear, that insurance can be paid back. In introducing this insurance, the government could set conditions. If the money isn't needed by 2060, or 2090, or whenever, it could be shared amongst taxpayers, or paid back proportionately to those who paid it.

That's a better deal than your insurance company would offer, but it would make it more politically acceptable. Who doesn't want to look after their grandchildren?

In other words, if the worst happens, our descendants are covered. If it doesn't, they simply have a nice nest-egg. What a legacy to leave.

This, as you can tell, is a skeleton of an idea without any flesh on it. Any suggestions?