Image by Froge

'Young people are being fed so many excuses about climate change, they don't bother to take action,' said Michele Condotti, head of WWF in Italy. And the biggest of these excuses is still the hoary old Uncertainty Excuse, the one that goes:  'We don't really know all the details. So let's wait till we are sure before we take action.'

'Look before you leap' is often a prudent attitude to take. But there are some circumstances where waiting doesn't reduce risk: it increases it.

Imagine you are standing near an Italian autostrada (highway) with hundreds of cars and trucks roaring up and down it. To your horror you notice a small child about to run across the autostrada.  Will you stop to say: 'Well, she will probably be hit, but I can't be absolutely certain so it would be more prudent to not take any action.'  Of course not!

Or would you say: 'I can't predict whether she will be hit by a green car or a red car, so I'd better wait to be sure.' Or: 'I am not sure she will be hit by a car at all - maybe she will be hit by a truck instead. Hmmm, there are really a lot of uncertainties here...I'd better wait till I know for sure.'

Obviously this kind of prudence would be absurd. No-one in their right mind would be stopped by uncertainties like this: they would simply grab the child and pull her out of harm's way. Because the relevant issue here is not working out which of these future options - exactly - is likely to come about and hurt the child: the relevant issue is that all the options are catastrophic!

And that's the same with climate change. We may not be certain about the details of what exactly will happen in the future. But we can be sure that all the options will be appalling if we don't take serious action fast - and that should be enough to wake us up.

It's a pity so many politicians  still pretend that it is not so. A few months ago, a UK politician casually dismissed the urgency of dealing with climate change - he didn't want us worrying about 'floating polar bears in 150 years' time'. 

He was wrong - on every count. 

First, the polar bears. I am very sorry to say that the best authorities say that these bears are finished. It's all over. There is nothing we can do any more to save these beautiful creatures, because we have already set in motion the climatic conditions that will guarantee their extinction.  Even if we stopped adding to global warming right now, the climate will stay too hot for polar bears to survive long-term.

It's like when we heat up a kettle of water. Even if we turned the gas off, the water in the kettle wouldn't instantly go cold: it will stay hot for many minutes. Similarly if we turned the greenhouse gas emissions off, the climate will stay too warm for many years - and we are not turning the gas off.   So the polar bears will die - and it will be because of us.  As will many thousands of other, less photogenic forms of animal and vegetable life.

Second, it's not only polar bears but thousands of other non-human life forms that we need to worry about - as well as people in their millions, or in their hundreds of millions, whose lives will be devastated by dying herds and failing crops; by floods, droughts and hurricanes of unprecedented severity; by new patterns of disease. 

Third, we have got to stop imagining that these serious effects will only happen in 150 years' time.  The consequences of climate change are ruining people's lives right now. In vulnerable communities in the global south, hundreds of thousands of people are already becoming jobless or homeless, getting sick, going hungry to starvation point, or even dying, as a direct result of climate change. And every year these dangers are hitting people harder. By 2015, only a few years away from now, Oxfam expects a third of a billion people to be suffering like this. We don't have to wait 150 years to see the results: they are visible now, if you don't put your hands over your eyes.

Finally, let's consider the proposition he poses: 'Why worry?' Why worry about making polar bears extinct? Why worry about the lives of hundreds of millions of children, and their mothers and fathers, being blighted by climate change? Well, millions of young people in Italy and anywhere else in the world would worry and take action - if they weren't misled by narcissistic politicians in Italy and in the UK.

It's time for politicians to tell us the truth - and to tell themselves the truth! At the UN's Climate Conference in Copenhagen this December, the world's leaders and their climate negotiators will be meeting to decided the fate of millions of us.  A OneClimate team will be following the negotiations day by day, producing a live video stream telling you the real story of climate change and what's being done to stop it.

Check into Copenhagen Live 24/7 on OneClimate.net - from 7 December all the way to the last day, 19 December. Don't be deluded.  Find out what's really going on. Bin the excuses. Worry. And do something.  Stop that child running across the road and being run over: the climate change juggernauts are on the move, and they kill.