Five to 15. The numbers sound so casual, so innocuous; like an age range for a clothing brand, or the height in centimetres of a tomato plant, or the amount of time before dinner is ready.

But the sad — and yes, inconvenient — truth is that we have less than this amount of time in years to solve climate change now. We now have between four and 10 years before climate tipping points may set in, leading to out-of-control climate change where we’ve lost the opportunity we have now to at least get the damn thing under control.

The Government’s carbon pollution reduction target of five to 15% by 2020, revealed today by a source reported in the SMH , derails the global climate change negotiations and condemns our generation to a future much worse than the ones our current politicians inherited when they took office.

Five to 15% throws a spanner in the works of our last hope to solve climate change through a global treaty. A senior Chinese climate advisor in Poznan yesterday joined the increasingly concerned chorus of warnings from other nations to Australia: any target range that doesn’t include at least 25% will lock in failure at the crucial climate negotiations next year in Copenhagen.

Five to 15% makes a mockery of the platform that the Labor party went to the polls with before last year’s climate election. And all the people who voted for a party promising genuine climate solutions have every right to feel betrayed.

Many people — even some environment groups — will say today that now the target is set we can’t change it; that it’s impossible; we have to move on to the next battle. Certainly, the government’s argument is that it is not politically possible to do more than 15% because of the pressure they are under from the Coalition and from Australia’s biggest polluting companies.

The motto of the Australian Youth Climate Coalition’s Your Targets = Our Future campaign for the past five weeks has been: “We must demand the impossible to avoid the unimaginable”.

These targets are not acceptable. The Government must go back to the drawing board. Or in this case, back to the cabinet room. And stay there until cabinet decides on a target range that at least includes the minimum number that leaves the possibility of a global deal based on 450 parts per million on the table. Which is, of course, as Garnuat found: 25%.

Obama’s new website, the cleverly named change.gov, features a quote in the top right-hand corner: “Today we begin in earnest the work of making sure that the world we leave our children is just a little bit better than the one we inherit today”.

If this is the flagship quote of the Obama administration, it gives me some hope as I think about those scary numbers: five to 15%. That simple goal Obama has set — leaving the world better off for our kids — should be the clearest motivator for all of our politicians, no matter what party, what age, or links to polluting companies.

Imagine your reaction to the rejection of this simple idea if you were actually aged five to fifteen.

But Kevin Rudd’s capitulation to five to 15% just made it a lot harder for the Obama administration and every other Government which hasn’t yet set 2020 targets, by being one of the first countries to set the benchmark so incredibly low.

Five to 15% is a small and short-sighted target range; one that refuses to recognise the short window of opportunity we have right now to make deep carbon pollution cuts that will solve climate change and also create new jobs, new industries and new export markets through a “green new deal” that strong targets could create.

When I work up this morning I remembered a quote from Arthur C. Clarke: “This is the first age that’s ever paid much attention to the future, which is a little ironic since we may not have one.”