Yet another climate conference, yet more hot air, but so little time. Unless a serious deal is struck in Poznan this week, we are all in serious trouble.

Although the UN Climate Conference this week in Poznan is the smaller precursor meeting to the huge jamboree that will be Copenhagen next December, it is no longer acceptable to wait until the end of next year for the deal to be finalised. We have to act now. 

As the science editor of the Independent newspaper notes today: “Summing up what many scientists, environmentalists and politicians now think about the threat of climate change is simple: the world is drinking in the last chance saloon”.

You could argue that its last orders in the last chance saloon. On the one hand the head of Climate at the UN is argung that the world has to have specific targets by the end of next year at the Copenhagen meeting, but at the same time that he does not expect a “fully elaborated outcome” by the then.

The thought of failure in Copenhagen is just not acceptable. The world has to put in place now the building blocks for a successful meeting in Copenhagen. If they do not, the pace of climate change will have overtaken the chance of meaningful action for good. That means several things.

It means true leadership from the US and Barack Obama. The President-elect has to tell his representative at the talks, John Kerrry, to signal to the UN that the US is ready and willing to sign up to clear, specific cuts by next year. However, once again the messages are mixed. Although he will not be inaugurated for another month, Obama yesterday signalled his attention to tackle climate cahnge after a meeting with Al Gore. He said the days of denial and delay are over. Yet some analysts are saying that the global recession may mean Obama tries to delay the deal at Copenhagen.

This situation cannot be allowed to happen. The United States must pledge early next year what cuts they are prepared to adopt, giving enough time for developing countries like China and India to respond meaningfully by Copenhagen.

Any agreement has to take into consideration the fast changing nature of the science and evidence. There has to be a reappraisal of the science, so any targets reflect the new analysis. As Jonathon Porritt, the chair of the UK Sustainable Development Commission points out: “All the discussions in Poznan are based on the scientific consensus that emerged at the end of 2007 from the fourth assessment report of the Inter-Governmental Panel on Climate Change.”  The data used in that assessment is already three years old, and all the indications are that climate change is happening faster sooner and more vociferously.

Jim Hansen, the world’s pre-eminent climatologist, is now warning that the current target for stabilisation of CO2 at 450 parts per million in the atmosphere is totally inadequate. There is a growing school of thought that 350ppm represents a far more realistic safe upper limit (bear in mind that the concentration is already 384ppm.)

Other industrialised nations such as Japan, Canada and Australia also have to show true leadership. The word from Poznan is that they are trying to do the complete opposite.

Finally, the EU, which is negotiating its own climate and energy package, has to stop dithering and stick to a 30 per cent cut by 2020. If it sets a positive and ambitious target then the way forward to Copehagen becomes clearer for everyone and easier for Obama.

As one of the young activists who blocked London’s third runway earlier this week said – her generation had been let down by parent’s generation over climate. We will know just how badly if no comprehensive and radical deal is agreed in Poland.