Michael McCarthy: What's so depressing is the inevitability of all this

You might think you've heard it all before, and in a sense you have. There are not huge disparities between the core predictions of how climate change will affect the UK, released by the Government yesterday, and the earlier set of forecasts produced seven years ago. The central estimates of temperature rise by the 2080s, for example, are in the same ballpark.

But there are three important differences. Firstly, the new figures make a much stronger attempt at qualifying one of the key aspects of any predictions, which is uncertainty. For all the forecasts, there are now not only central figures, representing the best guess at what will actually happen, but also upper and lower estimates, which represent extremes with a 10 per cent chance of occurring. This enables risk to be mathematically quantified and is an essential component of future planning to cope with what global warming may bring.

Secondly, for the first time there are regional predictions in quite enormous detail, which will now enable the councillors and officials of Loamshire County Council, and even of Loamchester City Council, to get a feel for exactly what is coming their way in terms of hot, wet and dry – in other words, heatwaves, flooding, water shortages and all the other impacts which climate change is going to bring, and which they have to take into account.

But perhaps the most striking (not to say depressing) aspect of these figures is their new emphasis on inevitability. The temperature rises which are forecast for the 2080s might be avoided if the world makes a titanic effort at cutting carbon emissions, beginning in Copenhagen in December, but, even if we do, the Government now admits that by the 2040s a rise of more than two degrees in average summer temperatures is going to happen anyway.

For years the whole of British and European Union climate policy has been based on halting any temperature rise at the two degrees line. Does this not mean that the official objective is now unattainable? Asked about this yesterday the Environment Secretary, Hilary Benn, said: "Let's be frank. It's going to be tough."

Well, what else can he say?