It is make-up-your-mind time. The Intergovernmental Panel on Climate Change, set up by the United Nations in 1988, is about to publish its fifth assessment report. It will reaffirm that climate change is happening, is man-made and that the balance of evidence is that it is accelerating dangerously.
It is the work of 259 scientists from 39 countries who have to submit their work to detailed and open scrutiny from one another before the panel will publish. It is global science's best assessment — hedged with probabilities and acknowledging uncertainties — of where we are. We should be desperately concerned.
However, it will be met by a barrage of criticism from the new "skeptical" environmental movement — almost entirely on the political right — which, while conceding that global temperatures are rising, insists that there is still insufficient scientific proof to make alarmist predictions. There is certainly no need for governments to tax and regulate the burning of fossil fuels, or subsidize renewables, or come to "freedom-denying" international agreements.