Scientists working at the forefront of knowledge are used to uncertainty. Future temperature predictions have upper and lower limits within which the eventual temperature is very likely to lie. However, even the lowest forecast temperature would be bad news for mankind.

All science carries with it some uncertainty and scientists in particular are very used to this. It is true that the uncertainty attributed to temperature predictions means that scientists admit that it is possible that there may be both higher and lower temperatures than the central prediction (although it is important to notice even the ‘lower bound’ (minimum) temperatures which the Intergovernmental Panel on Climate Change (IPCC) predict will increase with increasing greenhouse gas concentrations). For example, the IPCC estimates, on the basis of certain assumptions, that the best estimate of the increase in global surface temperature by the last ten years of the 21st century will be 1.8°C compared to the period 1980-1999, with a likely possibility (meaning two chances out of three) that the temperature increase will lie between 1.1 and 2.9°C. The general scientific and political consensus is that increases of 2oC or more would be ‘dangerous’.

The larger uncertainties surround what the weather will be in particular places in the future.