From Mr Tony Welsh.

Sir, Robert Gentle (Letters, November 3) misleads when he says that climate science is a new field. John Tyndall is credited with having proved that the atmosphere produces a greenhouse effect in the 1850s. Even prior to that it was widely believed to be the case; ie, there was consensus. Climate change was first brought to the attention of a US president (LBJ) in 1965 and has been a mainstream concern since the 1970s. That is not to say that everything is perfectly understood, but most of the uncertainty concerns the detail effects of climate change on particular regions of the world rather than the macro effect on the average temperature of the earth's surface.