SIR – Keith Sivyer, (T&A, December 15) shouldn’t let a couple of cold spells in recent winters obscure the fact that the world is still warming at an unprecedented rate. The 12 months up to the end of November were the hottest year worldwide in recorded history, November was the warmest for thousands of years globally, and at the moment it’s heating up nicely for the cricketers in Australia.

Earlier this year, 17 countries set their highest-ever temperature figures, and Moscow and Pakistan won’t forget the extreme heat, fires and flooding for years to come. In fact, Europe’s current cold weather is probably best explained by exceptional changes in the atmospheric circulation caused by this extra energy – and all of this is happening with the sun at an all time historical low and no sign of the warming El Nino surface water in the Pacific.

Keith Thomson, Heights Lane, Bradford