SIR – Dr Bruce Denness (Letters, January 28) claims that global temperatures have risen by 0.25C since 2011.
What he does not mention is that temperatures were depressed in 2011, because of La Niña at that time.
In fact, according to the HadCRUT4 dataset Dr Denness quotes, there has been no statistically measurable warming at all since 2005.
Meanwhile, global temperatures have been steadily falling in the last 12 months, as the effects of the record El Niño of 2015-16 gradually wear off. Paul Homewood
Sheffield, South Yorkshire
SIR – Dr Denness draws the wrong conclusions about the extremes of heat and cold currently experienced in different parts of the globe.
These lie within the historically measured temperature range and represent natural variability in the respective climate zones, telling us little about so-called global warming or the role of CO2. Since climate is a regional metric the concept of a global climate is meaningless.
I congratulate Dr Denness on the accuracy of the predictions of his model. However, I would be more convinced by his warning of uncontrolled warming from 2030 if his model had not just predicted the current temperature anomaly but also the cooling required to reach this figure. Dr Eric Huxter
SIR – I got a little lost when Dr Denness accused Christopher Booker (The Last Word, January 21) of cherry-picking his facts on global temperatures by selecting those in the northern hemisphere – but then went on to select temperatures in the southern hemisphere to support his side of the argument. Brian Christley