Boris Johnson has become a real embarrassment to London's scientific community after his latest outburst of climate change ‘scepticism’, which exposes not just a glaring weakness in his own knowledge but also within his team of advisers.

On Monday, Johnson used his Telegraph column to muse on the global climatic implications of a few days of wintry weather in the UK in January. He concluded that it might be time for policy-makers to consider whether the earth is heading for a "mini Ice Age".

This is complete rubbish, of course, and shows not only that Johnson does not understand the basic science behind global warming but also that he cannot distinguish between anecdote and evidence, or between weather and climate.

Claiming to be "an empiricist", Johnson suggested that this is "the fifth year in a row that we have had an unusual amount of snow" and that "I don’t remember winters like this". Unfortunately, his commitment to observational analysis apparently does not extend to consulting the Met Office’s records, which would have shown him that although the average temperatures in the UK during winters 2008-09, 2009-10 and 2010-11 were below average, last winter was actually warmer than average, as were most winters since 2000.

Furthermore, he would have discovered that the UK’s climate bears the unmistakeable footprint of global warming, with the seven warmest years on record all occurring since 2000. So why does the Mayor claim we are experiencing global cooling?

Well, it seems that the only person Johnson consults on this issue is his friend Piers Corbyn, who rejects the overwhelming evidence that rising atmospheric levels of greenhouse gases is driving the unambiguous rise in global average temperatures, and instead holds the sun directly responsible for trends in the Earth’s climate.

The trouble with Dr Corbyn’s theory, which he has not published in any peer-reviewed scientific journal, is that it is not supported by evidence. He does not even believe that the earth’s climate is controlled by the amount of energy radiated from the sun, but instead blames its magnetic activity, which increases and decreases cyclically about every 11 years and so clearly cannot be the main driver of global warming.

Johnson’s description of Dr Corbyn’s theory is an almost verbatim reproduction from one of his earlier columns last July (clearly the £250,000 he is allegedly paid each year is not high enough to guarantee original content for its readers), and is punctuated with references to JMW Turner, Shakespeare and the Aztecs, but largely devoid of scientific insight.

This latest gaffe follows his decision last year to invite Matt Ridley, a prominent climate change ‘sceptic’ and former chairman of Northern Rock, to speak at City Hall about how environmental risks are overblown, as part of the cultural celebration that accompanied the Olympics.

Perhaps we should not be surprised by all this given the complete lack of scientific education that Johnson has received. However, the Mayor has to take scientific evidence and expert knowledge into account when making many important decisions, not the least of which is how to adapt the capital’s transport system and infrastructure to withstand the impacts of global warming. He should not be relying on the fanciful theories of friends when it comes to issues that affect the lives and livelihoods of Londoners.

Johnson should make better use of the fact that the capital is home to many world class universities and scientific societies where he could consult genuine experts, most of whom now cringe every time he holds forth about climate change. But it is also time that the Mayor of London followed the example of central government departments by adding a professional and credible chief scientific adviser to his team.