Mann is the scientist behind the famous “hockey stick” graph that first appeared in the journal Nature in 1998.
Mann and two other scientists Professor Raymond Bradley and Professor Malcolm Hughes had reconstructed temperatures in the Northern Hemisphere from the year 1400 to present day using data mainly from tree rings, ice cores and modern temperature readings.
The following year, the same three scientists extended their study to reconstruct 1000 years of temperatures and published this in the journal Geophysical Research Letters.
Each time the team plotted their data on graphs and each time the plots showed what is the now famous “hockey stick” shape with a sharp uptick in temperatures towards the end of the century.
What really got the ire of the climate science denial industry and its cheerleaders was that this second study showed that modern day temperatures were likely hotter than they had been in the so-called Mediaeval Warm Period.
This negated a key argument from sceptics – which they continue with today – that it’s been warmer in the recent past before the industrial revolution caused the westernised world to fall in love with fossil fuels.
Incidentally, it was never a very convincing argument anyway. Even if it was warmer in the past, it doesn’t challenge the multiple lines of evidence which point to burning fossil fuels and deforestation as the main cause of the rapid warming, ocean acidification and sea level rises we see now.
But anyway, enough of the climate science history lesson. Back to Michael Mann.