Carried out by McGill University’s Shaun Lovejoy, the study used ‘multi-proxy climate reconstructions’ developed by scientists in recent years to estimate historical temperatures. Lovejoy then applied fluctuation-analysis techniques from non-linear geophysics to examine the temperature variations over wide ranges of time scales.
The results indicated that the hypothesis that global warming since 1880 is due to natural variability can be ruled out ‘with confidence levels greater than 99 per cent, and most likely greater than 99.9 per cent’, Lovejoy said.
‘This study will be a blow to any remaining climate-change deniers,’ he continued. ‘Their two most convincing arguments – that the warming is natural in origin, and that the computer models are wrong – are either directly contradicted by this analysis, or simply do not apply to it.
‘We’ve had a huge fluctuation in average temperature since 1880 – on the order of about 0.9°C,’ he concluded. ‘This study shows that the odds of that being caused by natural fluctuations are less than one in a 100 and are likely to be less than one in a 1,000.’
This story was published in the June 2014 edition of Geographical Magazine