Reducing carbon emissions supposedly will reverse warming, which is allegedly occurring even though, according to statistics published by the World Meteorological Organization, there has not been a warmer year on record than 1998.
In other words, if each successive year isn't warmer than the last, global warming is only 'allegedly occurring.'
In support of his claim, Will links to this publication (PDF), which (in figure 2) ranks the last 150 years by temperature. He conveniently neglects to mention that, in the same publication, same figure in fact, you can see that the 14 warmest years since 1850 have all occurred since 1990.
Well, maybe Will thinks we've hit our peak, and we're on a downwards trend. Take a look at this graph, from NASA's Goddard Space Science Center and see if you can divine a downwards trend:
I've known brand new graduate students to get excited over fluctuations in noisy data like this, seeing a new trend from data point to data point, but they quickly get such misplaced enthusiasm beaten out of them. Whether it's temperature, the price of a barrel of oil, or gene expression data, fluctuations happen - which is why you don't take two data points and call it a trend.
Whatever the arguments over the causes of global warming, or the course of action to take, the scientific jury has rendered its verdict on this: the Earth is heating up, significantly. This is the second time in less than two months that Will has peddled his crank notion that global warming is a myth. Last time he basically implied that he could interpret the ice surface area data better than the researchers who generated it. This time, he apparently thinks that minor fluctuations are a bigger deal than the overall trend.
H/t to Jonathan Chait.