Of course it’s a trick designed to make the trend look waaaaay large. But it’s also turnabout — fair play turnabout, that it … of the way deniers have played exactly that trick for years. And still do!
And they didn’t do it to illustrate a point. They did it to decieve.
For quite a while, they used the trick with surface temperature data. They’d start their graph with 1998 — an extra-hot year — in order to make what follows look not so hot. Problem is, recent years have been so hot, so much hotter than 1998, even diehard climate anti-vaxxers can’t get away with that anymore.
Except for one data set. The satellite lower-troposphere data from RSS still shows 1998 so exaggerated that if you start there, you might give the impression temperatures have levelled off. To hell with a rigorous statistical treatment to test that idea. Just give the impression. So, guess which data set the denialati show the most, almost exclusively, love to death? Hint: it’s the one they can cherry-pick just the right moment to give the wrong impression.
But I can’t let Kevin Drum have all the fun. Here’s another version:
Here’s hoping some fake “skeptic” shows up to tell us all how this graph is cherry-picked, how dishonest it is to start with an extra-low year to make the following look extra-hot, how my stated “trend rate” (calculated by least squares regression — fancy math no less!) is so uncertain it’s meaningless, how short time spans can all too easily give the wrong impression. If some of the climate anti-vaxxers show up, I’d love to discuss that with ’em.
In the meantime, feel free to use this graph.