If you've had the unfortunate experience of having to watch Al Gore's "An Inconvenient Truth," then you've seen the graph known as the hockey stick.
It's called the hockey stick because it looks like a hockey stick laid on its side with the blade pointing up. It's also a crock. First, you'll notice if you look at the graph you'll notice there is no Medieval Warm Period. Also known as the Medieval Climate Optimum, it ran from about 800-1300 A.D. During this time, Greenland actually was green and they were growing grapes in England. In other words, it was warmer then than it is now. The graph also doesn't show the Little Ice Age which followed from about 1500 A.D. to about 1850 A.D.
Instead, you're given the impression that the temperature was always about the same until humans started driving SUVs.
A couple years back, Canadian statistician Steve McIntyre (proprietor of ClimateAudit.org) discovered that the math behind this graphic was biased in such a way so that you could put just about any numbers in and you'd get a hockey stick out.
Since then, the creators of the hockey stick -- and the activists at the Intergovernmental Panel on Climate Change -- have been trying to keep the discredited thing alive. Why? Not because it's good science -- it's not. Instead, they want to continue to be able to use the graphic.
For those of you who can't afford the time to look deep into the admittedly complex discussion that occurs over at ClimateAudit.org, Bishop Hill (neither a bishop nor really named Hill) has an excellent post laying out the shenanigans going on in an effort to keep the hockey stick -- science, truth and honesty be damned.