Here is a graph that I produced to illustrate the problem of using short term periods to make conclusions about climate trends. More detail (including how I created the graph can be found in this post.
The technique that the deniers use is eloquently illustrated by the animation below. A good name for it is Going Down the Up Escalator.
The data used is from the Berkely Earth Surface Temperature group (BEST). It was fairly difficult to produce a declining value for the last decade from the data. See the link above for an explanation.
The conservative U.K. newspaper the Daily Mail in London published an article Monday blasting Muller’s research, claiming that his Berkeley Earth Surface Temperatures (BEST) project produces a graph that — rather than showing increased global warming — shows that warming has stalled over the last decade.
“That’s incorrect,” Muller said Monday morning. “I mean, what they have done is an old trick. It’s how to lie with statistics, right? And scientists can’t do that because 10 years from now, they’ll look back on my publications and say, ‘Was he right?’ But a journalist can lie with statistics. They can choose a little piece of the data and prove what they want, carefully cutting out the end. If I wanted to do this, I could demonstrate, for example, with the same data set that from 1980 to 1995 that it’s equally flat. You can find little realms where it’s equally flat. What that tells me is that 15 years is not enough to be able to tell whether it’s warming or not. And so when they take 13 years, and they say based on that they can reach a conclusion based on our data set, I think they’re playing that same game and the fact that we can find that back in 1980, the same effect, when we know it wasn’t warming simply shows that that method doesn’t work. But no scientist could do that because he’d be discredited for lying with statistics. Newspapers can do that because 10 years from now, nobody will remember that they showed that.”