ANALYSE - Two weeks ago the Daily Mail boasted that new data showed there was no significant global warming for the last 15 years. Many have debunked that claim. But close study of the graph used reveals some data manipulation as well.
Let’s start by stating that the Daily Mail article doesn’t show you the real long term trend in global warming. We showed earlier what that looked like with the same data. Each month we present an update of all 6 datasets combined to show the real long term trend. So we know what we are talking about.
But this is specifically about the graph the Daily Mail used.
First a minor point. They state that the graph covers the period 1997 till August this year:
The figures, which have triggered debate among climate scientists, reveal that from the beginning of 1997 until August 2012, there was no discernible rise in aggregate global temperatures.
Actually, their graph starts in September 1997. So let’s combine their graph with the real data from Hadcrut4. You can see the blue line starting before their red line:
So the red line is from the Daily Mail and the blue line is from the real data.
They’re missing the first two thirds of 1997. Exactly the period with much lower values. That’s no coincidence, that’s cherry picking for pros.
But that’s not all. If you look closely you see that their first data point is higher than the actual data and that their last 5 data points are lowered!
September 1997 has an actual value of 0.475. But in their graph it is displayed at 0.5. And at the end of the graph the last point should be 0.526, but it is put at 0.5 as well. The four data points before the last one are also slightly lower. See the two charts below for more detail.
Conclusion: they are not only cherry picking the data, they are also falsifying the graph in order to make it fit their statement. To me there is no excuse for lying by misrepresentation at all.
I do not expect the Daily Mail to publish an apology, but I do hope that all media that copied their “news” will publish a correction.
Attention Dutch readers: this post is an English version of the article that appeared earlier today in Dutch.
Update (23-10 21:30h): I’ve made a more clean version of the comparison. So you can see the differences at the beginning and the end better.