David Rose is notorious for fabricating quotes to misrepresent scientists. Now he’s doing the same thing to climate data. The UK Met Office recently reported that 2010 is “on track to become first or second warmest in the instrumental record”. Rose sprung into action, wrting a news story denying that global warming is happening. Rose claims:
Read carefully with other official data, they conceal a truth that for some, to paraphrase former US VicePresident Al Gore, is really inconvenient: for the past 15 years, global warming has stopped.
Who to believe, David Rose or your lying eyes?
(Graph above has anomaly for 2010 up to end of October in a lighter colour)
They go up a bit, then down a bit, but those small rises and falls amount to less than their measuring system’s acknowledged margin of error. They have no statistical significance and reveal no evidence of any trend at all.
Thus providing another example of why journalists need to learn statistics. You just have to look at the graph above to see that it has warmed since 1995. What Rose has misunderstood is what statistical significance means. Because the temperature has random ups and downs on top of the long term warming trend, you need about 16 years to conclude (with 95% confidence) that a trend in those 16 years is not a result of chance. So if the only temperature data we had was 1995-2009 (15 years!) we couldn’t conclude with 95% confidence that there was a trend. But we also couldn’t conclude (as Rose wants to do) that there is no trend — there simply isn’t enough data for a firm conclusion. But we have more data than just 1995-2009, so we can conclude (with greater than 95% confidence) that there is a warming trend.
In fact, since we have data for 2010 now, it is even now true that we have statistically signficant warming since 1995.
Rose then attempts a gotcha:
But though it was still successfully trying to influence media headlines during Cancun last week by saying that 2010 might yet end up as the warmest year, the small print reveals the Met Office climbdown. Last year it predicted that the 2010 average would be 14.58C. Last week, this had been reduced to 14.52C.
That may not sound like much.
Because it isn’t. Their prediction was only out by 0.06, which is really close. They even said when they made the prediction that their average error was 0.06. Compre that with David Rose’s [prediction that 2010 was the start of the mini ice age. Rose wasn’t brave enough to give a number, but presumably he was, at the very least, predicting that 2010 would be colder than 2008. The 2008 temperature was 14.31, so Rose was out by much much more than the Met Office.