the climate’s been going up and down – but the real question which I think everyone’s trying to address is – is this influenced by manmade activity in recent years and James is actually correct – the climate has not changed – the temperature has not changed in the last seventeen years.
So, the James mentioned above is one James Delingpole and the less said about him the better.
So, is Owen Patterson correct? Has the temperature not changed in the last 17 years? The answer is No. This is so incredibly frustrating as this mistaken view should have been put to bed ages ago. Why is it wrong? Well, what they are referring to is the fact that if one uses linear regression to analyse temperature anomaly data one discovers that the 2σ error in the best-fit trend is large enough that one cannot rule out that temperatures haven’t dropped – or been flat – in the last 17/18/19 years (depending on which dataset you choose to use).
However, as I pointed out in yesterday’s post, even though it is possible that temperatures have not changed for the last 17/18/19 years, it isn’t probably. For the GISSTEMP data (from NASA) there is only a 2.9% chance that the trend since 1995 is negative – hence a 97.1% chance that it is positive (and I have not engineered these numbers to be the same as for the consensus on AGW in the literature). You can go on to show that there is an 85% chance that the trend exceeds 0.05oC per decade and a 56% chance that it exceeds 0.1oC per decade.
So, Owen Patterson’s statement is simply wrong. The data does not indicate that temperatures have been flat for 17 years. They indicate that temperatures could have been flat but that this is highly unlikely and it is much more likely that temperatures have been rising and rising at a rate close to 0.1oC per decade. If you want more details you can read another post of mine that addresses the claim that we’re in a pause or a decline – we’re not in case you were wondering.