To follow-up on his previous article, where he claimed that stunning new data indicates El Nino drove record highs in global temperatures suggesting rise may not be down to man-made emissions, David Rose has a new article in which he claims that Now SECOND set of data shows world temperatures have cooled… and spikes were caused by El Nino – NOT by man. His previous article was very heavily criticised, both in the media, and by scientists. His new article is now claiming that he was right all along, and that his critics are green propagandists.

What I find quite remarkable is that David Rose is essentially presenting his own scientific analysis, despite numerous scientists pointing out that he is wrong, and despite having no actual expertise. However, David Rose is being a little cleverer in this new article, as he has slightly shifted what he’s claiming; he’s now talking about spikes, rather than records. Let’s remind ourselves of what he said in his first article

Some scientists, including Dr Gavin Schmidt, head of Nasa’s climate division, have claimed that the recent highs were mainly the result of long-term global warming. Others have argued that the records were caused by El Nino, a complex natural phenomenon that takes place every few years, and has nothing to do with greenhouse gas emissions by humans. The new fall in temperatures suggests they were right.

What’s being suggested by some scientists is that the recent record warm years were not caused by the El Niño; they would have been records even without the El Niño contribution. The reason being that the contribution from El Niño is typically around 0.2oC, or less, and hence even correcting for this leads to these still having been record years.

I thought I would try, here, to illustrate the basic point. The figure on the right shows the HadCRUT4 monthly data relative to the 1961-1990 mean (blue), a 12 month running average (red), and the linear trend from 1970 – October 2016. I’m ignoring the uncertainty in the trend (it would be about ± 0.03oC) as it isn’t really relevant for the basic point. This will also be a little simple, so if you want more detail, read Tamino’s posts.

The table below shows the mid-year trend values, and global annual averages for a recent years that have either been record years, or close to record years. Let’s start with 1998. The mid-year trend value was 0.336; the global annual average for that year (which was associated with a strong El Niño) was 0.537. This is consistent with the El Niño enhancing global temperatures by maybe two-tenths of a oC. Of course, there may be other factors that also influenced this, but it was unlikely to be much more than this. Now consider 2014. The mid-year trend value and the global annual average are quite similar; there is little El Niño effect, and yet it still beats 1998. What about 2015? The global annual average is almost two-tenths of a oC higher than 2014, and yet the El Niño had only just started. There was almost certainly some El Niño influence, but probably not as much as two-tenths of a oC (most estimates suggest a bit less than 0.1oC). Hence, 2015 would probably have beaten 2014, even without some help from the El Niño.

Year Mid-year trend value Annual global average 1998 0.336 0.537 2005 0.458 0.545 2010 0.545 0.558 2014 0.615 0.576 2015 0.632 0.761 2016 0.649 (0.817)

We don’t yet know about 2016 (it’s not yet over) but the average to October is 0.817. It may be that it will only be warmer than 2015 because of a larger El Niño contribution, but that doesn’t change that the recent records were not simply because of the El Niño. I’ve also seen analyses suggesting that 2016 would still beat 2015, even if corrected for El Niño.

I should, however, make some things clear. This is a very simple analysis. The linear trend is not a perfect representation of the forced response, and variations from that trend do not necessarily correctly represent the variability about the forced response (if anyone thinks I’ve blundered spectacularly here, feel free to let me know). However, what this does indicate is that this variability is typically (for annual averages, at least) at the level of two-tenths of a oC, or lower. Hence, this variability (mostly El Niño in the last year or so) cannot explain the recent record warm years, as suggested by David Rose.

A couple of others things for David Rose to ponder (if he bothers to read this, that is).

David Rose seems to suggest that he would prefer a politer debate about climate change. If so, maybe he should avoid using pejorative labels (like green propagandists ) to describe those who disagree with what he presents. He doesn’t have to, but if he does he should probably avoid complaining when he gets labelled in a way he doesn’t like.

) to describe those who disagree with what he presents. He doesn’t have to, but if he does he should probably avoid complaining when he gets labelled in a way he doesn’t like. David Rose seemed really put out about being regarded as a science denier. If this was genuine – rather than feigned – maybe he should avoid RTing, and associating with, those who very obviously are. Two examples would be Steven Goddard and James Delingpole.

Addendum:

One of the most amusing things about this whole saga was a Mail Online article about

‘Science doesn’t care about your opinion’: The Weather Channel launches scathing attack on Breitbart for ‘misleading’ article on climate change that failed to point out that the origin was really David Rose in the Mail Online.