The strange 60s step change between global temps and the AMO …

Something that’s been on my mind for a while is that strange relationship – or, to be more precise, that conspicuous correlative relationship – between the evolution of North Atlantic (70N-0, 80W-0) SST anomalies (the AMO, only with trend included) and the global temperature anomalies:

Figure 1. Annual AMO (with trend imposed) vs. global temps (HadCRUt4, adjusted down 0.064 degrees post 1998) from 1860 to 2014.

Watch how the two curves above follow each other pretty neatly in the general ups and downs, and especially through the main cycle swings, all the way from the start until about 1960 and then again from about 1970 till today, only with the global then all of a sudden shifted up significantly above the AMO.

Doesn’t that shift look a bit peculiar? Here’s how it looks with the global curve moved down to fit:

Figure 2.

How large is this upward shift? In global terms it’s actually about one quarter of a degree (0.25C):

Figure 3.

There is clearly a major step change going on in that normally tight relationship between the North Atlantic and global temp anomalies some time between 1960 and 1970.

Why would there be such a step change? Could there be any natural explanations? Have we ever heard stories about this huge warming occurring in the 60s outside the North Atlantic region, apparently during this time utterly countering the AMO signal and hence pulling the global mean, on a permanent basis, one quarter of a degree up relative to the North Atlantic? It quite evidently never happened during the last 150+ years except somewhen in the 1960s. So what happened must have been quite … yes, exceptional.

But what happened? Why has such a major anomalous occurrence never been investigated? Studied? Described?

I’ll zoom in a bit to show you when this extraordinary global event must have taken place:

Figure 4.

A pretty impressive match, I would say, between the two time series from 1925 to 1963 and then again from 1969 to 1995. Obviously not so between 1963 and 1969 (the central gap in the global; note how I’ve shifted the global (green) curve down by 0.25 degrees post 1969 in order for it to stay aligned with the trended AMO curve).

I submit that the North Atlantic region, the wide stretch of ocean plus the continents on either side of it (prominently, Europe and North America), has been by far the most thoroughly and comprehensively monitored part of the world for the last 100-150 years. The general temperature evolution of this region during this time should thus be fairly well understood, particularly compared to that of the rest of the world.

Also, the close match between the multi-method measurements of North Atlantic SSTa and the global lower troposphere satellite temperature readings since the 70s works as compelling evidence of the reality and consistency of the conspicuous covariation observed between North Atlantic SSTa and global temps, that it is not just a biased artifact of an historical paucity of data points in the rest of the world.

I am not going to waste time and effort here to try and explain the 60s step change between North Atlantic SSTa and global temp anomalies under the pretense of appealing to various potential natural processes. Because there wouldn’t be any. This is quite obviously not a natural step change.

It is rather direct evidence of the global dataset having been severely tampered with to push an agenda, to try to fit the officially promoted global temperature evolution as closely as possible to the political AGW (‘CO2 radiative forcing’) story.

The clear global cooling period between 1940 and 1975 is nearly erased by more or less lifting the post-50s section of the time series up en bloc by one quarter degree (Figure 1), way after the fact (it was done progressively up through the 80s, 90s and the 00s), GISS as usual being the worst of the lot:

Figure 5.

Coincidentally, the so-called ‘divergence problem’ of Mike Mann and company (of ‘Hockey Stick’ fame), where the tree rings pointed towards continued cooling, but where global temps supposedly did not, occurred just after about 1960. Go figure.

Is the ‘divergence problem’ one that pertains to tree rings as a reliable temperature proxy? Or does it pertain to the reliability of the global temperature record post 1960?

Think about it.

I am not the first one to point out this somewhat disturbing discrepancy. Frank Lansner of the ‘Hide the decline’ blog did already back in 2010. His post on this topic is well worth a read.

Finally, after having removed the trended AMO curve from Figure 3, we end up with the global curve the way it probably should look, running from 1860 down to 2014:

Figure 6.

Today’s mean global temperature level seems to be, at most, 0.2 degrees higher than during the previous peak of the 1930s and 40s, not 0.5 as the ‘climate establishment’ want us to believe. The rise since the 70s, though, is still (nearly*) the same, about 0.5 degrees. But by now we all know how that came about, don’t we …?

* Barring the global down-adjustment of 0.064 degrees post 1998 (I’ll have another post up on that in not too long).

The rise in mean global temperatures since around 1880 (the second-to-last peak), nearly 135 years ago, appears to be approximately 0.45 degrees.

That’s a mean warming rate of a mere 0.33 degrees Celsius per century. And I still believe this to be a maximum figure.