Possible mechanism of abrupt jump in winter surface air temperature in the late 1980s over the Northern Hemisphere
By Paul Homewood
I have often alluded to an apparent shift change in UK temperatures in the late 1980s, something which also seems to have happened in other parts of NW Europe.
It was with interest then that my attention was drawn to the above paper, which found the same phenomena in winter temperatures, not only in the UK, but also all over the Northern Hemisphere and attempted to explain it.
Here is the Abstract:
The authors point out that many other studies have found the same abrupt winter climate change, and have all offered various theories.
The study uses examples at Seoul, Tokyo and Beijing to highlight the size of this shift:
We can do the same analysis for the UK, where the shift seems to have occurred around 1988. The mean for 1988 to 2016 is almost a full degree higher than the 1955 to 1987 mean.
In the UK, at least, this step change is not confined to winter. Annual temperatures also exhibit a significant shift after 1988, this time of 0.8C.
The Kim paper argues that this shift was caused by changes in atmospheric pressure and circulation. I have no comment either way on this. But what does seem clear is that there is no obvious role for CO2 in any of this, as there is no explanation of how it could cause such abrupt changes.
While the paper’s conclusions make the obligatory reference to global warming, it finishes:
In this work, we did not address the issue regarding whether or not the change in regional dynamics can be associated with global warming. For that purpose, we need to carry out global warming experiments with climate models and/or analyze outputs CMIP5 models under different warming scenarios.