Hottest ever June? Jury’s still out

It was scarcely surprising that the BBC, led by its arch-global warming zealot Roger Harrabin, should have used last week’s miniheat wave to trumpet that “last month was the hottest June ever recorded worldwide, and the fourteenth straight month that global heat records were broken”. This claim came from the US National Oceanic and Atmospheric Administration (NOAA), one of the world’s chief interlinked sources of data on global surface temperatures.

But what might also have been pointed out was that in recent years claims like this have, for two reasons, become increasingly controversial. For a start, as I have reported many times before, those responsible for compiling these records of global surface temperatures, including NOAA, have come under expert questioning for the way they have long been engaging in wholesale “adjustment” of their data, almost invariably in the same direction.

For earlier years, back to the 1930s and 1940s, their temperature figures have been revised downwards, while those for recent years have regularly been “adjusted” upwards – thus conveying that the world has been heating up much more than was justified by the original recorded data.

It was long universally accepted, for instance, that the hottest year since modern records began was 1998. This coincided with a record El Nino, the warm phase of the Pacific ocean current which raises temperatures all over the world. But since all this “adjusting” began, 1998 has slid down the list, so that it is now shown as having been exceeded by several subsequent El Nino years, culminating in a rise so dramatic that 1998 is now dwarfed by the figures coinciding with the latest El Nino, claiming 2016 to be Some like it hot: sunbathers enjoying the weather in Green Park, London, on July 19, the hottest day of the year so far in Britain the new ”hottest year in history”.

But what also gets tellingly ignored by the BBC and others is that, since 1998, there has been an increasingly glaring divergence between the global temperatures shown by these surface records and the much more comprehensive temperature measurements made by US satellites.

These clearly show 1998 as having been still easily the hottest year on record: more than 0.2 degrees C warmer than 2016. But the satellites have also lately been showing temperatures again dropping sharply, as happens each time an El Nino reverses into a La Nina.

This suggests that these dramatic fluctuations have nothing to do with human activity but arise naturally.

Several websites on both sides of the Atlantic have long been meticulously analysing all this; and in vain have asked the various bodies responsible for the surface records for a proper explanation as to why their figures need to be constantly “adjusted” in this way, and why they have thus come to differ so markedly from the findings of the satellites.

Unless these questions can be resolved, there is more than enough evidence to suggest that we should take any claim that 2016 is “the hottest year on record” with several hefty bags of salt.