Is the world still getting warmer? If so, how fast? Has there been a global warming ‘pause’ or ‘hiatus’ or not? Or has the recent warming rate been as fast, or even faster, than that measured in the 1990s?
Oddly enough, in a field where one is told that the science is ‘settled,’ there has been disagreement from several eminent scientists. Dr Ed Hawkins, a principal research fellow at Reading University, who no one could ever call a sceptic, wrote in his blog that even if one accepts NOAA’s data revisions, ‘there has clearly been a slowdown in the rate of warming when compared to other periods’.
Another one not buying the Karl paper’s message was Prof. Judith Curry of Georgia Tech. ‘Uncertainties in global surface temperature anomalies are substantially understated,’ she wrote. ‘This short paper is not adequate to explain the very large changes that have been made to the NOAA data set… while I’m sure this latest analysis from NOAA will be regarded as politically useful for the Obama administration [which is currently bent on using executive action to set unilateral emissions limits against the will of Congress], I don’t regard it as a particularly useful contribution to our scientific understanding of what is going on.’
I can reveal that the US House of Representatives science committee, led by the Texas Republican Lamar Smith, also has doubts. At the end of last month, committee staff sent emails to several experts in Britain, saying Mr Smith ‘is making climate change data within NOAA a priority’. The committee, they added, was seeking outside help to ‘analyse’ NOAA’s claims ‚Äì apparently, it would seem, because some members do not trust NOAA’s ‘input’ alone.
A committee aide told me: ‘NOAA released a conclusion it claims is based on scientific analysis. It has provided the Committee with documents to show their methodology and we’re seeking to confirm that their conclusions are accurate.’
Among those submitting evidence that challenges NOAA’s assertion is the UK sceptic think-tank, which is chaired by Lord Lawson, the Global Warming Policy Foundation. In a study published today by the GWPF, Dr David Whitehouse has analysed the raw temperature measurements behind the NOAA paper’s claim.
His key finding is that the difference between the old and revised data is ‘much smaller’ than the margin of error which NOAA admits affects all its temperature readings.
Moreover, Dr Whitehouse says, NOAA exaggerated its supposed recent warming trend by cherry-picking its start and end dates, choosing 2000, an unusually cold year, as its starting point, and 2014, a very warm one, as its end. Therefore, he writes, there is ‘no robust evidence that the hiatus does not exist’.
The graph shown here, produced by Dr Whitehouse, shows how wide those error margins are. Each data point is a revised NOAA world average annual temperature ‚Äì with the error bars added. (The temperatures shown are measured in thousandths of a degree above 14C.)
The same GWPF pamphlet contains an analysis by Gordon Hughes, Professor of Economics at Edinburgh. He finds that climate scientists have for years been ignoring statistical techniques designed to weed out random ‘noise’. These techniques have long been accepted as standard tools by researchers in fields such as econometrics and epidemiology, and Karl et al’s failure to deploy them means ‘the paper does not provide well-founded statistical evidence to draw any reliable conclusions about the rate at which global temperatures have been increasing’.
However, the most striking challenge to the paper comes from unexpected source ‚Äì the July issue of the same journal that published Karl, Science. A new paper by Dr Veronica Nieves of the California Institute of Technology finds includes that the pause is real after all. Crucially, Nieves used NOAA’s own data ‚Äì but drew very different conclusions. Needless to say, this paper has received no mainstream media publicity at all. The article you are reading now is its first mention outside the specialist literature and a handful of climate blogs. But in Prof Curry’s view, it shows ‘the hiatus lives’.
This is the run up to yet another giant UN climate conference due to take place in Paris at the end of the year. There, the long search for a binding emissions deal to limit the world’s temperature rise to the supposedly dangerous level of 2C above pre-industrial times is supposed finally to end. So it isn’t surprising that the public ‘debate’, if one can call it that, is even more febrile than usual. The Pope, of course, is doing his bit for atavistic green alarmism, aided by a panoply of distinguished leftists, such as Naomi Klein.
Moreover, we are now entering the second year of an ‘el Nino’ phenomenon in the Pacific, in which unusually warm sea surface temperatures there can be expected to increase the global average. Stand by for yet more headlines about records being smashed. Strong el Ninos are usually followed by equally strong ‘la Ninas’, when the Pacific turns cold, dragging down temperatures worldwide. My hunch is that if this happens in a year or two, it will attract much less attention.
Meanwhile, beneath the zealotry and bogus ‘certainty’, there are still huge areas of doubt ‚Äì both within climate science, and over climate policy: will any of the vastly expensive measures so fervently desired from the Paris UN conference actually work?
Very many people seem to find such issues too awkward to contemplate. Better to trumpet the message of Karl et al: the sceptics were wrong, and those who take them seriously are endangering their descendants’ future.