Although it has been emerging for seven years or more, one of the most extraordinary scandals of our time has never hit the headlines. Yet another little example of it lately caught my eye when, in the wake of those excited claims that 2014 was “the hottest year on record”, I saw the headline on a climate blog: “Massive tampering with temperatures in South America”. The evidence on Notalotofpeopleknowthat, uncovered by Paul Homewood, was indeed striking.
Puzzled by those “2014 hottest ever” claims, which were led by the most quoted of all the five official global temperature records – Nasa’s Goddard Institute for Space Studies (Giss) – Homewood examined a place in the world where Giss was showing temperatures to have risen faster than almost anywhere else: a large chunk of South America stretching from Brazil to Paraguay.
Noting that weather stations there were thin on the ground, he decided to focus on three rural stations covering a huge area of Paraguay. Giss showed it as having recorded, between 1950 and 2014, a particularly steep temperature rise of more than 1.5C: twice the accepted global increase for the whole of the 20th century.
But when Homewood was then able to check Giss’s figures against the original data from which they were derived, he found that they had been altered. Far from the new graph showing any rise, it showed temperatures in fact having declined over those 65 years by a full degree. When he did the same for the other two stations, he found the same. In each case, the original data showed not a rise but a decline.
Homewood had in fact uncovered yet another example of the thousands of pieces of evidence coming to light in recent years that show that something very odd has been going on with the temperature data relied on by the world’s scientists. And in particular by the UN’s Intergovernmental Panel on Climate Change (IPCC), which has driven the greatest and most costly scare in history: the belief that the world is in the grip of an unprecedented warming.
How have we come to be told that global temperatures have suddenly taken a great leap upwards to their highest level in 1,000 years? In fact, it has been no greater than their upward leaps between 1860 and 1880, and 1910 and 1940, as part of that gradual natural warming since the world emerged from its centuries-long “Little Ice Age” around 200 years ago.
This belief has rested entirely on five official data records. Three of these are based on measurements taken on the Earth’s surface, versions of which are then compiled by Giss, by the US National Oceanic and Atmospheric Administration (NOAA) and by the University of East Anglia’s Climatic Research Unit working with the Hadley Centre for Climate Prediction, part of the UK Met Office. The other two records are derived from measurements made by satellites, and then compiled by Remote Sensing Systems (RSS) in California and the University of Alabama, Huntsville (UAH).
The adjusted graph from the Goddard Institute for Space Studies
In recent years, these two very different ways of measuring global temperature have increasingly been showing quite different results. The surface-based record has shown a temperature trend rising up to 2014 as “the hottest years since records began”. RSS and UAH have, meanwhile, for 18 years been recording no rise in the trend, with 2014 ranking as low as only the sixth warmest since 1997.
One surprise is that the three surface records, all run by passionate believers in man-made warming, in fact derive most of their land surface data from a single source. This is the Global Historical Climate Network (GHCN), managed by the US National Climate Data Center under NOAA, which in turn comes under the US Department of Commerce.