Climate change e-mails have been quoted totally out of context

We non-media-savvy scientists at the University of East Anglia have learnt a hard lesson this week — the truth is not enough in the face of a media-savvy enemy.

Character assassination is a purely diversionary tactic, but in the hacked e-mails affair it has been spectacularly successful.

How many of us would emerge unscathed if all our private e-mails over 20 years were opened by someone determined to prove that we were up to no good? The hackers have picked choice phrases out of context — and context is all: without it, these statements look awful. In the one most quoted, the director of the Climate Research Unit (CRU), Phil Jones, talks about using a “trick” to “hide the decline”. At first reading, this easily translates as “deceiving [politicians, other scientists, everyone] into believing the world is warming when it is actually cooling”.

But it doesn’t mean that at all. Jones is talking about a line on a graph for the cover of a World Meteorological Organisation report, published in 2000, which shows the results of different attempts to reconstruct temperature over the past 1,000 years. The line represents one particular attempt, using tree-ring data for temperature. The method agrees with actual measurements before about 1960, but diverges from them after that — for reasons only partly understood, discussed in the literature.

The tree-ring measure declines, but the actual temperatures after 1960 go up. They draw the line to follow the tree-ring reconstruction up to 1960 and the measured temperature after that. The notes explain that the data are “reconstructions, along with historical and long instrumental records”. Not very clear perhaps, but not much of a “trick”.

In another e-mail, Jones calls a sceptical research paper “garbage”, and says of this and another, that he “can’t see them being included” in the International Panel on Climate Change report that was being prepared. Such strong reactions are commonplace in academic research. What matters is what actually gets published. Were the papers excluded? No. Both are discussed appropriately in the report. If this was a conspiracy, it was singularly unsuccessful.

Climate sceptics would have us believe that the CRU data is invalid, and that the 20th-century warming is a construct entirely in the minds of a few scientists. This point of view surely has difficulty explaining why Arctic sea ice is declining and glaciers are retreating so rapidly, and why spring arrives earlier and autumn later than 50 years ago.

Andrew Watson, Royal Society Research Professor at the University of East Anglia.