The world stopped getting warmer almost 16 years ago, according to new data released last week.
The figures, which have triggered debate among climate scientists, reveal that from the beginning of 1997 until August 2012, there was no discernible rise in aggregate global temperatures.
This means that the ‘plateau’ or ‘pause’ in global warming has now lasted for about the same time as the previous period when temperatures rose, 1980 to 1996. Before that, temperatures had been stable or declining for about 40 years.
The new data, compiled from more than 3,000 measuring points on land and sea, was issued quietly on the internet, without any media fanfare, and, until today, it has not been reported.
This stands in sharp contrast to the release of the previous figures six months ago, which went only to the end of 2010 – a very warm year.
Ending the data then means it is possible to show a slight warming trend since 1997, but 2011 and the first eight months of 2012 were much cooler, and thus this trend is erased.
Some climate scientists, such as Professor Phil Jones, director of the Climatic Research Unit at the University of East Anglia, last week dismissed the significance of the plateau, saying that 15 or 16 years is too short a period from which to draw conclusions.
Others disagreed. Professor Judith Curry, who is the head of the climate science department at America’s prestigious Georgia Tech university, told The Mail on Sunday that it was clear that the computer models used to predict future warming were ‘deeply flawed’.
Even Prof Jones admitted that he and his colleagues did not understand the impact of ‘natural variability’ – factors such as long-term ocean temperature cycles and changes in the output of the sun. However, he said he was still convinced that the current decade would end up significantly warmer than the previous two.
The regular data collected on global temperature is called Hadcrut 4, as it is jointly issued by the Met Office’s Hadley Centre and Prof Jones’s Climatic Research Unit.
Since 1880, when worldwide industrialisation began to gather pace and reliable statistics were first collected on a global scale, the world has warmed by 0.75 degrees Celsius.
Some scientists have claimed that this rate of warming is set to increase hugely without drastic cuts to carbon-dioxide emissions, predicting a catastrophic increase of up to a further five degrees Celsius by the end of the century.
The new figures were released as the Government made clear that it would ‘bend’ its own carbon-dioxide rules and build new power stations to try to combat the threat of blackouts.
At last week’s Conservative Party Conference, the new Energy Minister, John Hayes, promised that ‘the high-flown theories of bourgeois Left-wing academics will not override the interests of ordinary people who need fuel for heat, light and transport – energy policies, you might say, for the many, not the few’ – a pledge that has triggered fury from green activists, who fear reductions in the huge subsidies given to wind-turbine firms.
Here are three not-so trivial questions you probably won’t find in your next pub quiz. First, how much warmer has the world become since a) 1880 and b) the beginning of 1997? And what has this got to do with your ever-increasing energy bill?
You may find the answers to the first two surprising. Since 1880, when reliable temperature records began to be kept across most of the globe, the world has warmed by about 0.75 degrees Celsius.
From the start of 1997 until August 2012, however, figures released last week show the answer is zero: the trend, derived from the aggregate data collected from more than 3,000 worldwide measuring points, has been flat.
Not that there has been any coverage in the media, which usually reports climate issues assiduously, since the figures were quietly release online with no accompanying press release – unlike six months ago when they showed a slight warming trend.
The answer to the third question is perhaps the most familiar. Your bills are going up, at least in part, because of the array of ‘green’ subsidies being provided to the renewable energy industry, chiefly wind.
They will cost the average household about £100 this year. This is set to rise steadily higher – yet it is being imposed for only one reason: the widespread conviction, which is shared by politicians of all stripes and drilled into children at primary schools, that, without drastic action to reduce carbon-dioxide emissions, global warming is certain soon to accelerate, with truly catastrophic consequences by the end of the century – when temperatures could be up to five degrees higher.
Hence the significance of those first two answers. Global industrialisation over the past 130 years has made relatively little difference.
And with the country committed by Act of Parliament to reducing CO2 by 80 per cent by 2050, a project that will cost hundreds of billions, the news that the world has got no warmer for the past 16 years comes as something of a shock.
It poses a fundamental challenge to the assumptions underlying every aspect of energy and climate change policy.
This ‘plateau’ in rising temperatures does not mean that global warming won’t at some point resume.
But according to increasing numbers of serious climate scientists, it does suggest that the computer models that have for years been predicting imminent doom, such as those used by the Met Office and the UN Intergovernmental Panel on Climate Change, are flawed, and that the climate is far more complex than the models assert.
‘The new data confirms the existence of a pause in global warming,’ Professor Judith Curry, chair of the School of Earth and Atmospheric Science at America’s Georgia Tech university, told me yesterday.
‘Climate models are very complex, but they are imperfect and incomplete. Natural variability [the impact of factors such as long-term temperature cycles in the oceans and the output of the sun] has been shown over the past two decades to have a magnitude that dominates the greenhouse warming effect.
‘It is becoming increasingly apparent that our attribution of warming since 1980 and future projections of climate change needs to consider natural internal variability as a factor of fundamental importance.’
Professor Phil Jones, director of the Climate Research Unit at the University of East Anglia, who found himself at the centre of the ‘Climategate’ scandal over leaked emails three years ago, would not normally be expected to agree with her. Yet on two important points, he did.
The data does suggest a plateau, he admitted, and without a major El Nino event – the sudden, dramatic warming of the southern Pacific which takes place unpredictably and always has a huge effect on global weather – ‘it could go on for a while’.
Like Prof Curry, Prof Jones also admitted that the climate models were imperfect: ‘We don’t fully understand how to input things like changes in the oceans, and because we don’t fully understand it you could say that natural variability is now working to suppress the warming. We don’t know what natural variability is doing.’
Yet he insisted that 15 or 16 years is not a significant period: pauses of such length had always been expected, he said.
Yet in 2009, when the plateau was already becoming apparent and being discussed by scientists, he told a colleague in one of the Climategate emails: ‘Bottom line: the “no upward trend” has to continue for a total of 15 years before we get worried.’
But although that point has now been passed, he said that he hadn’t changed his mind about the models’ gloomy predictions: ‘I still think that the current decade which began in 2010 will be warmer by about 0.17 degrees than the previous one, which was warmer than the Nineties.’
Only if that did not happen would he seriously begin to wonder whether something more profound might be happening. In other words, though five years ago he seemed to be saying that 15 years without warming would make him ‘worried’, that period has now become 20 years.
Meanwhile, his Met Office colleagues were sticking to their guns. A spokesman said: ‘Choosing a starting or end point on short-term scales can be very misleading. Climate change can only be detected from multi-decadal timescales due to the inherent variability in the climate system.’
He said that for the plateau to last any more than 15 years was ‘unlikely’. Asked about a prediction that the Met Office made in 2009 – that three of the ensuing five years would set a new world temperature record – he made no comment. With no sign of a strong El Nino next year, the prospects of this happening are remote.
Why all this matters should be obvious. Every quarter, statistics on the economy’s output and models of future performance have a huge impact on our lives. They trigger a range of policy responses from the Bank of England and the Treasury, and myriad decisions by private businesses.
Yet it has steadily become apparent since the 2008 crash that both the statistics and the modelling are extremely unreliable. To plan the future around them makes about as much sense as choosing a wedding date three months’ hence on the basis of a long-term weather forecast.
Few people would be so foolish. But decisions of far deeper and more costly significance than those derived from output figures have been and are still being made on the basis of climate predictions, not of the next three months but of the coming century – and this despite the fact that Phil Jones and his colleagues now admit they do not understand the role of ‘natural variability’.
The most depressing feature of this debate is that anyone who questions the alarmist, doomsday scenario will automatically be labelled a climate change ‘denier’, and accused of jeopardising the future of humanity.
So let’s be clear. Yes: global warming is real, and some of it at least has been caused by the CO2 emitted by fossil fuels. But the evidence is beginning to suggest that it may be happening much slower than the catastrophists have claimed – a conclusion with enormous policy implications.
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