Has global warming stopped?

'The global temperature of 2007 is statistically the same as 2006 and every year since"

'The fact is that the global temperature of 2007 is statistically the same as 2006 and every year since 2001'. Plus read Mark Lynas's response

Global warming stopped? Surely not. What heresy is this? Haven’t we been told that the science of global warming is settled beyond doubt and that all that’s left to the so-called sceptics is the odd errant glacier that refuses to melt?

Aren’t we told that if we don’t act now rising temperatures will render most of the surface of the Earth uninhabitable within our lifetimes? But as we digest these apocalyptic comments, read the recent IPCC’s Synthesis report that says climate change could become irreversible. Witness the drama at Bali as news emerges that something is not quite right in the global warming camp.

With only few days remaining in 2007, the indications are the global temperature for this year is the same as that for 2006 – there has been no warming over the 12 months.

But is this just a blip in the ever upward trend you may ask? No.

The fact is that the global temperature of 2007 is statistically the same as 2006 as well as every year since 2001. Global warming has, temporarily or permanently, ceased. Temperatures across the world are not increasing as they should according to the fundamental theory behind global warming – the greenhouse effect. Something else is happening and it is vital that we find out what or else we may spend hundreds of billions of pounds needlessly.

In principle the greenhouse effect is simple. Gases like carbon dioxide present in the atmosphere absorb outgoing infrared radiation from the earth’s surface causing some heat to be retained.

Consequently an increase in the atmospheric concentration of greenhouse gases from human activities such as burning fossil fuels leads to an enhanced greenhouse effect. Thus the world warms, the climate changes and we are in trouble.

The evidence for this hypothesis is the well established physics of the greenhouse effect itself and the correlation of increasing global carbon dioxide concentration with rising global temperature. Carbon dioxide is clearly increasing in the Earth’s atmosphere. It’s a straight line upward. It is currently about 390 parts per million. Pre-industrial levels were about 285 ppm. Since 1960 when accurate annual measurements became more reliable it has increased steadily from about 315 ppm. If the greenhouse effect is working as we think then the Earth’s temperature will rise as the carbon dioxide levels increase.

But here it starts getting messy and, perhaps, a little inconvenient for some. Looking at the global temperatures as used by the US National Oceanic and Atmospheric Administration, the UK’s Met Office and the IPCC (and indeed Al Gore) it’s apparent that there has been a sharp rise since about 1980.

The period 1980-98 was one of rapid warming – a temperature increase of about 0.5 degrees C (CO2 rose from 340ppm to 370ppm). But since then the global temperature has been flat (whilst the CO2 has relentlessly risen from 370ppm to 380ppm). This means that the global temperature today is about 0.3 deg less than it would have been had the rapid increase continued.

For the past decade the world has not warmed. Global warming has stopped. It’s not a viewpoint or a sceptic’s inaccuracy. It’s an observational fact. Clearly the world of the past 30 years is warmer than the previous decades and there is abundant evidence (in the northern hemisphere at least) that the world is responding to those elevated temperatures. But the evidence shows that global warming as such has ceased.

The explanation for the standstill has been attributed to aerosols in the atmosphere produced as a by-product of greenhouse gas emission and volcanic activity. They would have the effect of reflecting some of the incidental sunlight into space thereby reducing the greenhouse effect. Such an explanation was proposed to account for the global cooling observed between 1940 and 1978.

But things cannot be that simple. The fact that the global temperature has remained unchanged for a decade requires that the quantity of reflecting aerosols dumped put in our atmosphere must be increasing year on year at precisely the exact rate needed to offset the accumulating carbon dioxide that wants to drive the temperature higher. This precise balance seems highly unlikely. Other explanations have been proposed such as the ocean cooling effect of the Interdecadal Pacific Oscillation or the Atlantic Multidecadal Oscillation.

But they are also difficult to adjust so that they exactly compensate for the increasing upward temperature drag of rising CO2. So we are led to the conclusion that either the hypothesis of carbon dioxide induced global warming holds but its effects are being modified in what seems to be an improbable though not impossible way, or, and this really is heresy according to some, the working hypothesis does not stand the test of data.

It was a pity that the delegates at Bali didn’t discuss this or that the recent IPCC Synthesis report did not look in more detail at this recent warming standstill. Had it not occurred, or if the flatlining of temperature had occurred just five years earlier we would have no talk of global warming and perhaps, as happened in the 1970’s, we would fear a new Ice Age! Scientists and politicians talk of future projected temperature increases. But if the world has stopped warming what use these projections then?

Some media commentators say that the science of global warming is now beyond doubt and those who advocate alternative approaches or indeed modifications to the carbon dioxide greenhouse warming effect had lost the scientific argument. Not so.

Certainly the working hypothesis of CO2 induced global warming is a good one that stands on good physical principles but let us not pretend our understanding extends too far or that the working hypothesis is a sufficient explanation for what is going on.

I have heard it said, by scientists, journalists and politicians, that the time for argument is over and that further scientific debate only causes delay in action. But the wish to know exactly what is going on is independent of politics and scientists must never bend their desire for knowledge to any political cause, however noble.

The science is fascinating, the ramifications profound, but we are fools if we think we have a sufficient understanding of such a complicated system as the Earth’s atmosphere’s interaction with sunlight to decide. We know far less than many think we do or would like you to think we do. We must explain why global warming has stopped.

David Whitehosue was BBC Science Correspondent 1988–1998, Science Editor BBC News Online 1998–2006 and the 2004 European Internet Journalist of the Year. He has a doctorate in astrophysics and is the author of The Sun: A Biography (John Wiley, 2005).] His website is

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Why don’t we learn from our mistakes – even when it matters most?

Juan Rivera served ten years of prison time until DNA evidence overturned his sentence. But even now, some maintain his guilt.

On the afternoon of 17 August 1992, an 11-year-old girl called Holly Staker walked from her home to a neighbour’s apartment in Waukegan, a small town in Illinois. She had been asked to babysit two children, a girl aged two and a boy of five. By 8pm Holly was dead. An unidentified intruder had broken into the apartment, violently raped her, and stabbed her 27 times. The local police force pursued 600 leads and interviewed 200 people, but within a few weeks the trail had run cold.

Then, through the testimony of a jailhouse informant, police happened upon a new suspect: Juan Rivera, a 19-year-old man who lived a few miles south of the murder scene. Over four days, Rivera, who had a history of psychological problems, was subjected to a gruelling examination by the Lake County Task Force. At one point it seemed to get too much for Rivera. Officers saw him pulling out a clump of hair and banging his head on the wall.

On the third day, as the interviewers’ tone became aggressive, Rivera finally nodded his head when asked if he had committed the crime. By this time, his hands and feet were tied together, and he was confined to a padded cell. On the basis of his confession, police prepared a statement for Rivera to sign.

There were no witnesses to the crime. There was no physical evidence. But there was a brutally murdered young girl, a community still in mourning, and that signed confession. The jury didn’t take long to make up their minds. Rivera was convicted of first-degree murder and sentenced to life in prison.

Many journalists who covered the case were uneasy. They could see that the case hinged on the confession of a disturbed young man, who had retracted hours after signing it. But the police and prosecutors felt vindicated. It had been a troubling crime. A man had been sentenced. Holly’s family could find closure.

Or could they?


Eight years earlier, in 1984, Alec Jeffreys, a British scientist, had the insight that would lead to DNA fingerprinting – a technique that would transform the criminal justice system. In the absence of contamination, and provided the test is administered correctly, the odds of two unrelated people having matching DNA is roughly one in a billion. In certain cases, such as rape, it would in time be possible to identify the attacker conclusively, based on DNA extracted from the crime scene. After all, if the police swabbed the sperm found in the victim, they could narrow the number of potential suspects to just one. This is why DNA fingerprinting has helped to secure thousands of convictions – it has a unique power in establishing guilt.

But it also has implications for cases that have already been tried: the power to exonerate. If the DNA from the sperm in a rape victim has been stored, and if it does not match that of the person serving time in prison, the conclusion is difficult to deny: it came from a different man, the real criminal.

In August 1989, just months after DNA fingerprinting technology became advanced enough for use in the criminal justice system, Gary Dotson, who had been convicted of a 1977 rape in Chicago, was released from jail, having consistently proclaimed his innocence. Underwear worn by the victim had been sent for DNA testing, which showed that the semen belonged to a different man. Dotson had served more than ten years in jail.

The first DNA exoneration in the UK involved Michael Shirley, a young sailor who had been convicted of the rape and murder of Linda Cook, a barmaid working in Portsmouth, in December 1986. A simple DNA test performed in 2001, after police finally admitted they had stored swabs from the crime, proved that the semen found in the victim did not belong to Shirley. He had served 16 years at the time of his release.

By 2005, in the United States alone, the convictions of more than 300 people had been overturned following DNA tests. It seemed that the criminal justice system was getting it wrong repeatedly. In situations where evidence had been kept, clients of the Innocence Project, an American charity that helps prisoners who say they were wrongfully convicted, were exonerated in almost half the cases. A study led by Samuel R Gross, a professor at the University of Michigan Law School, concluded: “If we reviewed prison sentences with the same level of care that we devote to death sentences, there would have been over 28,500 non-death-row exonerations [in the US] in the past 15 years rather than the 255 that have in fact occurred.”

At that point, Juan Rivera, the man convicted of killing Holly Staker, had been in jail for almost 13 years. His lawyers decided to apply for a DNA test. It hadn’t been performed at the trial because techniques were not, at that time, sufficiently advanced to analyse very small samples of tissue. When the results came back they were conclusive: the semen found inside Holly Staker did not belong to Rivera.

He was yet another victim of wrongful conviction.


When a system produces an error, it is a tragedy for the person on the wrong side of the mistake. But it is also a precious learning opportunity, a chance to figure out what went wrong, and make reforms to the system to ensure that the same mistakes don’t happen again.

Aviation is a powerful model in this respect. Every plane is equipped with two black boxes, which record vital information. If an accident occurs, these boxes are recovered, the failure analysed, and reforms implemented. Pilots report near-miss events, too, which are statistically analysed in order to help prevent accidents.

In 1912, eight of the 14 qualified US army pilots died in crashes. In 2014, the accident rate for major airlines had dropped to just one crash for every 8.3 million take-offs. That’s the power of learning from mistakes.

Broadly speaking, this is how science works. Scientists make testable predictions; when these fail, the theories are reformed. As the philosopher Karl Popper put it: “The history of science . . . is a history . . . of error. But science is one of the very few human activities – perhaps the only one – in which errors are systematically criticised and fairly often, in time, corrected. This is why . . . we can speak clearly and sensibly about making progress there.”

But there is a practical problem with adopting this model of progress. Many people don’t like to admit to their mistakes. They do not meet their failures with intellectual honesty and a willingness to understand what went wrong, but with back covering and defensiveness. This has a simple consequence: if mistakes are not learned from, they will be made again and again. And again.

In his famous studies of “cognitive dissonance” in the 1950s, the sociologist Leon Festinger discovered the array of tactics used by people to spin, reframe and cover up their mistakes. A classic example involved a small group of cult members. They had left their families to live with a housewife called “Marian Keech” (real name: Dorothy Martin), who had predicted the world would end before dawn on 21 December 1954. She had also prophesied that the members of the cult would be saved from the looming apocalypse by a spaceship that would land at Keech’s small house in suburban Minnesota at midnight.

Neither the apocalypse nor the spaceship materialised (Keech’s husband, who was a non-believer, had gone to his bedroom and slept through the whole thing). This was an unambiguous failure. Keech had said the world would end, and that a spaceship would save true believers. Neither had happened. The cult members could have responded by altering their beliefs about Keech’s supernatural insights.

Instead, they altered the “evidence”. At first, the cult members kept checking outside to see if the spaceship had landed. Then, as the clock ticked past midnight, they became sullen and bemused. Ultimately, however, they became defiant. Just as Festinger had predicted before he infiltrated the cult, the faith of hardcore members was unaffected by what should have been a crushing disappointment. In fact, their faith seemed to grow stronger.

How is this possible? As Festinger recounted in his book When Prophecy Fails, first published in 1956, they simply redefined the failure. “The godlike figure is so impressed with our faith that he has decided to give the planet a second chance,” they proclaimed (I am paraphrasing only a little). “We saved the world!” Far from abandoning the cult, members went out on a recruitment drive. As Festinger put it: “The little group, sitting all night long, had spread so much light that God had saved the world from destruction.” They were “jubilant”.

This may sound bizarre, but it is, in fact, commonplace. Festinger showed that this behaviour, though seemingly extreme, provides an insight into psychological mechanisms that are universal. When we are confronted with evidence that challenges our deeply held beliefs we are more likely to reframe the evidence than we are to alter our beliefs. We simply invent new reasons, new justifications, new explanations. Sometimes we ignore the evidence altogether.

Think, for example, of health care. In her book After Harm, published in 2005, the American researcher Nancy Berlinger investigated how doctors reframe their mistakes. “Observing more senior physicians, students learn that their mentors and supervisors believe in, practise and reward the concealment of errors,” she wrote. “They learn how to talk about unanticipated outcomes until a ‘mistake’ morphs into a ‘complication’. Above all, they learn not to tell the patient anything.”

This is partly about fear of litigation, but also about the protecting ego. Think of the language associated with senior physicians. Surgeons work in a “theatre”. This is the stage where they “perform”. How dare they fluff their lines? As the safety expert James Reason put it: “After a long education, you are expected to get it right. The consequence is that medical errors are marginalised and stigmatised.”

But if doctors do not learn from their mistakes, they are destined to repeat them. A report by the UK National Audit Office in 2005 estimated that up to 34,000 people are killed each year as a result of human error in the health-care system. It put the overall number of patient incidents (fatal and non-fatal) at 974,000. In the US, annually, 400,000 people die because of preventable error in hospitals alone. That is the equivalent of two jumbo jets crashing every day.

Another example is economics. In 2010, a group of influential thinkers, including Michael J Boskin, a former chairman of the US president’s Council of Economic Advisers, and the historian Niall Ferguson, wrote an open letter to the chairman of the Federal Reserve. The signatories were worried that a second tranche of quantitative easing would “risk currency debasement and inflation” and “distort financial markets”. The letter was published in the Wall Street Journal and New York Times.

At the time, inflation was running at 1.5 per cent, but what happened in the aftermath? Did inflation soar? In fact, by December 2014, inflation had not merely stayed at historically low levels, but had fallen to 0.8 per cent (soon after that, it fell into negative territory). The US economy was creating jobs at a fast rate, too, while unemployment had dropped and companies were reporting record profits.

This was a stark error in prediction, an opportunity to revise theoretical assumptions (just as mistakes in medicine provide an opportunity to revise procedures). But the signatories saw it differently. David Malpass, a deputy assistant secretary to the Treasury under Ronald Reagan, said “the letter was correct as stated”. John Taylor, an economics professor, said: “The letter mentioned many things – the risk of inflation . . . to employment . . . – and all have happened.”

Again, like revered clinicians, these prestigious thinkers could not bear that they had got things wrong. So, instead of learning from their mistake, they spun it. Some of the signatories came up with detailed graphs and tables to show that they were right all along.

Consider that if inflation had soared, they would have claimed this as a vindication for their prediction (as the cult members would have said the apocalypse had materialised). Yet these eminent thinkers also claimed vindication when inflation fell (just like the cult members when the spaceship didn’t turn up). Heads I win; tails I don’t lose.

And this is why it is the social pundits with the most prestigious reputations – as measured by how often they tour the television studios – who often make the worst predictions. They have the most to lose from mistakes and are therefore the most likely to come up with ex post explanations for why they were right all along. And because these pundits are clever, their rationalisations sound plausible.

But it is also why they don’t learn from their mistakes. After all, if you can’t admit when you are wrong, how can you ever put things right?


This brings us back to the criminal justice system. Many of these DNA cases show unequivocal failures. They demonstrate almost beyond doubt that mistakes were made by the police, prosecution and courts. This should have led to an acknowledgement of error, and meaningful reform. In fact, the astonishing thing is not that the system – or at least the people behind it – learned, but the extent to which it continued to evade and deny.

When the DNA results came back for Juan Rivera, state prosecutors offered a new story to account for the evidence – a very different story from the one that they had presented at the original trial. Holly, an 11-year-old child, had had consensual sex with a lover a few hours before the attack, prosecutors claimed. This accounted for the semen. And Rivera? He had happened upon Holly after intercourse had taken place, and murdered her.

“It was a grotesque way of squaring the new evidence with their unshakeable belief that Rivera was guilty,” Steven Art, one of the jailed man’s lawyers, told me. “But it was also totally inconsistent with the overwhelming evidence that Holly had been raped, quite brutally. There were signs of vaginal and anal trauma and stab wounds in her genitals.”

The prosecutor’s new story may have seemed outlandish, but the consequences were very real. Rivera was not released from prison for another six years. “I got stabbed twice and endured three attempted rapes,” he told me during a phone interview last year. “People wanted to hurt me; they thought that I was a child rapist. But perhaps the toughest thing of all was knowing that I was innocent.”

Rivera’s experience was far from unusual. The vast majority of exonerations through DNA evidence were met with breathtaking obstruction. Nothing seemed to budge prosecutors from their conviction that the man who had been sent to prison was guilty. Even after the test had been performed. Even after the conviction had been overturned. Even after the prisoner had been released from jail.

The problem was not the strength of the evidence, which was often overwhelming; it was the psychological difficulty in accepting it.

The process often took a distinctive path. First the prosecutors would try to deny access to DNA evidence. When that strategy was batted away, and the test excluded the convict as the source of the DNA, they would claim that it had not been carried out correctly. This didn’t last long, either, because when the test was redone it would invariably come back with the same result. The next stage in rape cases was for the prosecutor to argue that the semen belonged to a different man who was not the murderer. In other words, the victim had consensual sex with another man, but was subsequently raped by the prisoner, who used a condom.

The presence of an entirely new man, not mentioned at the initial trial, for whom there were no eyewitnesses, and who the victim often couldn’t remember having sex with, may seem like a desperate ploy to evade the evidence. But it has been used so often that it has been given a name by defence lawyers: “the unindicted co-ejaculator”.

In an adversarial system you would expect any new evidence secured by the defence to be looked at with healthy scepticism by prosecutors. You would expect them to give it scrutiny and to look at the wider context to be sure it stacks up. But in case after case, the sense of denial from prosecutors and police went a lot further.

And this explains, in turn, why the system was making so many mistakes. Proper investigation into wrongful convictions by the Innocence Project in recent years has discovered profound weaknesses in forensic science, police detection methods, eyewitness testimony and more. If these investigations had taken place earlier, and reforms been introduced, untold suffering could have been averted. But these opportunities were missed repeatedly, on both sides of the Atlantic.

This is why legal campaigners argue that the most robust way to improve the system, so as to reduce wrongful convictions and simultaneously increase rightful convictions, is to establish innocence commissions. These are independent bodies, mandated to investigate wrongful convictions and to recommend reforms, along the lines of air accident investigation teams. As of publication, only 11 states in the US had such commissions.

In the UK, a reform commission of sorts was set up in 1995 after a series of spectacular miscarriages of justice, including the Birmingham Six and the Guildford Four. The Criminal Cases Review Commission, an independent body, has the authority to refer questionable verdicts to the Court of Appeal. Between 1997 and the end of October 2013 it referred 538 cases in total.

Of these, 70 per cent succeeded at appeal.


More than 20 years after Juan Rivera was sentenced, a DNA test was conducted on a bloodstained piece of timber that had been used in a different murder. In January 2000, a man called Delwin Foxworth, who also lived in Lake County, was beaten savagely with a plank, doused with gasoline and set on fire. He died of his injuries, having suffered burns over 80 per cent of his body.

The DNA of the blood found on the wood matched that of the semen found in Holly Staker. Police are now almost certain that the man who got away with the rape and murder of an 11-year-old girl in 1992 went on to commit another murder eight years later. Foxworth may be yet another victim of the wrongful conviction of Juan Rivera; it allowed the real culprit to get away with it, and kill again. (The murderer has never been found.)

But what about those who were responsible for sending Rivera to jail? How do they feel about it today? Perhaps it should come as no surprise that even now many remain convinced of his guilt. In October 2014, Charles Fagan, an investigator who helped obtain Rivera’s confessions, was asked if he still believed that he committed the murder. “I think so,” he told a local newspaper.

And what of the prosecutors? Even after Rivera was released, Lake County lawyers wanted to put him back on trial. Only with a further conviction would they be able to say that they had been right all along. Only with a conviction could they quell their dissonance. Rivera walking around free was like an accusation against their competence.

It was left to the Illinois Appellate Court to take what might otherwise seem to be an astonishing step: it barred Lake County from ever prosecuting Juan Rivera for the murder of Holly Staker again.

Matthew Syed’s latest book is “Black Box Thinking: the Surprising Truth About Success” (John Murray)

This article first appeared in the 12 November 2015 issue of the New Statesman, Isis and the threat to Britain