Has global warming really stopped?

Mark Lynas responds to a controversial article on newstatesman.com which argued global warming has s

On 19 December the New Statesman website published an article which, judging by the 633 comments (and counting) received so far, must go down in history as possibly the most controversial ever. Not surprising really – it covered one of the most talked-about issues of our time: climate change. Penned by science writer David Whitehouse, it was guaranteed to get a big response: the article claimed that global warming has ‘stopped’.

As the New Statesman’s environmental correspondent, I have since been deluged with queries asking if this represents a change of heart by the magazine, which has to date published many editorials steadfastly supporting urgent action to reduce carbon emissions. Why bother doing that if global warming has ‘stopped’, and therefore might have little or nothing to do with greenhouse gas emissions, which are clearly rising?

I’ll deal with this editorial question later. First let’s ask whether Whitehouse is wholly or partially correct in his analysis. To quote:

"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."

I’ll be blunt. Whitehouse got it wrong – completely wrong. The article is based on a very elementary error: a confusion between year-on-year variability and the long-term average. Although CO2 levels in the atmosphere are increasing each year, no-one ever argued that temperatures would do likewise. Why? Because the planet’s atmosphere is a chaotic system, which expresses a great deal of interannual variability due to the interplay of many complex and interconnected variables. Some years are warmer and cooler than others. 1998, for example, was a very warm year because an El Nino event in the Pacific released a lot of heat from the ocean. 2001, by contrast, was somewhat cooler, though still a long way above the long-term average. 1992 was particularly cool, because of the eruption of a large volcano in the Philippines called Mount Pinatubo.

‘Climate’ is defined by averaging out all this variability over a longer term period. So you won’t, by definition, see climate change from one year to the next - or even necessarily from one decade to the next. But look at the change in the average over the long term, and the trend is undeniable: the planet is getting hotter.

Look at the graph below, showing global temperatures over the last 25 years. These are NASA figures, using a global-mean temperature dataset known as GISSTEMP. (Other datasets are available, for example from the UK Met Office. These fluctuate slightly due to varying assumptions and methodology, but show nearly identical trends.) Now imagine you were setting out to write Whitehouse’s article at some point in the past. You could plausibly have written that global warming had ‘stopped’ between 1983 and 1985, between 1990 and 1995, and, if you take the anomalously warm 1998 as the base year, between 1998 and 2004. Note, however, the general direction of the red line over this quarter-century period. Average it out and the trend is clear: up.

Note also the blue lines, scattered like matchsticks across the graph. These, helpfully added by the scientists at RealClimate.org (from where this graph is copied), partly in response to the Whitehouse article, show 8-year trend lines – what the temperature trend is for every 8-year period covered in the graph.

You’ll notice that some of the lines, particularly in the earlier part of the period, point downwards. These are the periods when global warming ‘stopped’ for a whole 8 years (on average), in the flawed Whitehouse definition – although, as astute readers will have quickly spotted, the crucial thing is what year you start with. Start with a relatively warm year, and the average of the succeeding eight might trend downwards. In scientific parlance, this is called ‘cherry picking’, and explains how Whitehouse can assert that "since [1998] the global temperature has been flat" – although he is even wrong on this point of fact, because as the graph above shows, 2005 was warmer.

Note also how none of the 8-year trend lines point downwards in the last decade or so. This illustrates clearly how, far from having ‘stopped’, global warming has actually accelerated in more recent times. Hence the announcement by the World Meteorological Organisation on 13 December, as the Bali climate change meeting was underway, that the decade of 1998-2007 was the “warmest on record”. Whitehouse, and his fellow contrarians, are going to have to do a lot better than this if they want to disprove (or even dispute) the accepted theory of greenhouse warming.

The New Statesman’s position on climate change

Every qualified scientific body in the world, from the American Association for the Advancement of Science to the Royal Society, agrees unequivocally that global warming is both a reality, and caused by man-made greenhouse gas emissions. But this doesn’t make them right, of course. Science, in the best Popperian definition, is only tentatively correct, until someone comes along who can disprove the prevailing theory. This leads to a frequent source of confusion, one which is repeated in the Whitehouse article – that because we don’t know everything, therefore we know nothing, and therefore we should do nothing. Using that logic we would close down every hospital in the land. Yes, every scientific fact is falsifiable – but that doesn’t make it wrong. On the contrary, the fact that it can be challenged (and hasn’t been successfully) is what makes it right.

Bearing all this in mind, what should a magazine like the New Statesman do in its coverage of the climate change issue? Newspapers and magazines have a difficult job of trying, often with limited time and information, to sort out truth from fiction on a daily basis, and communicating this to the public – quite an awesome responsibility when you think about it. Sometimes even a viewpoint which is highly likely to be wrong gets published anyway, because it sparks a lively debate and is therefore interesting. A publication that kept to a monotonous party line on all of the day’s most controversial issues would be very boring indeed.

However, readers of my column will know that I give contrarians, or sceptics, or deniers (call them what you will) short shrift, and as a close follower of the scientific debate on this subject I can state without doubt that there is no dispute whatsoever within the expert community as to the reality or causes of manmade global warming. But even then, just because all the experts agree doesn’t make them right – it just makes them extremely unlikely to be wrong. That in turn means that if someone begs to disagree, they need to have some very strong grounds for doing so – not misreading a basic graph or advancing silly conspiracy theories about IPCC scientists receiving paycheques from the New World Order, as some of Whitehouse’s respondents do.

So, a mistaken article reached a flawed conclusion. Intentionally or not, readers were misled, and the good name of the New Statesman has been used all over the internet by climate contrarians seeking to support their entrenched positions. This is regrettable. Good journalism should never exclude legitimate voices from a debate of public interest, but it also needs to distinguish between carefully-checked fact and distorted misrepresentations in complex and divisive areas like this. The magazine’s editorial policy is unchanged: we want to see aggressive action to reduce carbon emissions, and support global calls for planetary temperatures to be stabilised at under two degrees above pre-industrial levels.

Yes, scientific uncertainties remain in every area of the debate. But consider how high the stakes are here. If the 99% of experts who support the mainstream position are right, then we have to take urgent action to reduce emissions or face some pretty catastrophic consequences. If the 99% are wrong, and the 1% right, we will be making some unnecessary efforts to shift away from fossil fuels, which in any case have lots of other drawbacks and will soon run out. I’d hate to offend anyone here, but that’s what I’d call a no-brainer.

Mark Lynas has is an environmental activist and a climate change specialist. His books on the subject include High Tide: News from a warming world and Six Degree: Our future on a hotter planet.
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Chill out

Stress is not as destructive as is often assumed: a little bit of it may even be good for us.

It creeps up on you as soon as the alarm clock rings. Fingers reflexively unlock your phone. Emails bound in with a jolly ping: things you should have done last week; pointless meeting requests; bills to pay.

Over a hurried breakfast you scan the headlines: wall-to-wall misery. On the train you turn to social media for relief. ­Gillian is funnier than you. Alex got promoted again. Laura’s sunning herself in Thailand. You’re here, packed in, surrounded but alone, rattling your way towards another overstretched day.

Stress: we know what it feels like, we can smell it on others, we complain about it most days. And we’re living through an epidemic of it. The government’s Health and Safety Executive estimates that stress cost the economy nearly ten million working days last year. Some 43 per cent of all sick days were attributed to stress. In the US, a large survey conducted by the National Public Radio network in 2014 showed that nearly one in two people reported a major stress event at some point in the previous 12 months. The year before that, American doctors wrote 76 million unique prescriptions for the anti-anxiety drugs Xanax and Ativan. With the media running stories about stress-induced heart disease, strokes, obesity, depression, ulcers and cancer, it’s hard not to conclude that stress kills.

But consider this: just a century ago, nobody got stressed. They suffered with their nerves, got a touch of the vapours; they worried; but they were never stressed. In fact, our current view of stress – what it is, what it feels like, and when it is harmful – evolved surprisingly recently. And research shows that the way we think about stress has a profound influence on how it affects us.

Prolonged, uncontrollable stress – particularly if suffered in childhood – can be profoundly corrosive and debilitating. But what of the familiar stresses of day-to-day life? Are they actually damaging you? Might the belief that stress is harmful be self-fulfilling? And what would a stress-free life look like? Instead of turning in on ourselves and doing battle with our personal stress demons, might we be able to put their diabolic energy to good use?

If we pause for a moment from our daily hustle we would see that many of us are incurably hooked on stress. We thrive on it, getting a kick out of surviving the high-stakes presentation, meeting the deadline and overcoming our fears and prejudices. Watching a thriller, we are on the edge of our seat, pulses racing. Sports, on the field or on television, can propel us into “fight or flight” mode. Humanity’s fascination with gambling hinges on stress.

If the most skilled physiologists in the world could peer beneath the skin of a thrill-seeker on a roller coaster and an out-of-his-depth job interview candidate, they would struggle to tell them apart. Deep in the brain, they would see a structure called the hypothalamus fired up. With each lurch of the ride or disarming question asked, the hypothalamus signals to the adrenal glands, which sit atop each kidney. The adrenals then squirt a shot of adrenalin into the bloodstream. In the background, the hypothalamus prods the pituitary gland, which passes a different message on to the adrenal gland. This increases production of cortisol, the textbook “stress hormone”. Flipping these biological switches triggers the familiar bodily symptoms of stress: a pounding heart, raised blood pressure, dilated pupils, arrested digestion and a damped-down immune system. In both cases, the biological stress response would look very similar.

Even if we could eliminate stress entirely, or smother it with pharmaceuticals, we wouldn’t want to. To muzzle the stress response is to silence the good as well as the bad. At best, stress can motivate us to achieve more and fix the sources of our stress. Boredom is stressful in its own way: observe a caged lion, or an understimulated teenager. In fact, as the animal psychologist Françoise Wemelsfelder told New Scientist recently, boredom may exist to spur us back into activity. This half-forgotten idea, that some degree of stress can inspire and elevate, is common sense. It also has deep roots in the earliest scientific study of stress and stress responses.

***

At the beginning of the 20th century, two American psychologists, Robert Yerkes and John Dodson, wanted to know how stressing out lab mice affected their learning. They set the rodents navigational challenges and punished wrong turns by administering small electric shocks to the feet. In their terminology, larger electric currents caused greater “arousal”.

They spotted some consistent trends. When they gave mice an easy task (choosing between a black or a white tunnel) the relationship between the strength of the shock and the speed of learning was simple. The greater the stressor, the quicker the mice learned to pick the right tunnel.

When the challenge was subtler (differentiating between grey tunnels), the response was less straightforward. Weak shocks provided little impetus to learn, but as the zaps got stronger, the mice gradually upped their game. They focused on the task and remembered the consequences of wrong choices. Yet, at a certain point, the high stress levels that helped with the easy task became counterproductive. Overwhelmed, the mice skittered around at random, trying in vain to escape.

On a graph, the relationship between stress and performance on onerous tasks traces an inverted U shape. Some degree of stress helps, but there is a clear tipping point, beyond which stress becomes paralysing. The findings became known as the Yerkes-Dodson law.

This was all very well for mice, but could it be applied to human beings? According to the Canadian-Austrian endocrinologist Hans Selye, the “father of stress”, it could. Selye was the first person to describe the key glands, hormones and nerves of the biological stress response during the 1930s and 1940s, and also one of the first to apply the word “stress” to human biology.

For Selye, “stress” described an all-purpose response the body had to any demand placed upon it. When stress is on the upswing of Yerkes and Dodson’s inverted-U performance curve, Selye calls it “eustress”. This is where good teachers and managers should push their charges: to the sweet spot that separates predictable tedium from chaotic overload. Where stress gets more persistent, unmanageable and damaging, Selye calls it “distress”. Eustress and distress have identical biological bases; they are simply found at different points on the same curve.

Despite this knowledge, stress has a terrible public image today, often synonymous with distress. While some wear their stress as a badge of honour (“I’m important enough to be stressed”), deep down even the most gung-ho City workers probably stress about their stress. And in painting stress as a beast, we grant it more destructive power.

When did we come to view stress as the universal enemy? Mark Petticrew, Professor of Public Health Evaluation at the London School of Hygiene and Tropical Medicine, has sifted through a huge archive of historical tobacco industry documents. In a 2011 paper, he revealed that a large proportion of stress research during the second half of the 20th century was funded, steered and manipulated by this most unexpected of benefactors. Indeed, from the late 1950s, Hans Selye received hundreds of thousands of tobacco-stained dollars. He also allowed industry lawyers to vet his research and appeared in several pro-tobacco propaganda films.

“They put a massive, massive amount of money into it,” Petticrew told me.

Why were tobacco manufacturers so interested in stress? First, cigarettes were marketed as a stress reliever. “To anxiety . . . I bring relief,” reads a 1930s advertisement for Lucky Strike. So if research could help them pin poor mental and physical health to stress, this sort of message would carry more weight. (Incidentally, the still widespread belief that smoking reduces anxiety appears to be wrong.)

Later, as evidence grew that smoking caused cancer and heart disease, the tobacco industry wanted to prove that stress was an equally significant risk factor. They used the authority of Selye and several other leading researchers as a smokescreen. “Doubt is our product,” read a top industry executive’s 1969 memo. And so doubt they sowed, arguing repeatedly that stress was a major cause of disease. Those seeking to control tobacco were wrong, they claimed.

It worked: the industry convinced the general public of the evils of stress and diverted public health research for at least a decade. With tobacco regulation and compensation payouts postponed, the profits kept rolling in.

Should we doubt the veracity and neutrality of all the foundational research into stress as a disease? “I wouldn’t want to argue that stress doesn’t exist, or that it isn’t bad for your health and certainly your mental health,” Petticrew says. “But you can’t ignore this story.”

He goes on to describe concrete “findings” that industry-funded researchers got wrong. Prominent among these was a link between coronary disease and people displaying so-called Type A personality traits: competitiveness, ambition, anxiety. Such temperamentally “stressed” people were especially likely to suffer heart attacks and, not coincidentally, to smoke. Then the association faded away. “Aside from the scientific weaknesses, which are many, Type A is a cultural artefact to some extent constructed by the tobacco lobby,” Petticrew says. And yet, despite its fragile foundations, the Type A myth persists today.

The long shadow cast by decades of one-sided, propaganda-laced stress research has led many people to believe that stress is a direct cause of heart attacks. But the British Heart Foundation’s website states, “There is no evidence to suggest that stress causes coronary heart disease or heart attacks.” Nor does it cause stomach ulcers: usually it is a bacterium called Helicobacter pylori which does that.

The tobacco-funded researchers didn’t get it all wrong. Stress does have clear causal links to some diseases, particularly mental illnesses, including depression, anxiety disorders, schizophrenia and addictive behaviour. High stress levels appear to be a general risk factor for early death, among middle-aged men in particular. Moreover, we all know how unpleasant stress can be. From insomnia to binge eating and boozing, we respond to stress with all sorts of counterproductive and antisocial behaviours. And that is partly why the tone of messages we hear about stress matters so much. Human beings are inherently suggestible and particularly vulnerable to warning messages about our health, especially when those messages seem to be backed by science.

***

With mice in a cage, you can measure the tipping point – the precise current of the electric shock – where good stress becomes bad. But we don’t need the lurking menace of a lion in the long grass to activate our stress response. We can do it perfectly well for ourselves. All it takes is a negative thought, the memory of an insult, or a vague feeling of unease.

We can think our way into stress. And, as recent evidence shows, if we believe stress is going to hurt us, it is more likely to hurt us. This is one message emerging from the Whitehall II project, a long-term study of 10,000 UK government civil servants, set up in 1985 to study the social, economic and personal determinants of health and disease. A 2013 analysis of Whitehall II data concluded that people who believe stress adversely affects their health are more than twice as likely to suffer a heart attack, irrespective of their stress levels.

There is a flipside to this gloomy news. If our thoughts and beliefs can switch on a damaging stress response, can they also switch it off? Could the power of suggestion be a partial vaccination in the battle against the stress epidemic?

This is the contention of Alia Crum, a psychology professor at Stanford University and a flagbearer for the science of mindset manipulations. In 2007 she showed that if hotel chambermaids come to think of their work as exercise, they lose weight and their blood pressure falls, apparently without them working any harder. More recently, she described how UBS bankers who were shown videos about the life-enhancing effects of stress – how it can sharpen attention, boost cognition and force fresh perspectives – reported being more productive, focused and collaborative, and less afflicted by depression and anxiety.

The inescapable conclusion is this: the human mind is a powerful gatekeeper to the stress response. But we have to tread carefully here. UBS employees may have the freedom to choose a less stressful life, and find opportunity to reshape their stress mindsets. What about those whose stress is delivered early and compounded by a lifetime of disadvantage and adversity? Perhaps this is where the story of familiar, workaday stress and the grinding strain of social injustice come together. Stress gets under our skin only when we can’t see the end or spot the fix. So what, other than using Crum’s mindset interventions, can we do to restore the critical feeling of empowerment?

Emily Ansell, an assistant professor of psychiatry at Yale, says that reaching out a kindly hand to your fellow human beings can be surprisingly helpful. In a study published last year, Ansell and colleagues gave a group of 77 people a diary-like smartphone app. They asked the subjects to record all the stressful incidents they encountered, and any minor acts of kindness they performed, during a 14-day period. The data shows that gestures such as holding doors for strangers and helping elderly people across the road buffer the effects of stress and make you feel more optimistic.

Positive interactions deliver a reward at the neurological level. They restore a sense of control and show that meaningful relationships are possible. Moreover, helpers often get more psychological and health benefits than those on the receiving end of  that help.

How do we encourage prosocial behaviour throughout society, particularly at the margins? According to Paul Piff, a social psychologist at the University of California, Irvine, lower-class people in America often “have less and give more”. They are more generous, charitable, trusting and helpful than their upper-class counterparts. It’s possible that this tendency to reach out and muck in is a direct response to a life of chronic stress. In response to Piff’s theory, Michael Poulin, a professor of psychology at the University of Buffalo, suggests: “We should perhaps really focus on encouraging prosocial behaviour among the well-off, ­potentially leading to benefits both for them – in terms of stress – and for the disadvantaged, who would presumably benefit from their generosity.”

This article is published simultaneously in the Long + Short, the free online magazine of ideas published by Nesta, the UK’s innovation foundation. thelongandshort.org

This article first appeared in the 19 May 2016 issue of the New Statesman, The Great Huckster