The world is getting wider, says Charlotte Howard. What can be done about it?

Atmospheric governance

BACK in July a California businessman dumped 100 tonnes of an iron-containing chemical into the Pacific Ocean as an experiment in geoengineering. The aim of the project, which seems to have succeeded, was to generate a massive algae bloom. Algae sucks carbon dioxide out of the air as it grows, and may then sequester it away for centuries as it dies and sinks to the bottom of the ocean. The experiment was widely condemned by scientists and environmentalists who pointed out that the perpetrator violated international law. It seems probable, however, that the rogue bit of atmospheric tinkering is just the first of many unilateral geoengineering gambits.

In a new paper, economist Martin Weitzman outlines the nature of the problem:

This paper begins with the realization that there are really two diﬀerent externalities involved in the climate change problem, that they have near-opposite properties, that they interact, and that it seems diﬃcult to say oﬀhand which one is more threatening than the other. The ﬁrst externality, described by the above quotes, comes in the usual familiar form of a public goods problem whose challenge is enormous because so much is at stake and it is so diﬃcult to reach an international governing agreement that divides up the relatively expensive sacriﬁces that would be required by each nation to really make much of a dent in greenhouse gas (GHG) concentrations. The classic governance problem here is to limit the underprovision of a public good from free riding.

A second less-familiar externality shows up in the scary form of geoengineering the stratosphere with reﬂective particles to block incoming solar radiation. This geoengineeringtype externality is so relatively cheap to enact that it might in principle eﬀectively be undertaken unilaterally by one nation feeling itself under climate siege, to the detriment of other nations. The challenge with this second global externality also appears to be enormous, because here too so much is at stake and it also seems diﬃcult to reach an international governing agreement. If the ﬁrst externality founders on the “free rider” problem of underprovision, then the second externality founders on what might be called the “free driver” problem of overprovision. If the ﬁrst externality is the “mother of all externalities,” then the second externality might be called the “father of all externalities.” These two powerful externalities appear to be almost polar opposites, between which the world is trapped.

There are several arguments made against the strategy of simply reducing emissions as a primary method of combating climate change. One is that reducing emissions by the amount necessary to prevent significant climate change would simply be too costly to win public support (in the absence of major research breakthroughs). Another, however, is that coordinating emission reductions across the whole of the world's nearly 200 countries is critical to the success of the policy—big reductions in America and Europe won't matter much if emissions grow relentlessly across the emerging world, for instance—and such international coordination is very difficult to imagine. It would require agreement on targets and mechanisms for penalising shirking countries. The world has had some success with coordination of this nature, in averting wars, for example, and in policing and liberalising trade. But those efforts have been decades in the making—time we lack.

What seems increasingly important to understand, however, is that the need for international cooperation will be if anything more serious in a world that doesn't act to control emissions (or control emissions enough to prevent substantial warming). From a pure adaptation standpoint, migration flows are sure to be enormous and potentially destabilising, but also represent one of the very best ways to reduce the human and economic costs of climate change. In the absence of coordination, relatively open countries may be swamped and may restrict immigration even more as a result, intensifying flows to other relatively open countries until openness to migrants across the world is significantly reduced.

Just as serious a concern, however, is that pressure for geoengineering solutions will grow as the effects of warming intensify. Large, northerly countries like Canada and Russia have an almost unchecked ability to adapt but smaller and more equatorial places will quickly run out of options. It is unrealistic to suppose that unilaterial geoengineering schemes won't be an inevitable result.

Such schemes could pose huge risks. Successful, precisely deployed efforts might nonetheless have unpredictable and substantial side effects or unpleasant distributional costs. Without a forum to address such effects, geopolitical tensions could worsen in a hurry. Even more frightening, uncoordinated efforts could be too successful, flipping earth from a warming scenario to a dangerously cold one.

People have been engineering the climate in very aggressive fashion for more than a century now. We have made ourselves atmospheric managers, and there is no going back. If the world can't create a functional international forum for addressing atmospheric management—one with teeth—then the costs of global warming are going to be far higher than they ought to be, whatever the mix of policies used to attack it.

The big picture

The world is getting wider, says Charlotte Howard. What can be done about it?

IT IS LUNCHTIME at Eastside Elementary School in Clinton, Mississippi, the fattest state in the fattest country in the Western world. Uniformed lunch ladies stand at the ready. Nine-year-olds line up dutifully, trays in hand. Yes to chocolate milk, yes to breaded chicken sandwiches, yes to baked beans, yes to orange jelly, no to salad. Bowls of iceberg lettuce and tomatoes sit rim to rim, rejected. Regina Ducksworth, in charge of Clinton’s lunch menu, sighs. “Broccoli is very popular,” she says, reassuringly.

Persuading children to eat vegetables is hardly a new struggle, nor would it seem to rank high on the list of global priorities. In an age of plenty, individuals have the luxury of eating what they like. Yet America, for all its libertarian ethos, is now worrying about how its citizens eat and how much exercise they take. It has become an issue of national concern.

Two-thirds of American adults are overweight. This is defined as having a body mass index (BMI, a common measure of obesity) of 25 or more, which for a man standing 175cm (5’9”) tall means a weight of 77kg (170 pounds) or more. Alarmingly, 36% of adults and 17% of children are not just overweight but obese, with a BMI of at least 30, meaning they weigh 92kg or more at the same height. If current trends continue, by 2030 nearly half of American adults could be obese.

Americans may be shocked by these numbers, but for the rest of the world they fit a stereotype. Hamburgers, sodas and sundaes are considered as American as the Stars and Stripes. Food at state fairs is American cuisine at its most exuberantly sickening. At the Mississippi fair, a deep-fried Oreo biscuit’s crispy exterior gives way to soft dough, sweet cream and chocolate goo. It is irresistible.

The rest of the world should not scoff at Americans, because belts in many other places are stretched too, as shown by new data from Majid Ezzati of Imperial College, London, and Gretchen Stevens of the World Health Organisation (WHO). Some continental Europeans remain relatively slender. Swiss women are the slimmest, and most French women don’t get fat, as they like to brag (though nearly 15% do). But in Britain 25% of all women are obese, with men following close behind at 24%. Czech men take the European biscuit: 30% are obese.

And it is not just the rich world that is too big for its own good. The world’s two main hubs for blub are the Pacific islands and the Gulf region. Mexican adults are as fat as their northern neighbours. In Brazil the tall and slender are being superseded by the pudgy, with 53% of adults overweight in 2008. Even in China, which has seen devastating famine within living memory, one adult in four is overweight or obese, with higher rates among city-dwellers. In all, according to Dr Ezzati, in 2008 about 1.5 billion adults, or roughly one-third of the world’s adult population, were overweight or obese. Obesity rates were nearly double those in 1980.

Fat of the land

Not long ago the world’s main worry was that people had too little to eat. Malnourishment remains a serious concern in some regions: some 16% of the world’s children, mainly in sub-Saharan Africa and South Asia, were underweight in 2010. But 20 years earlier the figure was 24%. In a study of 36 developing countries, based on data from 1992 to 2000, Barry Popkin of the University of North Carolina found that most of them had more overweight than underweight women.

The clearest explanation of this extraordinary modern phenomenon comes from a doctor who lived in the 5th century BC. “As a general rule,” Hippocrates wrote, “the constitutions and the habits of a people follow the nature of the land where they live.” Men and women of all ages and many cultures did not choose gluttony and sloth over abstemiousness and hard work in the space of just a few decades. Rather, their surroundings changed dramatically, and with them their behaviour.

Much of the shift is due to economic growth. BMI rises in line with GDP up to $5,000 per person per year, then the correlation ends. Greater wealth means that bicycles are abandoned for motorbikes and cars, and work in the fields is swapped for sitting at a desk. In rich countries the share of the population that gets insufficient exercise is more than twice as high as in poor ones.

Very importantly, argues Boyd Swinburn of Deakin University in Melbourne, diets change. Families can afford to eat more food of all kinds, and particularly those high in fat and sugar. Mothers spend more time at work and less time cooking. Food companies push their products harder. Richard Wrangham of Harvard University says that heavily processed food may have helped increase obesity rates. Softer foods take less energy to break down and finely milled grains can be digested more completely, so the body absorbs more calories.

These global changes react with local factors to create different problems in different regions. Counter-intuitively, in some countries malnutrition is leading to higher obesity rates. Undernourished mothers produce babies who are predisposed to gaining weight easily, which makes children in fast-developing countries particularly prone to getting fat.

In Mexico unreliable tap water and savvy marketing have helped make the country the world’s leading guzzler of Coca-Cola: the average adult consumed 728 servings last year. In America junk-food calories are often cheaper than healthy ones. Suburban sprawl and the universal availability of food have made the car the new dining room. In the Middle East, Bedouin traditions of hosting and feasting have combined with wealth to make overeating a nightly habit. Any inclination to exercise is discouraged by heat and cultural restrictions. In Beijing teenagers and office workers cram the fast-food restaurants along Wangfujing. Even home-cooked Chinese meals contain more meat and oil than they used to. Doting grandparents shower edible treats on scarce grandchildren.

Together, these disparate changes have caused more and more people to become fat. Many cultures used to view a large girth with approval, as a sign of prosperity. But obesity has costs. It lowers workers’ productivity and in the longer term raises the risk of myriad ailments, including diabetes, heart disease, strokes and some cancers; it also affects mental health. In America, obesity-related illness accounted for one-fifth of total health-care spending in 2005, according to one paper.

A huge new global health study, led by Christopher Murray of the University of Washington, shows that since 1990 obesity has grown faster than any other cause of disease. For women a high BMI is now the third-largest driver of illness. At the same time childhood mortality has dropped and the average age of the world’s population has risen rapidly. In combination these trends may mark a shift in public-health priorities. Increasingly, early death is less of a worry than decades spent alive and sick.

It is plain that obesity has become a huge problem, that the factors influencing it are fiendishly hard to untangle and that reversing it will involve difficult choices. Radical moves such as banning junk food would infringe individuals’ freedom to eat what they like. Instead, some governments are cautiuosly prodding their citizens to eat less and exercise more, and food companies are offering at least some healthier foods.

In a few places obesity rates seem to be levelling, but for now waistlines in most countries continue to widen unabated. Jiang He and his colleagues at Tulane University have estimated that by 2030 the global number of overweight and obese people may double to 3.3 billion. That would have huge implications for individuals, governments, employers, food companies and makers of pharmaceuticals.

The Higgs boson

Double trouble

AS DISCOVERIES go, that of the Higgs boson is as big as they get. Much of modern physics hinges on the particle, first predicted 48 years ago by Peter Higgs, a Briton, and independently by two other teams of theorists, and finally observed earlier this year at CERN, Europe's main particle-physics laboratory, outside Geneva (earning the seven leading experimenters a $3m prize earlier this week from a Russian internet mogul). Paradoxically, however, many boffins would rather Dr Higgs's prediction not be borne out to the letter. The latest results from ATLAS, one of the two experiments spearheading the Higgs hunt at CERN, offers the contrarians a glint of hope.

The reason the Higgs is imperative is that without it, or something like it, to give mass to other particles, the entire elaborate mathematical edifice erected over the past four decades to describe the most fundamental constituents of reality would topple. The reason many physicists would prefer it to differ from what Dr Higgs and the others postulated is that this would give them an inkling of where the successor to the Standard Model, as that venerable theory is known, might be hiding.

For all its explanatory power, the Standard Model leaves some big questions, like why the universe is made of matter, unanswered. Theorists have plenty of ideas which explain everything the model does, and more. But if observations conform precisely to its predictions, they have no way of telling which of these ideas reflects reality. For that, they need data at odds with the reigning theory.

On December 13th ATLAS obliged—sort of. An unstable beast, the Higgs cannot be observed directly. Instead, physicists look for telltale patterns left in the detector by longer-lived particles it decays into. Theory allows for a number of distinct decay modes, as the patterns are called. For example, the Higgs can break up into two photons or into two heavier particles called Z bosons, among other possibilities. By measuring the energy of these daughter particles, scientists can, by dint of Albert Einstein's famous equation E=mc², work backwards to determine the mass of the parent. When ATLAS researchers did this with their latest batch of data, instead of both modes pointing to the same mass of around 125 giga-electron-volts (GeV), the esoteric unit used to weigh subatomic particles, they yielded two, slightly different masses: 123.5GeV for the Zs and 126.6Gev for the photons.

The difference is about three times the ATLAS detector's resolution of 1GeV or so. The odds that the result is down to chance are around one in 100, well below the exacting one-in-3.5m standard particle physicists have set themselves to claim a discovery, but enough to stoke speculation.

ATLAS scientists are doing their utmost to cool any excitement. For one thing, although some theoretical proposals imply the existence of more than one Higgs, it would be quite a coincidence for their masses to be so close together. Odder still would be the two Higgses' preference for distinct daughters; theorists expect any Higgs-like particle to display either both decay modes, or neither.

Crucially, CERN's other big Higgs-hunting experiment, called CMS, is not seeing double. Its data indicate a single Higgs mass of 126GeV. Indeed, for all decay modes taken together, so do ATLAS's. In all likelihood, then, the discrepant result is an artefact, caused by the limited precision of the apparatus or a fluke of statistics.

Still, physicists will draw subversive comfort from another piece of information which emerged from both experiments this week. Besides enumerating the possible decay modes, the Standard Model makes firm predictions about how often the different patterns ought to occur. For break-up into Z bosons, as well as for some other analysed patterns, the data dovetail neatly with theory. But the rate for the decay into two photons is consistently higher than expected. If this were due to a statistical fluctuation, you would expect the effect to diminish with more data. Instead, it refuses to budge. This, too, might be mere statistical noise. But many boffins are keeping their fingers crossed that it is the first note of a whole new symphony.

Lifting the burden