Hot and bothered
LOOKING BACK FROM the early 24th century, Charlotte Shortback suggests, half-jokingly, that modern human history can be split into distinct periods. The most exciting was the Accelerando, from about 2160 to 2200, when human lifespans were greatly extended and the terraforming of Mars was completed. That was followed by the Ritard, when the people of Mars lapsed into isolationism. Long before, though, came a strange spell, from 2005 to 2060, when people understood the science of climate change but did little to prevent it; nor did they try to colonise other planets. She dubs it the Dithering. Charlotte Shortback is a character in 2312, a science-fiction novel by Kim Stanley Robinsonone of an oddly small band of authors who have written imaginatively and precisely about climate change. In his fictional future, global warming has turned the Earth into a wet, jungle-like planet. New York City is 11 metres under water. In other places, desperate efforts are under way to hold glaciers in place with liquid nitrogen and dams. Will the world really turn out this way? Almost certainly not: strict accuracy is neither the strength nor the purpose of science fiction. But Mr Robinson is right about the present. What is happening today might not seem like dithering. In a few days world leaders will gather in Paris for a grand conference on climate change, the 21st such get-together since the United Nations began to grapple with the issue. A torrent of pronouncements and promises has already issued forthfrom Pope Francis, Xi Jinping, Barack Obama and many others. The IMF warns that human fortunes will evaporate like water under a relentless sun if climate change is not checked soon. Especially in western Europe, but increasingly in America and China too, wind turbines and fields full of solar photovoltaic panels are becoming familiar features of the landscape. If you buy a car or a house in Europe, or even book a hotel room, you may well be told about its cost in carbon. Many companies, including The Economist Group, monitor their carbon-dioxide emissions and often set targets to reduce them. There is gleeful talk of coal, oil and gas falling from favour so quickly that energy firms will be left sitting on heaps of stranded assets. None of this, however, amounts to much. At the time of the first UN climate-change conference in 1995, the atmospheric concentration of carbon dioxide was 361 parts per million. Last year it reached 399 parts per million. Between 2000 and 2010 the rise in greenhouse-gas emissions was even faster than in the 1980s or 1990s. The hottest year since records began was 2014; average surface air temperatures so far this decade are about 0.9C higher than they were in the 1880s. Dieter Helm, an energy expert at Oxford University, points to a quarter of a century of nothing of substance being achieved. The International Energy Agency, a think-tank, estimates that 13.5% of the worlds primary energy supply was produced from renewable sources in 2013. That sounds like a decent slice, but almost three-quarters of this renewable energy came from what are euphemistically known as biofuels. This mostly means burning wood, dung and charcoal in poor countries. Hydro-electric power, which has fallen from favour in the West because of its often ruinous effect on river ecosystems, was the worlds second most important source of renewable energy. Nuclear power, which is green but not renewable, supplied 5% of energy needs, and falling. Wind turbines, solar farms, tidal barriers, geothermal power stations and the like produced just 1.3% between them. The global effort to tackle climate change by imposing caps on countries greenhouse-gas emissions, which until recently was described as essential for saving the planet, is over. The UNs boldest attempt to bind countries, the Kyoto protocol of 1997, expired in 2012. It had achieved little and become unworkable; its passing was not much lamented. No ambitious global deal will be signed in Paris, although whatever document emerges from the conference will no doubt be hailed as significant progress. Rather than submitting themselves to caps, most countries now say they intend to reduce, or at least restrain, their own emissions. This fragmented, voluntary approach avoids the debate that had paralysed climate talks for years, about whether the burden of cutting greenhouse gases should be carried just by the rich world or spread more widely (a debate rendered absurd by the rise of China). It has the advantage of inclusiveness. Outside the oil-rich Middle East, which is mostly ignoring the process, countries are at least thinking about what they could do. The promises they will bring to Paris, known as intended nationally determined contributions, are diverse and hard to compare. Still, some are plainly more ambitious than others. America pledges that by 2025 it will cut its greenhouse-gas emissions by 26-28% below 2005 levels. South Korea says that by 2030 its emissions will be 37% below where they would be if the recent upward trend in emissions were projected forward. But even if it manages this, South Korea will be emitting 81% more greenhouse gases in 2030 than it did in 1990. On one matter the conference delegates have already agreed: global temperatures must not be allowed to rise by more than 2C (3.6F) above pre-industrial levels. Politicians and green groups have argued for years that anything more would be wildly dangerous. Almost every book and report about climate change treats this limit as inviolable. A question of degree Barring a global catastrophe or the spectacular failure of almost every climate model yet devised, though, emissions of greenhouse gases will warm the world by more than 2C. Its nice for people to talk about two degrees, says Bill Gates, a philanthropist and investor. But we dont even have the commitments that are going to keep us below four degrees of warming. Changes in the atmospheric level of carbon dioxide, the biggest contributor to global warming, persist for centuries. So it is useful to imagine that mankind has a fixed carbon budget to burn through. Pierre Friedlingstein, a climatologist at Exeter University, calculates that if temperature rises are to be kept below 2C, the world can probably emit about 3,200 gigatonnes of carbon dioxide in total. The tally so far is 2,000 gigatonnes. If annual emissions remain at present levels, the budget will be exhausted in just 30 years time. Global greenhouse-gas emissions might indeed hold steady for a while. Total man-made emissions in 2014 were about the same as in 2013, according to the International Energy Agency. This years figure could even be slightly lower than last years. As this special report will show, the pause has little to do with the forests of wind turbines and solar panels that have popped up in Western countries, and much to do with developments in China. Still, given the steep rise in greenhouse-gas emissions in recent years (see chart), it is welcome. The bad news is that even if greenhouse-gas emissions are stabilising, they are doing so at an exalted level, and there is little reason to suppose that the plateau will be followed by a downward slope. China might burn a little less coal in the next few years, but India will burn moreand the Chinese will drive more cars. A lot of poor countries are going to get a lot richer by burning fossil fuels, predicts Bjorn Lomborg of the Copenhagen Consensus Centre, a think-tank. Rich countries will continue to become cleaner, but not dramatically so, at least when the carbon content of the goods they import is added to the reckoning. Climate change will not be bad for everything and everyone. Some cold countries will find that their fields can grow more crops; others will see fish migrate into their waters. With its ocean-moderated climate, Britain stands out as exceptionally favoured. Yet bad effects will increasingly outnumber benign ones almost everywhere. Some organisms will run into trouble well before the 2C limit is breached. This special report will argue that climate change will have to be tackled more intelligently and more economically than it has been so far. Renewable energy is crucial. Contrary to what many claim, though, it is not true that existing solar and wind technologies could cheaply save the planet while also creating lots of green jobs if only they were subsidised for just a few more years. Those renewable power sources have cost consumers dear and mangled energy markets. Paying for yet more wind turbines and solar panels is less wise than paying for research into the technologies that will replace them. Mankind will also have to think much more boldly about how to live under skies containing high concentrations of greenhouse gases. It will have to adapt, in part by growing crops that can tolerate heat and extreme weather, in part by abandoning the worst-affected places. Animals and plants will need help, including transporting them across national and even continental boundaries. More research is required on deliberately engineering the Earths atmosphere in order to cool the planet. It is often said that climate change is an urgent problem. If that were true, it might be easier to tackle. In fact it is a colossal but slow-moving problem, spanning generations. As the next article will show, it is also rather wonderfully mysterious.