reading

‘The Burning Question is a fascinating examination of the forces that have led to our current predicament and it presents an important framework for a sustainable future. I recommend it highly. The climate crisis is a challenge unprecedented in its scale and complexity. We simply must confront this existential challenge and stop making it worse. That will require the awakening and activism of people all around the world.’

‘The issues explored in The Burning Question are hugely important. Policymakers and the public urgently need to be engaging in this kind of big-picture conversation.’

‘This is a book that needed to be written: it asks the right question then seeks the most effective ways of answering it. An essential contribution to our thinking about climate change.’

‘Fossil fuels are so last century. The Burning Question tells us clearly why and how to get off them, but crucially also explores why we aren’t doing anything much about it at the moment, and points the finger at the villains of the piece. Terrific.’

‘The Burning Question is one of those books that doesn’t shy away from delivering an uncomfortable message – there’s no sweetening of the pill, placating political interests or pandering to commercial sensibilities – it simply tells it like it is. But much more than that, in accessible language it develops responses to the challenges we face – not utopian social change, or unrealistic technical wizardry, but rather a portfolio of options thought through at a system level. The Burning Question is an important contribution to understanding both the scale of the climate challenge and how we may yet develop a low-carbon and climate-resilient society.’

‘To keep climate denial from turning into climate despair – that we don’t know how to solve the climate challenge without suppressing civilisation – we need a realistic assessment of the problem and an optimistic set of solutions. This book gives us both, in a short but compelling narrative that may be the difference between a glide to a decent future and a crash of civilisation. Read it, share it, and start preaching its gospel.’

‘An extremely clear-sighted and highly readable account of the factors fanning the flames of climate change with plenty of practical suggestions how to set about extinguishing them.’

‘It’s terrifyingly simple. Burning carbon made our modern industrial world. Now we’ve got to stop burning it. We’ve got to stop drilling for oil and gas, and leave the coal in the ground. We’ve got to prick the carbon bubble, write off half the assets of the world’s biggest industry, and break the infrastructure and mental lock-in that is preventing viable new energy technologies from taking over. This is the big-picture story of why and how that must happen. And why, so far, we are abjectly failing. Brilliant.’

‘At a time when we’re making the climate debate “small”, a series of bite-sized chunks each to be “smuggled” through a resistant policy system, Berners-Lee and Clark remind us that the debate is actually huge in its global scope, its likely impact and, most importantly of all, in terms of the solutions we need to adopt.’

‘An easy-to-read book about a difficult-to-solve problem. Berners-Lee and Clark illustrate why climate change is such a complex issue. But also that it has a solution.’

Co-Director, Grantham Research Institute on Climate Change and the Environment, LSE

‘The image of scientists and academics used to be one of calm, mild-mannered people but today the frustration among many is palpable. This book shows why. The gap between evidence, policy and practice is yawningly wide. This book tries to bridge that gap, offering a reasoned account of the problem and suggesting what we might do about it – from global policy to culture change.’

‘Climate change is the most difficult problem the world has ever faced. Berners-Lee and Clark have compressed this complex issue into a short and highly readable book that covers science, psychology and sociology. Uncompromisingly rigorous but easy to read, this book is a perfect introduction to the central topic of the twenty-first century.’

‘This book hits the climate nail bang on the head: we can only avoid devastating damage if most of the world’s coal, oil and gas are left in the ground. In wonderfully clear and readable prose, the authors set out the facts and what we must do about them. It deserves to be widely read: I only hope it will reawaken the climate movement, which has gone into such desperate decline over the last three years. Only public pressure will force governments to close down coal fired power stations and end our oil dependence: this book is a lucid and powerful call to arms.’

Visiting professor, Grantham Research Institute, LSE and former special adviser on climate change to the UK Prime Minister

Mike Berners-Lee is a leading expert on carbon emissions, founder of Small World Consulting and author of How Bad Are Bananas? The Carbon Footprint of Everything. He is involved in sustainability research across many departments at Lancaster University and has worked on energy and emissions with a wide range of corporate and public sector organisations.

Duncan Clark is a consultant editor on the Guardian environment desk, co-founder of digital journalism company Kiln and a visiting researcher at the UCL Energy Institute. He helped set up and run the 10:10 climate campaign, is the author of The Rough Guide to Green Living and has edited many books on climate change and related topics.

THE BURNING QUESTION

Typeset in Minion, Sun and Landry Gothic to a design by Duncan Clark and Henry Iles.

All rights reserved. Without limiting the rights under copyright reserved above, no part of this publication may be reproduced, stored or introduced into a retrieval system, or transmitted, in any form or by any means (electronic, mechanical, photocopying, recording or otherwise), without the prior written permission of both the copyright owner and the publisher of this book.

How fossil fuel use and emissions have been rising exponentially for hundreds of years. Why a safe future is incompatible with burning the world’s remaining oil, coal and gas reserves. And how the political process is failing.

How efforts to reduce fossil fuel use often get cancelled out at the global system level. Why we therefore need to deal with the oil, coal and gas head on.

The social, economic and political barriers to cutting fossil fuel use, from the financial value of the reserves and infrastructure to the psychology that stops us engaging with climate change.

The other ways we’re warming the planet, such as soot from cooking fires and methane from livestock. How efforts to reduce these other drivers of climate change will be crucial to what happens in the next few decades.

Do the maths

If the pictures of towering wildfires, devastating droughts and crippling hurricanes haven’t convinced you, here are some hard numbers about climate change. May 2012 was the hottest month on record for the Northern Hemisphere – the 327th consecutive month in which the temperature of the entire globe exceeded the twentieth-century average, the odds of which occurring by simple chance were 3.7 × 10⁹⁹, a number considerably larger than the number of stars in the universe.

The June that followed broke or tied 3,215 high-temperature records across the United States, hot on the heels of America’s warmest ever spring, which crushed the old record by so much that it represented the ‘largest temperature departure from average of any season on record’. The same week, Saudi authorities reported that it had rained in Mecca despite a temperature of 109 degrees, the hottest downpour in the planet’s history. In the autumn, a hurricane of unprecedented power slammed into the New York City region, causing tens of billions of dollars in damage. As the year ended, England announced it had suffered its wettest year ever recorded and Australia entered a hot spell that became so severe its weather service had to add two extra colours to its temperature maps.

Not that our leaders seem to notice. The meeting in Rio for the twentieth-anniversary reprise of a massive 1992 environmental summit accomplished nothing. Unlike George H. W. Bush, who flew in for the first conclave, Barack Obama didn’t even attend. It was ‘a ghost of the glad, confident meeting twenty years ago,’ journalist George Monbiot wrote; no one paid it much attention, footsteps echoing through the halls ‘once thronged by multitudes.’ Since I wrote one of the first books for a general audience about global warming way back in 1989, and since I’ve spent the intervening decades working ineffectively to slow that warming, I can say with some confidence that we’re losing the fight, badly and quickly – losing it because, most of all, we remain in denial about the peril that human civilisation is in.

When we think about global warming at all, the arguments tend to be ideological, theological and economic. But to grasp the seriousness of our predicament, you just need to do a little maths. Recently, an easy and powerful bit of arithmetical analysis first published by financial analysts in the UK has been making the rounds of environmental conferences and journals, but it hasn’t yet broken through to the larger public. This analysis upends most of the conventional political thinking about climate change. And it allows us to understand our precarious – our almost-but-not-quite-finally hopeless – position with three simple numbers.

The first number: 2° Celsius

If the movie had ended in Hollywood fashion, the Copenhagen climate conference in 2009 would have marked the culmination of the global fight to slow changing climate. The world’s nations had gathered in the December gloom of the Danish capital for what a leading climate economist, Sir Nicholas Stern, called the ‘most important gathering since the Second World War, given what is at stake.’ As Danish energy minister Connie Hedegaard, who presided over the conference, declared at the time: ‘This is our chance. If we miss it, it could take years before we get a new and better one. If ever.’

In the event, of course, we missed it. Copenhagen failed spectacularly. Neither China nor the United States, which between them are responsible for 40 per cent of global carbon emissions, was prepared to offer dramatic concessions, and so the conference drifted aimlessly for two weeks until world leaders jetted in for the final day. Amid considerable chaos, President Obama took the lead in drafting a face-saving ‘Copenhagen Accord’ that fooled very few. Its purely voluntary agreements committed no one to anything, and even if countries signalled their intentions to cut carbon emissions, there was no enforcement mechanism.

The accord did contain one important number, however. In Paragraph 1, it formally recognised ‘the scientific view that the increase in global temperature should be below two degrees Celsius’. And in the very next paragraph, it declared that ‘we agree that deep cuts in global emissions are required … so as to hold the increase in global temperature below two degrees Celsius.’ By insisting on two degrees – about 3.6 degrees Fahrenheit – the accord ratified positions taken earlier in 2009 by the G8, and the so-called Major Economies Forum. It was as conventional as conventional wisdom gets. The number first gained prominence, in fact, at a 1995 climate conference chaired by Angela Merkel, then the German minister of the environment and now the centre-right chancellor of the nation.

Some context: so far, we’ve raised the average temperature of the planet just under 0.8 degrees Celsius, and that has caused far more damage than most scientists expected. (A third of summer sea ice in the Arctic is gone, the oceans are thirty per cent more acidic, and since warm air holds more water vapour than cold, the atmosphere over the oceans is a shocking five per cent wetter, loading the dice for devastating floods.) Given those impacts, in fact, many scientists have come to think that two degrees is far too lenient a target. ‘Any number much above one degree involves a gamble,’ writes Kerry Emanuel of MIT, a leading authority on hurricanes, ‘and the odds become less and less favourable as the temperature goes up.’ Thomas Lovejoy, once the World Bank’s chief biodiversity adviser, puts it like this: ‘If we’re seeing what we’re seeing today at 0.8 degrees Celsius, two degrees is simply too much.’

Despite such well-founded misgivings, political realism bested scientific data, and the world settled on the two-degree target – indeed, it’s fair to say that it’s the only thing about climate change the world has settled on. All told, 167 countries responsible for more than 87 per cent of the world’s carbon emissions have signed on to the Copenhagen Accord, endorsing the two-degree target. Only a few dozen countries have rejected it, including Kuwait, Nicaragua and Venezuela. Even the United Arab Emirates, which makes most of its money exporting oil and gas, signed on. The official position of planet Earth at the moment is that we can’t raise the temperature more than two degrees Celsius – it’s become the bottomest of bottom lines. Two degrees.

The second number: 565 gigatonnes

Scientists estimate that humans can pour roughly 565 more gigatonnes of carbon dioxide into the atmosphere by midcentury and still have some reasonable hope of staying below two degrees. (‘Reasonable,’ in this case, means four chances in five, or somewhat worse odds than playing Russian roulette with a six-shooter.) This number isn’t exact, but few dispute that it’s generally right. It was derived from one of the most sophisticated computer-simulation models that have been built by climate scientists around the world over the past few decades. And the number is being further confirmed by the latest climate-simulation models in advance of the next report by the Intergovernmental Panel on Climate Change (IPCC). ‘Looking at them as they come in, they hardly differ at all,’ says Tom Wigley, an Australian climatologist at the National Center for Atmospheric Research. ‘There’s maybe forty models in the data set now, compared with twenty before. But so far the numbers are pretty much the same. We’re just fine-tuning things. I don’t think much has changed over the last decade.’ William Collins, a senior climate scientist at the Lawrence Berkeley National Laboratory, agrees. ‘I think the results of this round of simulations will be quite similar,’ he says. ‘We’re not getting any free lunch from additional understanding of the climate system.’

We’re not getting any free lunch from the world’s economies, either. With only a single year’s lull in 2009 at the height of the financial crisis, we’ve continued to pour record amounts of carbon into the atmosphere, year after year. The International Energy Agency’s (IEA) latest figures showed that carbon dioxide emissions rose to 31.6 gigatonnes in 2011, up 3.2 per cent from the year before. America had a warm winter and converted more coal-fired power plants to natural gas, so its emissions fell slightly; China kept booming, so its carbon output (which recently surpassed the US) rose 9.3 per cent; the Japanese shut down their fleet of nukes post-Fukushima, so their emissions edged up 2.4 per cent. ‘There have been efforts to use more renewable energy and improve energy efficiency,’ said Corinne Le Quéré, who runs England’s Tyndall Centre for Climate Change Research. ‘But what this shows is that so far the effects have been marginal.’ In fact, study after study predicts that carbon emissions will keep growing by roughly 3 per cent a year – and at that rate, we’ll blow through our 565-gigatonne allowance in sixteen years, around the time today’s preschoolers will be graduating from high school. ‘The new data provide further evidence that the door to a two-degree trajectory is about to close,’ said Fatih Birol, the IEA’S chief economist. In fact, he continued, ‘When I look at this data, the trend is perfectly in line with a temperature increase of about six degrees.’ That’s almost 11 degrees Fahrenheit, which would create a planet straight out of science fiction.

So, new data in hand, everyone at the Rio conference renewed their ritual calls for serious international action to move us back to a two-degree trajectory. The charade continued in November when the latest Conference of the Parties (COP) of the UN Framework Convention on Climate Change convened in Qatar. That was COP 18. COP 1 was held in Berlin in 1995, and since then the process has accomplished essentially nothing. Even scientists, who are notoriously reluctant to speak out, are slowly overcoming their natural preference to simply provide data. ‘The message has been consistent for close to thirty years now,’ Collins says with a wry laugh, ‘and we have the instrumentation and the computer power required to present the evidence in detail. If we choose to continue on our present course of action, it should be done with a full evaluation of the evidence the scientific community has presented.’ He pauses, suddenly conscious of being on the record. ‘I should say, a fuller evaluation of the evidence.’

So far, though, such calls have had little effect. We’re in the same position we’ve been in for a quarter-century: scientific warning followed by political inaction. Among scientists speaking off the record, disgusted candour is the rule. One senior scientist told me, ‘You know those new cigarette packs, where governments make them put a picture of someone with a hole in their throats? Gas pumps should have something like that.’

The third number: 2,795 gigatonnes

This number is the scariest of all – one that, for the first time, meshes the political and scientific dimensions of our dilemma. It was brought to wide attention first by the Carbon Tracker Initiative, a team of London financial analysts and environmentalists who published a report in an effort to educate investors about the possible risks that climate change poses to their stock portfolios. The number describes the amount of carbon already contained in the proven coal and oil and gas reserves of the fossil-fuel companies, and the countries (think Venezuela or Kuwait) that act like fossil-fuel companies. In short, it’s the fossil fuel we’re currently planning to burn. And the key point is that this new number – 2,795 – is higher than 565. Five times higher.

The Carbon Tracker Initiative combed through proprietary databases to figure out how much oil, gas and coal the world’s major energy companies hold in reserve. The numbers aren’t perfect – they don’t fully reflect the recent surge in unconventional energy sources like shale gas, and they don’t accurately reflect coal reserves, which are subject to less stringent reporting requirements than oil and gas. But for the biggest companies, the figures are quite exact: If you burned everything in the inventories of Russia’s Lukoil and America’s ExxonMobil, for instance, which lead the list of oil and gas companies, each would release more than 40 gigatonnes of carbon dioxide into the atmosphere.

Which is exactly why this new number, 2,795 gigatonnes, is such a big deal. Think of two degrees Celsius as the legal drinking limit – equivalent to the 0.08 blood-alcohol level below which you might get away with driving home. The 565 gigatonnes is how many drinks you could have and still stay below that limit – the six beers, say, you might consume in an evening. And the 2,795 gigatonnes? That’s the three 12-packs the fossil-fuel industry has on the table, already opened and ready to pour.

We have five times as much oil and coal and gas on the books as climate scientists think is safe to burn. We’d have to keep 80 per cent of those reserves locked away underground to avoid that fate. Before we knew those numbers, our fate had been likely. Now, barring some massive intervention, it seems certain.

Yes, this coal and gas and oil is still technically in the soil. But it’s already economically aboveground – it’s figured into share prices, companies are borrowing money against it, nations are basing their budgets on the presumed returns from their patrimony. It explains why the big fossil-fuel companies have fought so hard to prevent the regulation of carbon dioxide – those reserves are their primary asset, the holding that gives their companies their value. It’s why they’ve worked so hard these past years to figure out how to unlock the oil in Canada’s tar sands, or how to drill miles beneath the sea, or how to frack the Appalachians.

If you told Exxon or Lukoil that, in order to avoid wrecking the climate, they couldn’t pump out their reserves, the value of their companies would plummet. John Fullerton, a former managing director at JP Morgan who now runs the Capital Institute, calculates that at today’s market value, those 2,795 gigatonnes of carbon emissions are worth about $27 trillion. Which is to say, if you paid attention to the scientists and kept 80 per cent of it underground, you’d be writing off $20 trillion in assets. The numbers aren’t exact, of course, but that carbon bubble makes the housing bubble look small by comparison. It won’t necessarily burst – we might well burn all that carbon, in which case investors will do fine. But if we do, the planet will crater. You can have a healthy fossil-fuel balance sheet, or a relatively healthy planet – but now that we know the numbers, it looks like you can’t have both. Do the maths: 2,795 is five times 565. That’s how the story ends.

A longer version of this piece originally appeared in Rolling Stone magazine.¹

Introduction

The aim of this book is to give a very big perspective on a very big challenge. Much of it revolves around two key messages that are widely ignored. The first of these is that avoiding unacceptable risks of catastrophic climate change means burning less than half of the oil, coal and gas in currently commercial reserves – and a much smaller fraction of all the fossil fuels under the ground. This isn’t a new realization. NASA scientist James Hansen and colleagues first pointed it out many years ago and as we were writing this book environmentalist Bill McKibben blasted the idea to a wider audience in the article excerpted above, the original of which became an unexpected viral hit for the Rolling Stone website. Our book picks up where McKibben signs off, exploring the implications of the world’s fossil fuel abundance. Who owns it all? What’s it worth? Is it really true that we can only burn a fifth, or that stock exchanges are exposed to a ‘carbon bubble’? Could we not burn the fuel and capture the carbon? How does all this affect the geopolitics of the issue?

This book’s second big message is that viewed at the global level – the system level – many of the things we assume will help reduce fossil fuel use turn out to make much less of a difference than common sense would suggest. While clean energy, greener behaviour, energy efficiency and slowing population growth all have a key role to play, they don’t appear to reduce the ever-increasing rate at which fossil fuels come out of the ground. A close look at the statistics shows that man-made carbon emissions have followed a long-term exponential trend that has proved uncannily resilient to social or technical change. There are powerful feedback mechanisms at work in human energy use capable of cancelling out apparent green progress. It’s like squeezing a balloon: gains made in one place reappear as bulges elsewhere.

When you put these two messages together, and look at them in the light of the latest climate science, the inescapable finding is that we need to deal with the fossil fuel problem head on. In other words, there’s no safe alternative to deliberately and rapidly constraining the rate at which fossil fuels come out of the ground and flow through the global economy. One day technology and infrastructure may exist to allow us to burn the world’s oil, coal and gas safely by capturing and burying the carbon emissions. That technology needs much more effort put into it, but on current trends remains a long way off. In the meantime, the choice we face is between taking unimaginable risks with the planet and leaving vastly valuable fossil fuels in the ground.

Given that stark choice, and our inability to dent the emissions trajectory so far, it seems critical that we get a proper understanding of the core barriers that are holding us back. In the chapters following, we explore the economic, psychological, cultural and political roots of our inertia. We also show how the money bound up in oil, coal and gas reserves has blocked political progress and clouded the analysis. The fossil fuel sector is often described as the biggest and most profitable industry of all time, and it’s currently working hard not just to resist carbon cuts but to grow its reserves and markets as fast as possible. The world needs to send it – and its investors – a loud and clear message: stop!

But it’s not good enough to pin all the blame on fossil fuel companies as there are many other barriers to progress. We look at the rate at which the world is sinking money into vehicles, power plants and other infrastructure that require fossil fuels to run; the nervousness of policymakers to do anything that will push up energy prices; and perhaps most importantly of all, the host of social and psychological traits that have been stopping our species from waking up to the threat we face.

While fossil fuel is the key driver of climate change, humans also tamper with the atmosphere by releasing a host of other greenhouse gases and particles, many of which come from agriculture and deforestation. We look at how rapid action here can increase the chance of successfully tackling climate change and buy us some time to get fossil fuels under control. The way the world’s land is managed over the coming decades will be crucial not just for feeding the growing population, but for cutting emissions, capturing carbon, protecting biodiversity and even, if humanity plays its cards right, responsibly liberating some land for producing energy.

Finally, we outline what we think needs to be done. We argue that tackling the problem will require a mix of harder global politics, passionate campaigning and smarter use of technology – each of which needs to support the others. We address the critical challenge of collectively waking up from decades of slumber. And we look at leadership, too often absent thus far, describing how everyone can contribute.

Some of the facts about climate change are uncomfortable but this book is about clarity so we have deliberately avoided playing down the severity of the situation just to keep the message palatable for our readers. But nor have we feigned optimism, so when you do see glints of positivity, they too are real.

A note about notes

Climate change is surely the most multi-layered and intriguing problem in history – a perfect storm of money and power, science and politics, technology and the human mind. In order to address and join the dots between these many elements, we have focused unapologetically on the big picture: the core perspectives that too often get lost amid detailed discussion. If you want chapter and verse on the economics, politics or psychology of climate change, or on alternative energy sources, then you’ll need to look elsewhere. A good starting point would be our endnotes, which are designed to be read and often include further discussion as well as links to sources and suggested reading. In addition to appearing at the back of the book, they are posted online, along with some of the key datasets that we’ve used, at burningquestion.info – where readers can also get in touch with us to share reactions and ideas.

PART ONE
A problem of abundance

1. The curve

Fossil fuel use and emissions have been rising exponentially for more than a century

Nothing has shaped human history more than our use of energy. It was energy from the sun that provided the conditions for life on earth. It was the competition for food energy that determined the winners and losers of evolution. It was energy from fire that enabled early humans to cook, radically improving their diets and enabling their energy-hungry brains to grow even bigger.¹ Bigger brains eventually led to agriculture – a systematic means of harnessing the sun’s energy – which in turn freed us from the constraints of nomadic existence and gave rise to permanent settlements.

In villages and towns, the human population flourished – as did knowledge. More people with more ideas unlocked yet more sources of energy. Domesticated animals pulled ploughs and dug irrigation channels, enabling us to exploit more land. Forests – essentially banks of stored solar energy – were cleared first to produce firewood and building materials, then to make charcoal, a higher-grade form of energy that burned hot enough to smelt the bronze for the bronze age and the iron for the iron age. Better materials led to better tools and technology, which soon unlocked yet more types of energy. Mills started harnessing the kinetic energy of rivers to grind grain, operate mechanical hammers and even make cloth. Wind energy was harvested too, not just by mills but also by sailing ships, opening up long-distance trading, both in goods and knowledge – including knowledge about energy.

More energy, more technology, more people, more energy – this age-old feedback loop was the motor that enabled humankind to dominate the earth. From the earliest days, it brought environmental side effects. As our numbers ballooned we hunted many species to extinction. As we dammed rivers for watermills we killed off migratory fish. But for most of human history, the earth coped reasonably well with the onslaught its brainiest and most energy-hungry inhabitant was wreaking. That started to change in the eighteenth century when people accessed significant quantities of fossil fuels. While burning wood had allowed us to release solar energy captured over years, decades or centuries, fossil fuels contained hundreds of millions of years’ worth of sunlight. The energy was stored in carbon-based molecules formed when ancient plants decomposed anaerobically under layers of sediment to form incredibly energy-dense solids, liquids and gases: coal, crude oil and natural gas.

Small-scale fossil fuel use began much earlier. Coal was burned in ancient Greece, Roman Britain, Aztec Mexico and imperial China – though it remained a novelty to Marco Polo who wrote with amazement during a thirteenth-century trip to China about ‘a kind of black stones existing in beds in the mountains, which … burn like firewood.’² The reason fossil fuels remained so obscure for so long was that most of them were trapped deep underground. Finding them was difficult and getting them out was even harder.

The steam engine solved that problem. It used the incredible power of coal to drain water from deep mines, making it possible to access more coal to power more steam engines. First in Britain, then in Europe, Japan and elsewhere, the energy–society feedback loop went into overdrive. Coal enabled railways, steam ships, blast furnaces, brick kilns and metal smelters to multiply. It increased the supply of every commodity and material and boosted progress on every front of technology, from medicine to microscopy. As political economist William Stanley Jevons noted in 1865, energy from coal had become ‘the universal aid … the factor in everything we do’.³ And that was before coal had enabled electricity to develop from a scientific curiosity into a major new industry, offering countless new ways to consume energy.

Importantly, coal didn’t replace existing energy sources; it augmented them. Global consumption of energy from trees and other forms of ‘biomass’ hardly changed as industrial-scale coal mining spread around the world. In turn, use of coal kept growing as its liquid cousin – crude oil – rose to significance in the early twentieth century. With oil came motorised transport, which amplified energy use yet further. It allowed us to move around faster, trade with people further afield, and to spread into suburbs. Homes grew in both numbers and size, increasing demand for building materials, furniture, heating and electricity – all of which took yet more energy to provide. Food production was also transformed by oil, which powered tractors, trucks and factory fishing fleets as well as easing pressure on farmland by providing synthetic alternatives to cotton, wool and wood. With less need for manual labourers, the workforce shifted towards factories, many of which not only consumed energy directly but churned out machines such as cars, light bulbs and radios that themselves took energy to run.

Global use of oil and coal kept rising as the third major fossil fuel – natural gas – started to scale up after the Second World War. Gas boosted energy supply directly, ramping up electricity production and fuelling boilers and cookers. But it also drove up demand for every other kind of energy by enabling the continued expansion of the global population. As human numbers rose towards three billion in the 1950s, a catastrophic crunch in food production was avoided in large part thanks to huge quantities of nitrogen fertilisers produced from natural gas. As the population shot up, so did energy demand.

More energy, more technology, more people, more energy. The feedback loop kept whirring throughout the twentieth century as holiday flights, cars, washing machines and central heating became the norm in wealthy countries. Energy supply expanded too as large-scale hydroelectric and nuclear power plants started coming on stream in significant numbers. But human demand for energy showed no signs of hitting a ceiling so fossil fuel use kept rising too. Society produced more goods of every type and found new ways to use energy – from domestic air conditioning and space missions to kidney dialysis machines and, of course, computers, which turned out to be extremely helpful for finding yet more fossil fuel reserves and developing the tools for getting them out of the ground.

The effects of escalating energy use on the planet have been extraordinary. Today we total more than seven billion people and consume more than five-hundred billion billion joules of energy each year. That’s comparable to each man, woman and child having more than a hundred full-time servants doing manual work on their behalf.⁴ Aided by this vast army of energy slaves, we’ve transformed the planet so fundamentally that scientists are currently considering whether formally to call time on the Holocene geological era and recognise that we’re now in the Anthropocene: the human era. A remarkable 40 per cent of the world’s land surface is now farmed or grazed. Most of the large rivers are dammed to provide water for irrigation, washing and drinking. Seen from space, even the shadowy side of the planet glows visibly thanks to tens of billions of electric lights.

But perhaps the greatest adjustment that human energy use has made to the Earth remains invisible. Our fuels and farming have been reformulating the atmosphere by flooding the air with carbon that was once locked up in forests, coal, oil and gas. Nineteenth-century physicists theorised that all this extra carbon – in the form of carbon dioxide gas – would warm the planet by trapping heat that would otherwise escape to space. The science firmed up over the decades, though no one knew if the impacts would be positive or negative and few were sufficiently concerned to consider abandoning the fossil fuels that had taken humankind to such heights. So the energy–society feedback kept spinning and emissions of carbon dioxide kept climbing.

But to say that carbon emissions have been climbing for centuries doesn’t tell the whole story. They have in fact been climbing in a very specific way: exponentially.

The carbon curve

An exponential curve has special properties. At any point, the steepness is proportional to the height. Not only that but the rate of increase is proportional to the steepness.⁵ In other words, it’s the type of curve you get when the more of something you have, the faster that something grows. Exponentials often turn up when there’s a positive feedback loop at work. The population of insects in a jar follows an exponential curve for as long as there is adequate food supply because the more insects there are the faster they can breed. A credit card debt grows exponentially as the interest gets applied to ever more interest.

Exponential curves can’t go on forever. They get steeper and steeper until eventually, something has to give. Sometimes they crash, like the population of the insects in the jar when the food runs out, or the credit card debt when bankruptcy is declared. Or sometimes they tame themselves more gently – such as the way global population has slowed to a steady rise over the past few decades (more on that later). But they can’t go on for all time.

Although there is a bit of snaking around along the way, the long-term fit of global carbon emissions to an exponential curve is uncanny – as the graph overleaf shows. The most noticeable deviation is the slow-down in emissions growth in the first half of the twentieth century. It’s an open question whether this was the result of two world wars, or the Great Depression, or global energy supplies struggling to keep up with demand. But the carbon curve quickly got back on track in the 1950s, helped along by many huge oilfields coming on stream and a major acceleration in global population. Emissions then surged above the long-term trend in the energy-profligate 1960s before slowing in the wake of oil price spikes in the 1970s and early 1990s and finally getting back on track around the turn of the millennium.

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Annual man-made emissions of carbon dioxide from all major sources – fossil fuel use, cement production, deforestation and land use changes – plotted against an exponential line. The neatness of the correlation was first explored in a study by Andrew Jarvis and colleagues at Lancaster University.⁶

It’s tempting to assume that the last decade must surely have seen a bit of slowdown on the global carbon curve given all the green summits, hybrid cars and the low-energy light bulbs. Focusing on just a few years isn’t statistically very meaningful, but for what it’s worth the last decade tells the opposite story, lying above rather than below the long-term trend line. From 2000 to 2010, the average annual growth of carbon emissions from all man-made sources was around 2.3 per cent – higher than the very long-term trend of 1.8 per cent. The figures would look even worse was it not for savings in deforestation; fossil fuel emissions rose by a massive 3 per cent a year for the last decade and continued to do so in 2011, the last year for which reliable data is available at the time of writing.⁷ As we go to press, it looks like 2012 saw a similar rise.

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A close up of the same graph since 2000. In this period average emissions growth has been around 2.3 per cent – higher than the very long-term trend of 1.8 per cent. (Includes some estimates for deforestation and cement.)

The unremittingly exponential nature of the global carbon curve fits perfectly with the idea that society’s use of energy is driven by a powerful positive feedback mechanism. It also makes it painfully clear that none of the action taken so far to deal with climate change has succeeded in making the smallest difference at the global level. It is theoretically possible that without all the efficiency gains and corporate responsibility reports, the community action groups, global summits and so on, emissions might have been even higher: we might have deviated significantly above the long-term trend. That would require a coincidence but is not impossible. It is also conceivable that all those efforts have been successfully laying the groundwork for reduced global emissions in the future. But the striking reality is that any progress so far is invisible on the graph.

Interestingly, the simple and predictable global emissions trend belies a shifting picture in the sources of those emissions. The destruction of forests which dominated the human carbon footprint 160 years ago has been increasingly dwarfed first by coal and then by a combination of coal, oil and gas. And, in a rare good news story, emissions from deforestation have fallen sharply in absolute terms during the last two decades. But the curve has carried on as if nothing had changed. Similarly, at first glance the energy feedback loop appears to have finally burned out in rich countries, where energy use and emissions (and in some cases populations) are now falling. But again the global exponential trend has been unaffected. It looks as if the carbon curve exhibits a capacity for self-regulation, similar to the way a human body maintains a steady temperature almost regardless of what goes on in its surrounding environment. We’ll explore this more in part two.

The unflinching resilience of the curve, decade after decade, bouncing back from wars and depressions, and despite endless technological revolutions, tells us a lot about the challenge we are up against. Not only are we faced with trying to slow down the proverbial oil tanker; we need to do so while it’s accelerating harder than ever before, driven by what appears to be a deep dynamic in which access to energy begets yet more energy.

But as we’ve seen, exponentials can’t go on for all time, and our carbon curve is no exception, as a few back-of-the-envelope calculations reveal. If we stayed on our current trajectory for, say, 600 years, emissions would rise so steeply that our fuel-burning would consume all the oxygen that is currently in the Earth’s atmosphere every single year, leaving nothing at all for us to breath.⁸ So we can safely say that we’ll be coming off the curve well before 2600 AD, whether we like it or not. In reality, supplies of fossil fuels would run out much sooner than that. Chapter three takes stock of all the oil, coal and gas resources left in the world. The total suggests that if the current carbon curve continued, we’d most likely run out of all of them – including all the obscure and unconventional fuel sources such as tar sands and shale gas – within a century or so.

In other words, the carbon curve doesn’t necessarily have that much life left in it. Although it’s been running for hundreds of years, it most likely couldn’t run for hundreds more – even if we didn’t care about climate change. So our first really big question is, can we just let the curve run its ‘natural’ course and either crash or level off of its own accord as fossil fuels get more scarce and expensive and other energy sources take over? Or do we need to intervene to bring it to heel more quickly? The answer depends mainly on two other questions. How quickly will we run into trouble if we let things run their course? And how does that fit in with the amount of fossil fuels we have left?

2. Heading for trouble fast

Before exploring why the curve keeps outsmarting us – and what it will take to tame it – we’ll pause to check whether carbon emissions are really such a big deal. Does global warming really represent a significant threat to humankind? If so, what kind of threat? What will happen if we don’t find a way to reduce emissions? Would a bit more warming necessarily be such a bad thing?

We’ll take it as read that man-made emissions of carbon dioxide and other greenhouse gases cause global warming. Many people resist this idea, partly for psychological and political reasons that we’ll explore later, but for now that doesn’t warrant a diversion. Anyone who is in doubt should take note that every science academy in the world – without exception – agrees that the planet has been rapidly getting hotter and that emissions from human activity are almost certainly the main cause.¹

Here, extremely briefly, are the core facts. Basic physics, known way back in the nineteenth century, tells us that additional greenhouse gases in the air will warm the planet; we’ve been releasing those gases and they’ve been measurably accumulating in the air; the Earth is responding just as the physics would predict; and there’s no other plausible explanation for that warming.

Lest there be any doubt that the world is getting hotter, as we write this, January 2013 has just been announced by the US government’s National Climate Data Center as the 335th consecutive month to have been warmer at the global level than the twentieth-century average for that month.² The last time a month fell below the century average was February 1985, around the time when Ronald Regan begun his second term in office and Mikhail Gorbachev became General Secretary of the Soviet Communist Party. Some people argue that the temperature records must be faulty, but there’s a huge wealth of corroborating evidence, such as melting glaciers and sea ice, shifting growing seasons and wildlife, rising sea levels and greater humidity.³

THE BURNING QUESTION

Contents

Do the maths

The first number: 2° Celsius

The second number: 565 gigatonnes

The third number: 2,795 gigatonnes

Introduction

A note about notes

PART ONEA problem of abundance

1. The curve

The carbon curve

2. Heading for trouble fast

PART ONE
A problem of abundance