A slight clinking behind me made me turn my head. Six black men advanced in a file, toiling up the path. They walked erect and slow, balancing small baskets full of earth on their heads, and the clink kept time with their footsteps. […] I could see every rib, the joints of their limbs were like knots in a rope; each had an iron collar on his neck, and all were connected together with a chain whose bights swung between them, rhythmically clinking.

This scene, from Joseph Conrad’s Heart of Darkness, is set in the heyday of European colonialism, a little more than a hundred years ago.

The pitiless brutality with which early industrial countries satisfied their hunger for raw materials, land and power, and which left its mark on whole continents, cannot be seen in the landscape of the West today. The memory of exploitation, slavery and extermination has succumbed to democratic amnesia, as if the countries of the West had always been as they now are and their superior wealth and power were not built upon a murderous history.

Instead, the West prides itself on its inventiveness, its observance and defence of human rights, its political correctness and humanitarian stance when a civil war, flooding or drought threatens human life in some part of Africa or Asia. Governments order military intervention to spread democracy, overlooking that most Western democracies rest on a history of exclusion, ethnic cleansing and genocide. Whereas the asymmetrical history of the nineteenth and twentieth centuries has translated into luxurious living standards in Western societies, its violence still weighs heavily on many parts of the second and third worlds. Quite a few post-colonial countries have never made it to real statehood, let alone achieved prosperity; many have continued to experience the old exploitation under different conditions, and the signs often point towards further decline rather than significant improvement.

Climate change resulting from the insatiable hunger for fossil fuels in the early industrial countries hits the poorest regions of the world hardest – a bitter irony that flies in the face of any expectation that life is fair. Figure 1.1 shows the remnants of the Eduard Bohlen steamer, which were dug up after almost a hundred years from the sands of the Namibian desert. It played a minor role in the history of major injustice. On 5 September 1909, it ran aground in thick fog off the coast of the country that was then called German South-West Africa. Today the wreck lies 200 metres inland, the desert having gradually inched its way out to sea in the intervening period. Since 1891 the Eduard Bohlen had made regular stops in South-West Africa, carrying mail for the Woermann Lines based in Hamburg. But during the German colonial war against the Herero people, it was converted into a slave ship.

In this genocidal war, the first of the twentieth century, a large part of the native population of South-West Africa lost their lives, while concentration camps were built to house prisoners of war sold off as slave labourers. Right at the beginning of the war, the German colonial authorities offered Hewitt, a South African dealer, 282 captured prisoners, whom they had placed on board the Eduard Bohlen, not knowing what else to do with them until the Hereros were defeated. Hewitt jumped at the opportunity and managed to drive the price down to 20 marks per head, arguing pertinently that, since the men were already out at sea, he should not have to pay the normal price and customs duties for finished goods. So, on 20 January 1904 the Eduard Bohlen left Swakopmund bound for Cape Town, where the men were put to work in the mines.¹

The Herero opened their campaign against colonial rule on the night of 11–12 January 1904, destroying a railway track and several telegraph lines and killing 123 German men in raids on farms.² After talks to suspend hostilities led nowhere, the imperial government in Berlin sent out an expeditionary force under the command of Lieutenant-General Lothar von Trotha, who immediately declared a war of extermination. His aim was not only to defeat the Herero militarily but to force them to fight in the wastes of the Omaheke desert, where he controlled the watering places and could simply watch them die of thirst.³ This gruesome strategy was so successful that the Herero were reported to be cutting their animals’ throats and drinking their blood, then squeezing the last drop of moisture out of the stomach contents. But they died all the same.⁴

The war continued after the Herero fighters were wiped out. The Nama, another native people, were to be disarmed and subjugated once German troops had established a presence in their area. The Nama, unlike the Herero, did not opt for pitched battles but resorted to guerrilla warfare, which presented the colonial army with considerable problems and impelled it to adopt measures that would find frequent application as the bloody century progressed. In order to rob the Nama guerrillas of support, the Germans murdered their women and children or herded them into concentration camps.

Violence occurs when there is pressure to take action that will produce results. If these are not forthcoming, new forms of violence are devised – and, if found to be effective, are repeatedly applied. Violence is innovative: it develops new forms and new conditions. Nevertheless, it took the German colonial army more than three years to crush the Nama people. The concentration camps, by the way, were not all under state control; private companies such as Woermann also ran a line in forced labour.⁵

This war was not only an example of the ruthlessness of colonial power but also a blueprint for future genocides; its strategic intent was total extermination, by working prisoners to death in concentration camps. At the time all this could be written of as a success story. The History Department of the General Staff proudly reported in 1907 that ‘no trouble, no deprivation was spared to rob the enemy of the last remnants of his capacity to resist. He was driven from water-hole to water-hole like a beast hounded half to death, until, having lost all will, he fell victim to natural forces in his own country. The waterless Omaheke would complete the task begun by German force, the annihilation of the Herero people.’⁶ That was a hundred years ago. The forms of violence have changed since then, and even more the ways of speaking about them. The West now uses force directly against other countries only in exceptional cases; today’s wars involve long chains of agency, in which violence is delegated, reshaped and invisible. The conflicts of the twenty-first century are post-heroic, seemingly waged against the will of their actors. And since the Holocaust it has been impossible to speak with pride of exterminating whole peoples.

The Eduard Bohlen rusts away in the desert sands, and perhaps the whole Western social model, with all its democracy, freedoms, liberalism, art and culture, will appear to a historian of the twenty-second century as an equally strange relic from another world. If there are still historians in the twenty-second century …

This social model, so remorselessly successful for a quarter of a millennium, is becoming global and even drawing once-communist (just barely communist) countries into the intoxication of a standard of living complete with cars, flat-screen TVs and travel to faraway lands. But, at this very moment, it is also running up against operational limits that scarcely anyone has allowed for. The emissions caused by the energy-hungry industrial heartlands, and increasingly also by emerging economies, threaten to knock the climate out of kilter. The consequences are beginning to make themselves felt, but it is impossible to predict what lies ahead. The only certainty is that the unrestricted use of fossil fuels cannot continue for ever – not so much because they will eventually run out (which has been assumed for a long time) as because the climatic effects are uncontrollable.

When global warming due to atmospheric pollution rises above 2 degrees, the Western model will reach its limits of controllability. But there is more. An economy based on growth and resource depletion cannot function globally, since it logically implies that power is accumulated in one part of the world and applied in another. It is in essence particularist, not universal: everyone cannot exploit everyone else at the same time. Astronomy has not revealed any other planets within reach that might be colonized, and so the conclusion is inescapable that Earth is and will remain an island. Humans cannot simply pack up and move on when the land has been grazed bare and the mines have been phased out.

As resources start to run out, at least in many parts of Africa, Asia, Eastern Europe, South America, the Arctic and the Pacific islands, more and more people will have fewer and fewer means to ensure their survival. Obviously this will lead to violent conflicts among those who wish to feed off the same area of land or to drink from the same trickling water source, and just as obviously, in a not so distant future, it will no longer be possible to distinguish between war refugees and environmental refugees. New wars will be environmentally driven and cause people to flee from the violence, and, since they will have to settle somewhere, further sources of violence will arise – in the very countries where no one knows what to do with them, or on the borders of countries they want to enter but which have no wish at all to receive them.

This book is concerned with the question of how climate and violence go together. In some cases, such as the war in Sudan, the link is direct and palpable. In many other contexts of present or future violence – civil wars and simmering conflicts, reigns of terror, illegal migration, border disputes, unrest and insurgency – the connection between global warming and environmental conflicts is only indirect; it makes itself felt mainly in the impact of climate change on global inequalities and living conditions, which varies enormously from country to country.

But, whether wars in the twenty-first century are directly or indirectly due to climate change, violence has a great future ahead of it. We shall see not only mass migration but also violent solutions to refugee problems, not only tensions over water or mining rights but also resource wars, not only religious conflicts but also wars of belief. A hallmark of the violence practised by the West is an effort to delegate as much of it as possible to mercenaries or private security companies, or, in the case of border control, to agencies operating in economically and politically dependent countries that are the source of likely immigration. Security policies designed to catch criminals before they commit a crime – to shift the offence ‘upstream’, as it were – are part of this increasing trend towards the indirect use of force. Whereas the West prefers this to the kind of open war it has had to fight in Iraq or Afghanistan, social conditions in other countries are such that violence is a permanent and central factor that people have to face in eking out an existence. All this is an expression of the asymmetry that became decisive for world history two and a half centuries ago and has been deepened by the processes of global warming.

Crystal ball gazing at future wars and conflicts would be an idle pursuit, since social processes do not develop in linear fashion. We cannot know today which migrations will cause the Siberian permafrost to thaw, or which outbreaks of violence will trigger the flooding of a megacity or a whole country. Still less can we know how people will react in future to perceived threats, or what effects their reactions will unleash. The same caveat applies to scientific attempts to understand climate change and its likely consequences. It is all too easy to overlook the fact that the arguments employed by climatologists – for example, when they use precisely datable ice or rock layers to measure carbon dioxide concentrations in the air or water – usually highlight processes of change that can be shown to have occurred in history.

The future scenarios of greatest concern to the public therefore rest upon data from the past. Similarly, this book will not so much speculate on possible futures as analyse how and why violence has been exercised in the past and present, in order to gauge what future lies in store for us in the twenty-first century. Since violence is always an option for human action, it is inevitable that violent solutions will also be found for problems that have their origin in environmental changes.

The following pages will therefore not only offer accounts of climate wars but also investigate how people decide to kill others in war, or how their perception of the environment itself changes. For it is not objective circumstances themselves that determine how people behave, but the manner of their interpretation. It also needs to be asked why there are some wars that no one is interested in ending, and why increasing numbers are willing to trade their freedoms for promises of security.

The book starts by presenting a case that problems push for solutions when they are perceived as threatening. After a three-part investigation of killing – yesterday, today and tomorrow – it describes the ‘shifting baselines’ – that is, the fascinating phenomenon that people change their perceptions and values along with their environment, without even realizing that they are doing it.

The book naturally ends with a consideration of what might be done to prevent the worst from happening, or – put more loftily – to draw some practical lessons from history. Chapter 11, the first concluding chapter, examines the possibilities for cultural change that might permit an escape from the deadly logic of unstoppable growth and limitless consumption, one which does not make people feel that they have to sacrifice something. Optimists should stop reading at the end of this chapter and reflect on how a start might be made with the concept of a good society that is developed in it.

The second concluding chapter, chapter 12, outlines my own view of how things will shape up in the wake of climate change – a rather bleaker view, it must be said. The consequences will not only change the world but establish different social conditions from those we have known until now; they will also spell the end of the Enlightenment and its conception of freedom. But some books one writes in the hope of being proved wrong.