The God Species: How Humans Really Can Save the Planet...

Many will find my analysis and conclusions rather unsettling – not least my colleagues in the Green movement, many of whose current preoccupations are shown to be ecologically wrong. Until now, environmentalism has been mostly about reducing our interference with nature. Central to the standard Green creed is the idea that playing God is dangerous. Hence the reflexive opposition to new technologies from splitting the atom to cloning cattle. My thesis is the reverse: playing God (in the sense of being intelligent designers) at a planetary level is essential if creation is not to be irreparably damaged or even destroyed by humans unwittingly deploying our new-found powers in disastrous ways. At this late stage, false humility is a more urgent danger than hubris. The truth of the Anthropocene is that the Earth is far out of balance, and we must help it regain the stability it needs to function as a self-regulating, highly dynamic and complex system. It cannot do so alone.

This means jettisoning some fairly sacred cows. Nuclear power is, as many Greens are belatedly realising, environmentally almost completely benign. (The Fukushima disaster in Japan did nothing to change this sanguine assessment, and perhaps more than anything reconfirmed it: more on that later.) Properly deployed, nuclear fission is one of the strongest weapons in our armoury against global warming, and by rejecting it in the past campaigners have unwittingly helped release tens of billions of tonnes of carbon dioxide into the atmosphere as planned nuclear plants were replaced by coal from the mid-1970s onwards. Anyone who still marches against nuclear today, as many thousands of people did in Germany following the Fukushima accident, is in my view just as bad for the climate as textbook eco-villains like the big oil companies. (Germany’s over-hasty switch-off of seven of its nuclear power plants after the Japanese tsunami will have led to an additional 8 million tonnes of carbon dioxide in just three months.

(#litres_trial_promo)) The same goes for genetic engineering. The genetic manipulation of plants is a powerful technology that can help humanity limit its environmental impact and feed itself better in the process. I personally campaigned against it in the past, and now realise that this was a well-intentioned but ignorant mistake. The potential of synthetic biology I can only begin to guess at today in early 2011. But the lesson is clear: we cannot afford to foreclose powerful technological options like nuclear, synthetic biology and GE because of Luddite prejudice and ideological inertia.

Indeed, if we apply the metric of the planetary boundaries to the campaigns being run by the big environmental groups, we find that many of them are irrelevant or even counterproductive. Carbon offsetting is a useful short-term palliative that the Green movement has discredited without good reason, harming both the climate and the interests of poor people in the process. Some Green groups have also made it very difficult to use the climate-change negotiations as a way to save the world’s forests by insisting that rainforest protection should not be eligible for carbon credits. In addition, environmental and development NGOs in general have been much too easy on rapidly emerging big carbon emitters like China and India, whose governments need to be pressed or assisted to eschew coal in favour of cleaner alternatives. Blaming the rich countries alone for climate change may tick all the right ideological boxes, but it is far from being the full story.

Most Greens also emphatically object to geoengineering – the idea that we could consciously alter the atmosphere to counteract climate change, for example by spraying sulphates high in the stratosphere to act as a sunscreen. But the objectors seem to forget that we are already carrying out massive geoengineering every day, as a hundred million people step into their cars, a billion farmers dig their ploughs into the soil, and 10 million fishermen cast their nets. The difference seems to come down to one of intent: is unwitting and bad planetary geoengineering really better than witting and good planetary geoengineering? I am not so sure. At the very least a reflexive rejectionist position risks repeating the mistakes of the anti-genetic engineering campaign, where opposing a technology a priori meant that lots of potential benefits were stopped or delayed for no good cause. Being against something can have just as big an opportunity cost as being for it.

Certainly deciding on something as epochal as intentional climatic geoengineering would involve us in some truly awesome collective decisions, which we have only just begun to evolve the international governance structures to manage. But if we want the Anthropocene to resemble the Holocene rather than the Eocene (roughly 55–35 million years ago, which was several degrees hotter and had neither ice caps nor humans) we will need to act fast. On climate change, meeting the proposed planetary boundary means being carbon-neutral worldwide by mid-century, and carbon-negative thereafter. The former will not be possible in my view without nuclear new-build on a large scale, and the latter will need the deployment of air-capture technologies to reduce the concentration of ambient CO

. On biodiversity loss, we need to rapidly scale up ‘payments for ecosystem services’, schemes that use private and public-sector approaches to make planetary ecological capital assets like rainforests and coral reefs worth more alive than dead. To meet the other boundaries we will need to deploy genetically engineered nitrogen- and water-efficient plants, remove unnecessary dams from rivers, eliminate the spread of environmental toxins like dioxins and PCBs, and get much better at making and respecting international treaties. We can learn a great deal from the success of ozone-layer protection, which remains a shining example of how to do it right.

Most importantly, environmentalists need to remind themselves that humans are not all bad. We evolved within this living biosphere, and we have as much right to be here as any other species. Through our intelligence, Mother Earth has seen herself whole and entire for the first time from space

(#litres_trial_promo). Thanks to us she can even hope to protect herself from extraterrestrial damage: we now operate a programme to track large meteorites like the one that destroyed a significant portion of the biosphere at the end of the Age of Dinosaurs. The Age of Humans does not have to be an era of hardship and misery for other species; we can nurture and protect as well as dominate and conquer. But in any case, the first responsibility of a conquering army is always to govern.

Chapter One

The Ascent of Man

Three large rocky planets orbit the star at the centre of our solar system: Venus, Earth and Mars. Two of them are dead: the former too hot, the latter too cold. The other is just right, and as a result has evolved into something unique within the known universe: it has come alive. As Craig Venter and his team of synthetic biologists have shown, there is nothing chemically special about life: the same elements that make up our living biosphere exist in abundance on countless other planets, our nearest neighbours included. But on Earth, these common elements – carbon, hydrogen, nitrogen, oxygen and many more – have arranged themselves into uncommon patterns. In the right conditions they can move, grow, eat and reproduce. Through natural selection, they are constantly changing, and all are involved in a delicate dance of physics, chemistry and biology that somehow keeps Earth in its Goldilocks state, allowing life in general to survive and flourish, just as it has done for billions of years.

Why the Earth has become – and has remained – a habitable planet is one of the most extraordinary stories in science. Whilst Venus fried and Mars froze, Earth somehow survived enormous swings in temperature, rebounding back into balance whatever the initial cause of the perturbation. Venus suffered a runaway greenhouse effect: its oceans boiled away and most of its carbon ended up in the planet’s atmosphere as a suffocatingly heavy blanket of carbon dioxide. Mars, on the other hand, took a different trajectory. It began life warm and wet, with abundant liquid water. Yet something went wrong: its carbon dioxide ended up trapped for ever in carbonate rocks, condemning the planet to an icy future from which there could be no return.

(#litres_trial_promo) The water channels and alluvial fans that cover the planet’s surface are now freeze-dried and barren, and will remain so until the end of time.

Part of the Earth’s good fortune obviously lies in its location: it is the right distance from the sun to remain temperate and equable. But the distribution of Earthly chemicals is equally critical: our greenhouse effect is strong enough to raise the planet’s temperature by more than 30 degrees from what it would otherwise be, from –18˚C to about 15˚C today on average – perfect for abundant life – whilst keeping enough carbon locked up underground to avoid a Venusian-style runaway greenhouse. Ideologically motivated climate-change deniers may rant and obfuscate, but geology (not to mention physics) leaves no room for doubt: greenhouse gases, principally carbon dioxide (with water vapour as a reinforcing feedback), are unquestionably a planet’s main thermostat, determining the energy balance of the whole planetary system.

This astounding 4-billion-year track record of self-regulating success makes the Earth unique certainly in the solar system and possibly the entire universe. The only plausible explanation is that self-regulation is somehow an emergent property of the system; negative feedbacks overwhelm positive ones and tend to push the Earth towards stability and balance. This concept is a central plank of systems theory, and seems to apply universally to successful complex systems from the internet to ant colonies. These systems are characterised by near-infinite complexity: all their nodes of interconnectedness cannot possibly be identified, quantified or centrally planned, yet their product as a whole tends towards balance and self-correction. The Earth that encompasses them is the most complex and bewilderingly successful system of the lot.

One of the pioneers in understanding the critical regulatory role of life within the Earth system was the brilliant scientist and inventor James Lovelock. Lovelock’s original Gaia theory – that living organisms somehow contrive to maintain the Earth in the right conditions for life – was a stunning insight. But his idea of the Earth as being alive, perhaps as a kind of super-organism, only holds good as a metaphor. Self-regulation comes about not for the benefit of any component of the system – living or non-living – but by dint of the overall system’s long-term survival and innate adaptability.

An important characteristic of the Earth system is that its main elements move around rather than all ending up in one place. Water, for instance, cycles through rivers, oceans, ice caps, the atmosphere and us. An H

O molecule falling in a snowstorm on the rocky peak of Mount Kenya may have been exhaled in the dying gasps of Queen Elizabeth I: water, driven by energy, is always circulating. Nitrogen, oxygen, phosphorus, sodium, iron, calcium, sulphur and other elements are also perpetually on the move. Carbon is perhaps the most important cycle of all, because of the thermostatic role played by its molecular state; particularly in its gaseous form as CO

, but also in combination with other elements, such as with hydrogen as CH

(methane). It was the failure of the carbon cycle that doomed Venus and Mars, yet here on Earth various feedbacks have kept the system in relative balance for billions of years – even altering the strength of the greenhouse effect to offset the sun’s increasing output of radiation over geological time.

Over million-year timescales, the carbon cycle balances out between the weathering of rocks on land, which draws carbon dioxide out of the air, and its emission from volcanoes. Carbon is deposited in the oceans and then recycled through plate tectonics, as oceanic plates subduct under continental ones, providing more fuel for CO

-emitting volcanoes. The process is self-correcting: if volcanoes emit too much carbon dioxide, the Earth’s atmosphere heats up, increasing weathering rates and drawing down CO

. If carbon dioxide levels fall low enough for weathering to cease – as perhaps was the case during the early ‘snowball Earth’ episodes, when global-scale ice caps put a stop to the weathering of rocks – volcanic emissions continue uninterrupted, allowing CO

to build up until a stronger greenhouse effect melts the ice and allows balance to be restored. The system is stable but not in stasis: the geological record shows tremendous swings in temperature and carbon dioxide concentrations over the ages, though always within certain boundaries.

Perhaps one of the strongest arguments against the Gaia concept is the fact that even if the planet in general remains habitable, things do sometimes go badly wrong. Over the last half-billion years since complex life began there have been five serious mass extinctions, the worst of them wiping out 95 per cent of species alive at the time. Most appear to have been linked to short-circuits in the carbon cycle, where volcanic super-eruptions led to episodes of extreme global warming that left the oceans acidic and depleted in oxygen, and the land either parched or battered by merciless storms. And yet, over millions of years, new species evolved to fill the niches vacated by extinguished ones, and some kind of balance was restored. Over the last million years, recurrent ice ages demonstrate how regular cycles can lead to dramatic swings in temperature, as orbital changes in the Earth’s motion around the sun lead to small differences in temperature, which are then amplified by carbon-cycle and ice-albedo (reflectivity) feedbacks. Our planet may be self-regulating, but it is also extraordinarily dynamic.

GOD SPECIES OR REBEL ORGANISM?

Life is now an important component of most of the planet’s major cycles. The majority of carbon is locked up in calcium carbonate (limestone) rocks, laid down in the oceans by corals and plankton. The appearance of photosynthesis was perhaps one of life’s most miraculous innovations, allowing microbes – and later, green plants – to use atmospheric carbon dioxide as a source of food. Water is an essential part of the process: in cellular factories called chloroplasts, plants split water into hydrogen and oxygen, combining the hydrogen with carbon from the air to form carbohydrates, and releasing oxygen as a waste product. The process opened up an opportunity for the evolution of animals, that could eat the carbohydrates as a food source and recombine them with oxygen (forming CO

and water), thereby generating energy and closing the loop.

Evolution of life is a critical part of the process of planetary self-regulation, because it allows organisms to change to take advantage of new opportunities and learn from failures – evolution is self-correction in action. Just as the build-up of oxygen in the air allowed animal life to appear, so the accumulation of any waste is an opportunity for new species to evolve to take advantage of it. Evolution is very different from mere adaptability, because it allows new life-forms to appear rather than old ones to adapt, leading to much greater transformations. A species may, for example, be able to adapt to a shift in its food supply by moving, but over many millennia an entirely new species may thereby come into being, able to exploit a whole new niche in the ecosystem. Think of polar bears, likely descended from an isolated population of brown bears in an ice age, but which evolved white fur and an ice-based lifestyle to become the pre-eminent hunter of the far north.

All this sounds comforting. The Earth, and life, will always prevail. But the self-regulating system contains a flaw, one that can seriously damage or even destroy it. This flaw is the gap in time between a perturbation and the ensuing correction: instabilities can happen very fast, whilst the correcting process of self-regulation typically takes much longer. The gap between the advent of an oxygen-rich atmosphere and the appearance of animal life was a long one: a good hundred million years if not more. Major volcanic eruptions may release trillions of tonnes of carbon dioxide over just a few thousand years, outstripping the capacity of the Earth system to mop up the additional CO

via rock weathering and other processes of sequestration, and leading to extreme global warming events. Mass extinctions happen because changing circumstances outstrip the adaptability of existing species before evolution can work its magic. Over millions of years new species can appear, but only from the diminished gene pool of the survivors – and a return to true pre-extinction levels of biodiversity may take much longer, if it ever takes place at all.

This time-lag effect was cleverly demonstrated in a modelling simulation undertaken by two British researchers, Hywell Williams and Tim Lenton (both at the University of East Anglia; Lenton is a member of the planetary boundaries expert group).

(#litres_trial_promo) In a computer-generated world – entirely populated by evolving micro-organisms living in a closed flask – Williams and Lenton found that the closing of nutrient loops emerged as a robust property of the system nearly every time the model was run. As in the real world, the emergence of self-regulation came about because evolution allowed new species to appear that could use the waste of one species as food for themselves, recycling nutrients and leading to a stable state. Moreover, the more species that evolved, the greater the amount of recycling and the greater the overall biomass the system could support. ‘Flask world’ had discovered the value of biodiversity.

But this world also had a dark side, for several simulations illustrated that the flaw in self-regulation – the time gap between a disturbance and the evolved correction – might occasionally be fatal. In just a few model runs, an organism appeared that was so spectacularly successful in mopping up nutrients that its numbers exploded and its wastes built up to toxic levels before other organisms were able to evolve a response. Williams and Lenton dubbed these occasional rogue species ‘rebel organisms’. They were unusual, but their impact was invariably catastrophic: the explosive initial success of the rebels changed the simulated global environment so suddenly and dramatically that their compatriots were killed, and – with no other life-forms around to recycle their wastes – they were themselves condemned to die too. As the last lonely rebels perished, their whole biosphere went extinct, evolution ceased, self-regulation failed, and life wiped itself out.

Like Lovelock’s Gaia, Flask world – and its rebel organisms – might just be a clever idea, more of a metaphor than a true representation of reality. But the parallels with our species are unsettling. We have transformed our environment within just a few centuries in ways that are wiping out other life-forms at a shocking speed – the changes so rapid that evolution has no time to adapt and thereby allow other organisms to survive. Like a rebel organism, our species discovered a colossal new source of energy, which had lain hidden and undisturbed for millions of years, and which no previous life-form had found a use for. It is the sheer rapidity in the rise of the waste from the exploited new energy source of buried carbon – largely in the form of gaseous carbon dioxide – plus the other combined wastes and environmentally transformative impacts that fossil fuels allowed humanity to achieve, that have now begun to overwhelm the self-regulatory capacity of the Earth system. This single element holds the key to a possible future mass extinction.

Flask world is now our world. Consider that our wastes are accumulating so fast in the oceans that no species can consume them; instead, massive dead zones are spreading around the world’s coasts, from China to the Gulf of Mexico, where the recent BP oil spill adds to the toll. We have produced novel organic chemicals and synthetic polymers that no microbes have yet learned to digest, and which are poisonous to most organisms – often including ourselves. And we are steadily eating our way through global biodiversity – from fish to frogs – consuming voraciously, and moving on to the next species when one is extinguished. Those species that are not edible we ignore and displace, whilst those that threaten or dare to compete with us we pursue mercilessly and annihilate. Thus is our rebel nature revealed.

There is a paradox however. Even as a putative rebel organism, humanity is a product of Darwinian evolution, like every other naturally generated life-form sharing our planet today. Moreover, we did not evolve the biological capacity to eat coal and drink oil – the energy from these abundant ‘nutrients’ is combusted outside the body rather than metabolised within it. Why us, then? Our mastery of fire was a product of the adaptability and innovativeness with which evolution had already equipped us long before, and that no other species had heretofore possessed. Humanity’s Great Leap Forward was not about evolution, but adaptation – and could therefore move a thousand times faster.

I don’t want to oversimplify: the Stone Age did not end in 1764 with James Watt’s invention of the steam engine. Clearly great leaps in human behaviour and organisation took place over preceding millennia with the advent of language, trade, agriculture, cities, writing and the myriad other innovations in production and communications that laid the foundations for humanity’s industrial emergence. But I would argue that the true Anthropocene probably did begin in the second half of the eighteenth century, for it was then that atmospheric carbon dioxide levels began their inexorable climb upwards, a rise that continues in accelerated form today. This date also marks the beginning of the large-scale production of other atmospheric pollutants and the planet-wide destabilisation of nutrient cycles that also characterise this new anthropogenic geological era.

Take population. When humans invented agriculture, some 10,000 years ago, the global human population was somewhere between 2 and 20 million

(#litres_trial_promo). There were still more baboons than people on the planet. By the time of the birth of Christ, the globe supported perhaps 300 million of us. By 1500, that population had increased to about 500 million – still a relatively slow growth rate. A global total of 700 million was reached in 1730. Then the boom began. By 1820 we numbered a billion. That total rose to 1.6 billion by 1900, and the growth rate continued to accelerate. By 1950 we were 2.5 billion strong, and by 1990 had doubled again to more than 5 billion. In 2000 the 6 billion mark was passed. At the time of writing, in late March 2011, we number an astonishing 6.88 billion individuals.

(#litres_trial_promo) Through the process of writing this book, another 225 million people were added to the total – just under half the entire world population of 500 years ago, now appearing in just three years.

But this still doesn’t answer the puzzle: Why us? And why were buried stores of carbon the ‘nutrients’ that allowed our species to proliferate so explosively? A satisfactory response requires a brief digression into the evolutionary origins of this remarkable hominid, for it is our past that holds the key to our present and future. This is the story of a species whose biological characteristics combined with an accident of fate to have world-shattering consequences. And it is a story that might shed some light on the central question of this book – whether we are rebel organisms destined to destroy the biosphere, or divine apes sent to manage it intelligently and so save it from ourselves.

Perhaps the environmentalist and futurist Stewart Brand put it best when he wrote these words: ‘We are as gods and have to get good at it.’

(#litres_trial_promo) Amen to that.

THE DESCENT OF MAN

Listening to some environmentalists talk, it is easy to get the feeling that humanity is somehow unnatural, a malign external force acting on the natural biosphere from the outside. They have it wrong. We are as natural as coral reefs or termites; our inherited physiology is entirely the product of selective pressures operating over millions of years within living systems. Our inner ear, for example, was once the jawbone of a reptilian ancestor. Babies in the womb begin life with tails, expressing in the earliest stages of life genes that illustrate our long evolutionary history. Our key biological characteristics – including those that have allowed us to emerge as ‘sapient’ beings – exist only because they conferred on our ancestors some selective advantage as they ate, fought, played and reproduced over millions of years within the natural biosphere.

The actual origin of life – how animate organisms assembled themselves out of inanimate chemicals without a Dr Venter to supervise affairs – remains a mystery. Perhaps the first self-replicating amino acids were formed in some primordial soup by a charge of lightning or a volcanic eruption. Or maybe, given the right environment and ingredients, life can spontaneously appear. Some suggest that extraterrestrial microbes may have hitched a lift onto the early Earth from passing meteors or comets. Either way, the first microbes appeared about 3.7 billion years ago, evolving into ‘eukaryotic’ cells – with a proper nucleus, cell walls and the capacity to metabolise energy – a billion and a half years later. These cells were probably made up of a symbiotic union of several bacteria, which is why mitochondria in our body cells today still have their own DNA. (Symbiosis, by the way, is quite as much part of the story of evolution as red-in-tooth-and-claw competition.)

Some of these early microbes, the cyanobacteria, learnt to use photons from the sun to split water and carbon dioxide in photosyn-thesis. They are probably Earth’s most successful organisms, for cyanobacteria are still prolific today. As eukaryotic cells learned to combine to form multicellular organisms, the stage was set for a major proliferation of life – though still only in the oceans – in an event dubbed the ‘Cambrian explosion’ by palaeontologists. During the Cambrian, from 540 million years ago, recognisable ancestors of many of today’s animal groups appeared. These include arthropods (insects, spiders and crustaceans), molluscs (snails, oysters, octopus), and even early vertebrates – the first fish. An evolutionary arms race kicked off, as predators evolved ways to catch, grip and swallow, whilst prey developed speed or armour to reduce their chances of being eaten.

Of all the technical novelties evolution called into existence, from scales to jaws, perhaps the most interesting is the development of sight. The eye may have been the innovation sparking this intense burst of Cambrian competition, for both predators and prey would have had an equally powerful reason to evolve vision. The fossil record demonstrates that sight evolved independently in different groups of animals, though in a remarkably similar way. The octopus, for example, has an eye much like ours, with a lens and a retina behind it, yet our common ancestor was probably some kind of sightless worm. All the higher animals that survived the Cambrian could see.