The Sixth Extinction – An Unnatural History (2014)

In ordinary times – by which I mean every single geological epoch minus the present one – species extinction takes place only very rarely.   The “background extinction rate” for mammals (the best-studied group) has historically been approximately 0.25 per million species-years.  Translated that means that since there are about 5,500 mammal species alive today, at the background extinction rate, you would expect one species to disappear every seven hundred years.

That average is, however, distorted by the mass extinction events that have certainly occurred throughout planet earth’s history.  As you may have guessed from the title of Elizabeth Kolbert’s Pulitzer Prize-winning book, we are confident that at least five mass extinction events have previously occurred.  Kolbert, an environmental journalist by trade, defines a mass extinction event as “an event that eliminates a significant proportion of the World’s biota in a geologically insignificant amount of time.”  Spoiler alert: Kolbert has collected some evidence that we may be in the midst of the sixth.

Background and Dinosaurs

Looking back on the scientific understanding of extinction events, it is worth noting that Darwin’s theory evolution has been used to explain both how species originated and how they vanished.  Extinction and evolution were to each other like the two strands of the double helix on which DNA is written.  “The appearance of new forms and the disappearance of old forms” were, Darwin wrote, “bound together.”  Driving both was the “struggle for existence”, which rewarded the fit and eliminated the less so.

The End-Cretaceous (or K-T) extinction event is the most well-known of the five recognised mass extinction events because it is the most recent and, more likely, because it allowed Steven Spielberg to come up with Jurassic Park.  Whilst not as well-known, the other four mass extinction events have been equally if not more devastating.

In addition to the five major mass extinctions, there is evidence to support the notion that there are also much more regular, but less severe extinction events.  A study presented by Kolbert suggests that when mass and lesser extinction events are viewed together, Earth’s history appears to follow a pattern in which an extinction event of some magnitude takes place at regular intervals of roughly 26 million years.

Stepping back again, we can see from the graph below that earth’s biodiversity shows a great expansion in the number and variety of life forms that have come to call this planet home over the last 4.5 billion years. 

(Paleozoic (ancient life), Mesozoic (middle life) and Cenozoic (new life))

When the diversity of life expands, the reciprocal event must be that more species are likely to become extinct, at least according to the Darwinian theory of extinction.  Yet, there is a distinct lack of consensus amongst the scientific community when it comes to the causes of extinction.  One of the most prominent themes in Kolbert’s book is that if 25 years ago it seemed that all mass extinctions would ultimately be traced to the same cause, now the reverse seems true.  Whilst some extinction events are thought to have been caused by glaciation or changes to ocean chemistry, others are can be traced to extraneous causes like asteroid impact, whilst others are a combination of the above.

Take, for example, the extinction of the dinosaurs that occurred approximately 65 million years ago (the K-T).  The most contemporary hypotheses propose that the main cause was not the impact of an asteroid or even the immediate aftermath, but the dust.

It is now thought that an asteroid hit the Yucatan Peninsula at a speed approaching 45,000 miles per hour.  A vast cloud of searing vapour and debris then raced over the continent, expanding as it moved and incinerating anything in its path.  In the process, the asteroid blasted more than 50 times its own mass of pulverised rock into the air.  As the ejecta fell back through the atmosphere, it lit the sky and generated enough heat to, in effect, broil the surface of the planet.  As catastrophic as this event must have been, it would not have been enough to kill all the dinosaurs.  Instead, owing to the composition of the Yucatan Peninsula, the dust thrown up was rich in sulphur which then formed sulphate aerosols that blocked the sun and caused a multi-season “impact winter” which slowly killed off the remaining dinosaurs and precipitated a several million year period in which almost all marine and forest ecosystems completely collapsed.

Anthropocene

If the causes of previous extinction events are still being debated, Kolbert is much more confident regarding the current predicament.

What is sometimes labelled neo-catastrophism, but is mostly nowadays just regarded as standard geology, holds that conditions on earth change only very slowly, except when they don’t.  In this sense the reigning paradigm of life on earth can be summarised as “long periods of boredom interrupted occasionally by panic”.  Though rare, these moments of global panic are disproportionately important.  They determine the pattern of extinction, which is to say, the pattern of life.

The present moment of panic aligns in geology with the Anthropocene epoch.  As detailed in Paul Crutzen’s essay, “Geology of Mankind”, the term “Anthropocene” means the human-dominated geological age.  Among the most radical geological changes that have occurred in the Anthropocene are:

• Human activity has transformed between a third and a half of the land surface of the planet;
• Most of the world’s major rivers have been dammed or diverted;
• Fertilizer factories produce more nitrogen than is fixed naturally by all terrestrial ecosystems (the process by which nitrogen in the atmosphere is converted into ammonia for living organisms);
• Fisheries have removed more than a third of the primary production of the oceans’ coastal waters; and
• Humans use more than half of the world’s readily accessible fresh water runoff.

Currently, about 50 million square miles of land on the planet is ice-free, and this is the baseline that’s generally used for calculating human impact.  According to a recent study published by the Geological Society of America, people have “directly transformed” more than half of this land – roughly 27 million square miles – mostly by converting it to cropland and pasture, but also by building cities, shopping malls and reservoirs, and by logging, mining and quarrying.  Of the remaining 23 million square miles, about three-fifths is covered by forest and the rest is either high mountains, tundra or desert.

Consequently, since humans first emerged approximately 200,000 years ago, ecosystems around the world have changed remarkably quickly (at least in geological terms).   But why should such a change be issue?  As Darwin would posit, the strongest will surely adapt.

The primary issuing is one of extremely accelerated mixing of species.   For millions of years, species moved only as fast as their legs or wings could carry them.  The process of mixing the world’s flora and fauna was thus a slow and gradual one.  However, as early human migration began to establish new routes and methods, the game has changed completely.  In recent decades, the accelerated mixing of flora and fauna via human intervention has reached the point where, in some parts of the world, non-native plants now outnumber native ones.  In fact, during any given 24-hour period, it is estimated that 10,000 different species are being moved around the world just in ballast water.  Thus a single supertanker (or, for that matter, a jet passenger) can undo millions of years of geographic separation.

From the standpoint of the world’s biota, global travel and commerce represent a radical new variable.  Around 200 million years ago, the entire planet’s biota lived on the supercontinent of Pangea.  Whilst there was no water to physically prevent the mixing of species, they did so slowly.  Over millions of years the continental plates drifted apart and segregated many species, allowing them to develop their own niches and to thrive.  Now, in the geological blink of an eye, we are seeing all the continents’ species being mixed back together at incredible speed.

Kolbert presents several lines of evidence that argue in favour humans being the cause of accelerated patterns of species extinction around the world.  The most compelling of these is timing.  The megafauna extinction that began at the end of the last ice age, and which caused the world to lose its population of 14 foot mammoths and mastadons, and rodents that weighed up to 700 kgs, did not take place all at once.  Rather, it occurred in pulses.  The first pulse, about 40,000 years ago, took out Australia’s giants.  A second pulse hit North and South America around 25,000 years later.  Madagascar’s giant lemurs, pygmy hippos and elephant birds survived all way into the Middle Ages.  New Zealand’s moas (12 foot tall flightless birds) made it as far as the Renaissance.  It’s hard to see how such a sequence could be squared with a single climate change event.  Instead, the sequence of the pulses and the sequence of human settlement line up almost exactly.

The Anthropocene is usually said to have begun with the industrial revolution, or perhaps even later, with the explosive growth in population that followed WWII.  By this account, it’s with the introduction of modern technologies – turbines, railroads, chainsaws – that humans became a world-altering force.  But the megafauna extinction suggests that we should view the Anthropocene as an age that began more like 40,000 years ago at a much more primitive stage in human history. 

Evidently, we humans have not needed to be technologically advanced in order to cause large extinction events.  Before humans emerged on the scene, being large and slow to reproduce was a highly successful strategy, and outsized creatures dominated the planet.  Then, in what amounts to a geological instant, this strategy became a loser’s game.  And so it remains today, which is why elephants, bears and big cats are in so much trouble.  Though it might be nice to imagine there once was a time in which man lived in harmony with nature, it’s not clear that he ever really did.

Forests and Trees

In the popular imagination, climate change is mostly seen as a threat to cold-loving species.  But climate change is going to have just as great an impact in the tropics.  The reasons for this are complicated, but they start with the fact that the tropics are where most species actually live.

This simple observation is more scientifically referred to as the Latitudinal Diversity Gradient (the LDG, as discovered by Alexander von Humboldt in the early 1800s):  the general rule that the variety of life is most impoverished at the poles and richest at low latitudes.

At the equator, around Columbia, Venezuela, Peru and Brazil there are approximately 1,035 tree species; roughly five times as many as in all of Canada’s boreal forest.  And what holds for trees also holds for birds and butterflies and frogs and fungi.   

Kolbert connects the disparate ideas of the Anthropocene, climate change and the LDG when visiting a researcher by the name of Miles Silman in South America.  Silman has been studying in the Peruvian Amazon for the past two decades where he has recorded the different species of trees and their size within 17 two and a half acre plots arranged along a ridge running from the Amazon basin to the top of the Andes.  Astoundingly, he has found that climate change is driving the average tree genus up the mountain (to cooler temperatures) at a rate of eight feet per year (of course, trees can’t actually move, but they do the next best thing which is to disperse seeds uphill for the next generation).

Silman’s research is like a time capsule that reveals there is slow-motion race taking place between species of trees in the Amazon.  Trees are moving faster than ever previously recorded up the mountainside.  However, many more are learning they are not as fast or strong as their neighbours or that they will be thwarted by human intervention.

That is because one of the defining features of the Anthropocene is that we are segregating and chopping up the land in which the world’s species live by creating barriers – roads, clear-cuts, cities – that prevent species from rehousing themselves after this eviction.  A species that needs to migrate to keep up with rising temperatures has a hard enough time as it is, but the problem is exacerbated when you realise that so many species are racing towards a cliff edge.

The Sea

This problem is clearly not contained to land-faring species either.  Humans are both altering the chemistry of the sea and slicing up the environments in which sea creatures can live.

Sea chemistry is being altered by the excess CO² we emit.  Roughly one-third of the CO² that humans have so far pumped into the air has been absorbed by the oceans.  This comes to a stunning 150 billion tons in less than 100 years (to find CO² levels higher than today’s requires going back to the mid-Miocene, 15 million years ago).  As with most aspects of the Anthropocene, it is not only the scale of the transfer that is significant, but the speed.

As a result of this absorption of CO², the ocean is becoming more acidic and, according to research, ocean acidification played a major role in at least two of the Big Five extinctions (the End-Permian and the End-Triassic) and quite possibly a third (the End-Cretaceous).

But why is ocean acidification so dangerous to species?  Depending on how tightly organisms are able to regulate their internal chemistry, acidification may affect such basic processes as metabolism, enzyme activity and protein function.  Because it will change the makeup of microbial communities, ocean acidification will alter the availability of key nutrients, like iron and nitrogen.  For similar reasons, it will change the amount of light that passes through the water and it will alter the way sound propagates.  It will impact photosynthesis and alter the compounds formed by dissolved metals, often in ways that will be poisonous.

The species most vulnerable to these changes is the coral reef.  A recent study by a team of Australian researchers found that coral cover in the Great Barrier Reef has declined by 50 per cent in just the last 30 years.

Add to this change in chemistry, human-created changes to the physical landscape of the sea and it becomes obvious why sea creatures are going extinct at such an alarming rate.  The roster of perils includes: overfishing, which promotes the growth of algae that compete with corals; agricultural runoff, which also encourages algae growth; deforestation, which leads to siltation and reduces water clarity; and dynamite fishing, whose destructive potential would seem to be self-explanatory.  If you thought that the ocean would be safe from human intervention, the data suggests otherwise.

Amphibians

Whilst Kolbert takes a fairly broad brush approach in describing the plight of most species in the forests and in the seas, the point is driven home by the specific example of amphibians.

Amphibians emerged at the time of the supercontinent, Pangea.  Since the breakup of Pangea, they’ve adapted to conditions on every continent except Antarctica.

Yet, within the last two decades, a micro-organism (a fungus from the chrytids family called Batrachochytrium Dendrobatidis or Bd for short) has been found to be living on amphibians’ skin and killing them off at an incredible rate.  Bd interferes with amphibians’ ability to take up critical electrolytes through their skin.  This causes them to suffer what is, in effect, a heart attack.

Worringly, Bd is everywhere and appears to be unstoppable at present.  Its origin is presently unknown.  The plight of amphibians is such that, as a result of the spread of Bd, there is a group called EVACC (El Valle Amphibian Conservation Centre) operating in Costa Rica and Panama to attempt to capture a male and a female of every species of amphibian (like an Amphibian Noah’s Ark).

One theory as to how Bd is moving is that it has been moved around the globe with shipments of African clawed frogs, which were used in the nineteen fifties and sixties in pregnancy tests.

A second theory is that the fungus was spread on North American bullfrogs which are often exported for human consumption.

Either way, the etiology is the same: human activity.  Without being loaded by someone onto a boat or a plane, it would have been impossible for a frog carrying Bd to get from Africa to Australia or from North America to Europe.

Consequently, amphibians now enjoy the dubious distinction of being the World’s most endangered class of animals; it has been calculated that the group’s current extinction rate could be as much as 45,000 times higher than the background rate. 

Conclusion

Beyond amphibians, Kolbert presents data to suggest that the extinction rates around many other groups are approaching similar levels.  It is established that one-third of all reef-building corals, a third of all freshwater mollusks, a third of sharks and rays, a quarter of all mammals, a fifth of all reptiles and a sixth of all birds are headed toward oblivion.

Ultimately though, Kolbert falls on her own sword.  By Kolbert’s own admission, this is not the sixth mass extinction event that the title of the book would suggest.  Climate change alone is unlikely to generate a mass extinction as large as one of the Big Five.  However, there is a high likelihood that climate change on its own could generate a level of extinction on par with or exceeding the slightly “lesser” extinction events of the past and be the end of so many precious species across the world.

Cause for alarm is heightened when you consider how human behaviour could add to the rising extinction rates caused by climate change.  The primary human sin in this regard is the accelerated speed at which we are constantly transporting non-native species to new environments.

Kolbert argues that, as soon as humans started using signs and symbols to represent the natural world, they pushed beyond the limits of this world.  So if you want to think about why humans are so dangerous to other species, you can picture a poacher in Africa carrying an AK-47 or a logger in the Amazon gripping an axe, but better still, you can picture yourself, holding a pen.  For Kolbert’s conclusion is somewhat paralysing: extinction is inevitable for every species, but humans are a quite unique species in that our mastery of our minds and the world around us may ultimately lead us to live on a very lonely planet.

Feral (2013)

When one of The Guardian’s chief environmental writers publishes a book called Feral you have to get a few chapters in before you can relax that the book isn’t going to descend into anti-capitalist anarchy.  Fortunately, George Monbiot has written an impassioned account of the arguable need to return to a more wild way of caring for the ecosystems of the world.  Unfortunately, it does suffer from a wanton disregard for the people who currently make their living farming the land (and hence descends dangerously close to anti-capitalist anarchy).  But, perhaps that is precisely his point.

Just as Feral is a book about competing interests (those who seek to manage the natural world versus those who seek a more laissez-faire approach), Feral is also a book with competing halves (how we have come to live in a world less wild versus how we can live in a world more wild in the future).  Monbiot’s founding principle is that humans have always caused the degradation of the natural world and the collapse of nonhuman populations.

Even a cursory study of human history proves this to be true.  Whenever people broke into new lands, however rudimentary their technology and small their numbers, they soon destroyed much of the wildlife – especially the numbers of larger animals – that lived there.  There has never been a state of grace or a golden age in which people lived in harmony with nature.  The spur to action is that the 21^st century has seen a significant acceleration in both trends.  This is so much so that now not even the planet’s oceans are safe from human impact.  In fact, the world’s continental shelves are being trawled at 150 times the rate at which forests on land are cleared.

It is clear that wherever human populations have exploded, nonhuman populations and ecosystems have conversely crashed.

Rewilding

Monbiot’s panacea to this timeless but also most modern of problems is that of “rewilding”.

As Monbiot puts it, “Rewilding is about resisting the urge to control nature and allowing it to find its own way.  It involves reintroducing absent plants and animals (and in a few cases culling exotic species which cannot be contained by native wildlife), pulling down the fences, blocking the drainage ditches but otherwise stepping back.  At sea it means excluding commercial fishing and other forms of exploitation.  The ecosystems that result are best described not as wilderness, but as self-willed: governed not by human processes but by their own processes.  Rewilding has no end point, no view about what a right ecosystem or a right assemblage of species looks like.  It does no strive to produce a heath, a meadow, a kelp garden or a coral reef.  It lets nature decide.”

Well, doesn’t that sound grand? But even the most ardent of environmentalists would have a hard time with the notion that we should just let the grass grow and live in a state of complete naturalness.  The roads, shopping malls, housing estates and skyscrapers have been built and, for better or worse, our modern lives are in turn built around them.  At first glance, Monbiot’s idea seems to fly in the face of the inexorable march of progress, to hark for a simpler time, and I was left questioning: can you put the genie back in the bottle?

However, throughout Feral, two rationales are presented to argue that the rewilding of natural ecosystems is not an attempt to restore them to any prior state or to prevent the functioning of modern society, but instead just to permit ecological processes to resume to enable modern life to co-exist harmoniously with natural life.  Instead, rewilding is about improving what wild areas we do have.

Rationale for Rewilding – Number 1

The first idea underpinning rewilding efforts is that of “Shifting Baseline Syndrome”.

Shifting Baseline Syndrome is a dressed up way of saying that the people of every generation perceive the state of the ecosystem they encountered as a child to be the norm.  When fish or animals are depleted, campaigners or scientists usually call for them to be restored to the levels that existed in their youth: their own ecological baseline. 

The silent but dangerous by-product of such a short historical perspective is that the bounty of nature is slipping away in front of our eyes without anybody able to notice.  Consequently, we are all unaware that what was considered normal when we were children was in fact a state extreme depletion.  Over generations, this has caused a huge but largely imperceptible decrease in the number of fauna and flora that grace almost all the planet’s ecosystems. 

Monbiot presents compelling data to evidence that, until relatively recently, large animals lived almost everywhere on the planet and often in great numbers.  Additionally, large species have been excluded from temperate regions not by any natural, ecological or physiological constraints, but by humans.

Shifting Baseline Syndrome prevents us all from appreciating such a seismic shift and is leading us dangerously close to a relatively sparse natural world.

Rationale for Rewilding – Number 2

But why is an imperceptible decrease in large species important?  The answer, according to Monbiot, lies in the unappreciated significance of trophic diversity.

Trophic means relating to food and feeding.  Restoring trophic diversity means increasing the number of opportunities for animals, plants and other species to feed on each other.  It means increasing the number of trophic levels (top predators, middle predators, plant eaters, plants, carrion and detritus feeders) and creating opportunities for the number and complexity of relationships at every level to rise.

When large species at the top of a foodchain are hunted or their habitats are destroyed with the result that their numbers decrease significantly, a trophic cascade is likely to occur where the population of each species beneath it in the foodchain also decreases. 

At first I found the idea of a trophic cascade to be counterintuitive.  Surely when your chief predator dies off, those animals that were formally prey should be able to thrive.  However, Monbiot’s presentation of a new school of ecological thinking is hard to argue with.

The old belief among ecologists was that natural systems were controlled only from the bottom up: that the abundance of plants controls the abundance of plant eaters, which controls the abundance of meat eaters.  The new understanding is that top predators, large herbivores and keystone species (ones that have a larger impact on its environment than its numbers alone would suggest) unwittingly re-engineer the environments in which they live.  In some cases they change not only the ecosystem but also the nature of the soil, the behaviour of the rivers, the chemistry of the oceans and even the composition of the atmosphere.

The beaver is one of several missing animals in the UK that has been described as a keystone species.  A beaver is a keystone species because its activities radically change the behaviour of a river.  They slow it down.  They reduce scouring and erosion.  They trap much of the load it carries, ensuring that water runs more clearly.  They create small wetlands and boggy areas.  They make it more structurally diverse, providing homes for many other species.  Far from spreading disease, their dams filter out the sediments containing faecal bacteria.  Consequently, the beaver creates many of the conditions that allow other species to live.  So conversely, when beaver numbers are drastically reduced, so are many of the species that live in the river or on the river bank.

Similar stories can be seen at sea as well as on land.  Perhaps the most famous trophic cascade in the seas took place along the eastern rim of the Pacific, where sea otters, once widespread and abundant, were almost wiped out by both native people and fur traders.  The result was the near-disappearance of the coastal ecosystem.  Sea otters prey on urchins, among other species.  Sea urchins graze on kelp, the long and leathery seaweed that, in the right conditions, produces tall, dense undergrowths reminiscent of terrestrial forests.  These harbour a wonderful variety of fish and other creatures.  Consequently, when the sea otters were nearly wiped out, so was much of the fish life that lived in the same ecosystem.

Likewise, as whale numbers have declined, so have those of krill: to just one-tenth of their volume before the 1980s.  Their collapse, until recently, mystified observers.  It now seems that the whales, by diving down through the water column, perform an essential role in circulating nutrients up to the surface waters and thereby feeding the krill.  If undisturbed by whales, the plant plankton that the krill feed on would sink out of sight, beyond the photic zone (the waters in which the light is strong enough to permit plants to grow).  Furthermore, the nutrients contained within the plankton sink, becoming unavailable to most other lifeforms.  Consequently, as whale numbers are reduced, the surface waters rapidly become depleted of essential minerals, especially iron, whose scarcity limits growth more generally.

The natural conclusion is that an ecosystem lacking in trophic diversity (and particularly top predators, large herbivores or keystone species) is one that lacks the interconnection between species that creates abundance and robustness.  Reintroducing these species can therefore create the right conditions in which nature’s bounty may be (somewhat) restored.

A Plan to Reintroduce Animals in the UK

With that rationale in mind, Monbiot presents a fascinating review of the species that we may wish to reintroduce in order to restore the health and wealth of the wild areas of the UK.  I have reproduced a copy of the review’s most interesting entries in a table below, all of which at some point in history roamed the wilds of the UK (I was shocked to learn that the elephant bones were excavated from under Piccadilly Circus).

Now however, according to the Cairngorns Wildcat Project, the UK is the largest country in Europe, and almost the whole world, which no longer possesses any of its big carnivores.  The reintroduction of just a few of the species suggested below may go a long way to making the UK a more bountiful environment.

Name of species	Approximate date of extinction in Britain	Suitability for reintroduction (out of 10)	Reintroduction efforts so far
Beaver	Mid 18th century	10	Officially released in the Knapdale Forest, Argyll.
Wolves	1621 AD	7	None.  Risks to people and livestock.
Wild boar	Mid 13th century	10	Four small populations in southern England.
Elk or Moose	1900 BC	10	Released in 200 into a rewilding project in Sutherland
Lynx	600 BC	9	None.  Will kill the occasional sheep.
Lion	8,700 BC (in Netherlands)	1	None.
Elephant	115,000 years ago.  Hunted to extinction in Europe 40,000 years ago.	2	None.
Hippopotamus	100,000 years ago	1	None.  Suitable habitat in short supply.  Can be extremely dangerous.
Grey whale	Remains found off the coast of Devon dating around 1600 AD	7	University of Central Lancashire has a plan to relocate fifty grey whales from the Pacific to the Irish Sea.

The aim of such review is not to advocate for all of their reintroduction into the British wilderness (see the suitability score for each), but instead to expand the range of what people think is possible, to open up the ecological imagination.

Each species would present its own unique challenges and would require a careful PR campaign with the British public in order to explain their benefit to trophic diversity and the overall health of the environment.  However, I am immediately attracted to the reintroduction of the beaver, the elk and the boar.  I believe they would be relatively safe starting points for the UK consciousness regarding excitement about rewilding efforts.

Whilst Monbiot advocates reintroducing wolves into the UK because they kill foxes, reduce disease and assist the owners of grouse moors and deer estates, I am not convinced that the UK public is yet willing to accept an animal known to be so dangerous even if the return of the wolf also makes the introduction of other missing species – such as boar and moose – more viable, as their populations will be checked without the need for human intervention.

Opposition to Rewilding

The public’s reticence to reintroducing potentially dangerous animals into the wild is just one of a few problems I can see with rewilding efforts.

I would argue that the most pressing problem with rewilding is that it is somewhat at odds with the planet’s need to produce more food (see my previous review of The End of Plenty : The Race to Feed a Crowded World for more information about that issue).  Reason being that central to Monbiot’s argument that the habitats for top predators, large herbivores and keystone species are being privately seized is the reason that, particularly in the UK, the farming of livestock takes up that land.   

Specifically, Monbiot takes against Welsh sheep farmers quite aggressively, “Sheep farming in this country is a slow-burning ecological disaster, which has done more damage to the living systems of this country than either climate change or industrial pollution.  Yet scarcely anyone seems to have noticed...Since the Second World War, sheep have reduced what remained of the upland flora to stubble.  In 6,000 years, domestic animals (alongside burning and clearing for crops and the cutting of trees for wood) transformed almost all the upland ecosystems of Britain from closed canopy forest to open forest, from open forest to scrub and from scrub to heath and long sward.  In just sixty years, the greatly increased flocks in most of the upland areas of Britain completed the transformation: turning heath and prairie into something resembling a bowling green with contours.”

Whilst I have sympathy with Monbiot’s position that farming has consistently divided up the land, stripped the soil of its fertility and pushed out other forms of flora and fauna to maximise production of a monoculture, it cannot be said that we produce too much meat or too many crops in this country (or indeed in the world).   Yes, it is true that Wales now possesses less than one-third of the average forest cover of other European countries and, between 1950 and 1999, the number of sheep in Wales rose from 3.8 to 11.6 million, but the recent statistics also indicate that 25 per cent of low income families in the UK struggle to eat regularly.

If the cost of reintroducing the elk to the UK wilderness is a decrease in farmland, resulting in less food supply, higher prices and rising rates of malnutrition or starvation of humans then I am not in favour.  A long term view may suggest that by increasing trophic diversity the foodchain becomes more robust for all species (including humans), the short term reality for starving families would dictate that reintroduction at the expense of farmland can only be an option when we have a food surplus.  For now, any attempts to improve trophic diversity should be done without reference to annexation of farmland. 

The second argument against rewilding is one of psychology. Could it be said that rewilding is actually about alleviating human guilt?  Are we simply reintroducing old species to cover up the sins of our ancestors?  And if rewilding is all about letting nature take its own course, then why do we believe further meddling will undo our previous meddling?

There are many ways in which Monbiot tries to unearth the psychological urge for a wilder, more feral life that do not rely on the exorcism of human guilt regarding the environment: the urge to shop as a foraging instinct, football as a sublimated hunt, violent films as a remedy for unexorcised conflict, the pursuit of ever more extreme sports as a response to the absence of dangerous wild animals, the cult of celebrity chef as an attempt once more to engage with the fruits of the land and sea.  I don’t find any of these to be particularly persuasive.  However, I also don’t care if we are motivated by guilt because I believe the preservation or restoration of nature to be a worthy end in and of itself.

The third argument against rewilding is that puts the cart before the horse.  That is to say, if the object is to protect the wilderness, the first challenge is to curtail commercial deforestation efforts.  Without such curtailment, there will be very few jungles, forests, woods, swamps, mangroves, prairies or reefs in which to reintroduce lost species. 

Motivations for Rewilding

Whilst I am clearly not sold on a full-blooded approach to rewilding, I am sold that the drive towards monoculture causes a dewilding of both places and people.  It strips the Earth of the diversity of life and natural structure to which human beings are drawn.  It creates a dull world, a world lacking in colour and variety, which enhances ecological boredom, narrows the scope of our lives and limits the range of our engagement with nature.

Rewilding would also create a great boon for the green economy.  In the early years, rewilding would require lots of labour: planting trees, reintroducing lost plants and animals, removing fences and controlling exotic invasive species.  As the ecosystem recovered, the rewilding workforce would decline, but the potential for generating money from tourism would rise.  It is possible to envisage a thriving community of wardens and guides, providing bed and breakfasts, farm shops, clay-pigeon shooting, bicycle hire, horse riding, fishing lakes, falconry, archery and all the other services that now help rural communities to prosper.

Conclusion

The environmental movement up till now has been necessarily reactive.  We have been clear about what we don’t like.  But we also need to say what we would like. We need to show where hope lies and ecological restoration could be a work of hope that is mutually beneficial to humans and the environment.

Most human endeavours, unless checked by public dissent, evolve into monocultures.  Money seeks out a region’s comparative advantage – the field in which it competes most successful – and promotes it to the exclusion of all else.  Following this logic, every landscape or seascape performs just one function.  However, the more we understand about how ecosystems work, the less appropriate certain conservation strategies appear to be.  Most conservation strategies focus only on the physical infrastructure – the trees, shrubs and deadwood which provide habitats for many species – and not the connections between species that build an ecosystem.  Consequently, I applaud Monbiot for his efforts in promoting the cause of rewilding in the public discourse and I support the reintroduction of the beaver, the elk and the wild boar back into the UK (and other appropriate species in other ecosystems across the world).  Prior to reading this book, I had very little knowledge of the importance of many species and the on-going efforts to reintroduce them.

Unfortunately, most of the rewilding that has happened on earth so far has taken place as a result of humanitarian disasters.  Therefore, it is time that we support a much more proactive vision of ecosystems that we wish to live in and rely upon.