Now or never: a sustainable future for Australia?

IN THE YEAR FOUR BILLION

We succeeded in taking that picture, and if you look at it, you see a dot. That's here. That's home. That's us. On it, everyone you ever heard of, every human being who ever lived, lived out their lives. The aggregate of all our joys and sufferings, thousands of confident religions, ideologies and economic doctrines, every hunter and forager, every hero and coward, every creator and destroyer of civilisations, every king and peasant, every young couple in love, every hopeful child, every mother and father, every inventor and explorer, every teacher of morals, every corrupt politician, every superstar, every supreme leader, every saint and sinner in the history of our species, lived there on a mote of dust, suspended in a sunbeam.

--CARL SAGAN, 11 May 1996

The image that moved Carl Sagan to such poetic magnificence was taken by Voyager 1 on 14 February 1990. The vessel was 4 billion miles from home--a mile for every year of Earth's existence--when it captured that image, and in it Earth is nothing more than a minute blue dot, all but lost in the immensity of the cosmos. At the time Sagan described our home so beautifully he had just half a trip round the sun--six months--to live; and he well knew that the "mote of dust" that carried him on his life journey is an extraordinary place--for it is the only living planet we know of in all the vastness of the universe.

With the twenty-first century less than a decade old, Sagan's description resonates more powerfully than ever. Our despoliation of Earth's life-support systems seems to mark us destroyer of our own civilisations, and as the planetary crisis we have created deepens, it is certain that no saviour will arise to rescue us from ourselves. There is no real debate about how serious our predicament is: all plausible projections indicate that over the next forty to ninety years humanity will exceed--in all probability by around 100 per cent--the capacity of Earth to supply our needs, thereby greatly exacerbating the risk of widespread starvation, or of being overwhelmed by our own pollution. The most credible estimates indicate that we are already exceeding Earth's capacity to support our species (termed its biocapacity) by around 25 per cent. With global food security at an all-time low, and greenhouse gases so choking our atmosphere as to threaten a global climate catastrophe, the signs of what may come are all around us.

Everyone knows what the solution is: we must begin to live sustainably. But what does that actually mean? "Sustainability" is a word that can mean almost anything to anyone. Whether used by cosmetics advertisers or fruit sellers, it is bandied about as if it were the essence of virtue. Yet so recent is the word that my spellcheck doesn't recognise it.

That increasingly authoritative fount of all knowledge, Wikipedia, defines sustainability as "a characteristic of a process or state that can be maintained at a certain level indefinitely." Hardly a moral definition, this, or indeed--in light of the second law of thermodynamics--a feasible one. Many environmentalists opt for a more practical meaning: "living in such a way as not to detract from the potential quality of life of future generations." And here we find a definition in harmony with the commonly voiced aspiration to "try to leave the world a better place than we found it." This essay is in part an inquiry into the causes of our common failure to realise this heartfelt desire--even though it is one shared by almost every individual on Earth.

If we accept the environmentalists' definition, living sustainably does not involve any particular morality beyond extending the Eighth Commandment (Thou shalt not steal) to future generations. A society that limited itself to such a narrow aspiration could be a barbarous place. Why worry about the distribution of wealth? Why waste a corpse? Any meaningful inquiry into sustainability must surely be broader than this, and thus be as much a philosophical and moral discussion as a scientific one; for sustainability pertains to us--our innate needs and desires--as much as it does to the workings and capacities of our planet. A real search for sustainability involves a broad vision--indeed, it encompasses many flashpoint issues: is there space for meat eating in a sustainable world, for example? And what of animal rights--and human rights--and religion, and democracy, and the free market, and war? While a detailed look at how these issues could be squared with a fully sustainable future is far beyond the scope of this essay, such questions will continually arise as we examine clear, practical solutions to our most urgent problems.

Where does science fit into this inquiry? In human affairs there is often a great difference between aspiration and achievement. Even a society possessed of a moral and philosophical framework ideally suited to attaining a sustainable future may fail to do so if it lacks knowledge of how the world works, and of how its practices and technology are affecting Earth's life-support systems. Accurate scientific knowledge of Earth and its processes is vital to the pursuit of sustainability. And so I propose commencing this investigation with two questions, which, even if they cannot be definitively answered, can nevertheless guide us in our search. What is our purpose as a species? And how does Earth work?

The wellsprings from which we derive meaning in our lives are intensely personal. My own search for meaning has led me to the belief that this generation--those of us living at the dawn of the twenty-first century--is destined to achieve an extraordinary transformation, one unique in the 4-billion-year history of Earth, and one which will influence the fate of life from now on. Geologists talk of the dawning of a new geological period called the Anthropocene, which is characterised by pervasive human influence on Earth processes. But perhaps the Anthropocene will truly have dawned when humanity uses its intelligence to help regulate those processes for the good of Earth as a whole.

It is the great complexity and order created by evolution through natural selection that has led to the existence of Gaia: Earth conceived of as a self-regulating, evolving system. James Lovelock, the originator of the Gaia hypothesis, illustrated the concept by showing how Earth as a whole maintains the temperature of the planet's surface within bounds that are conducive to life, and recycles nutrients and regulates the chemistry of the oceans to the same end. In short, life keeps the atmosphere and oceans out of balance with Earth's rocks in a way that permits life to flourish. The Gaia hypothesis is a way of describing how our living planet as a whole works.

We have long understood--from biblical teaching and practical experience--that we are naught but earth: ashes to ashes, dust to dust, as the English burial service puts it. Indeed, "Dust thou art, and unto dust shalt thou return" (Genesis 3:19) are among the oldest written words to have come down to us. Yet while we have long understood that we are earth, it is equally true, but almost never said, that we are Earth as well. We are Earth by virtue of the fact that every one of us has been shaped by the process of evolution through natural selection: it's that process which spawns the exceedingly complex and highly ordered structures known as life and its ecosystems. And this has a profound implication: Earth was not made for us, rather we were made for this Earth.

This realisation of our purpose is at odds with some of the most powerful currents in our Western civilisation, including the Christian tradition I grew up in. In fact, it is diametrically opposed to them, for it asserts that we are evolved to serve Earth, and that our great and distinguishing characteristic--our intelligence--is not ours alone, but Gaia's as well, and is destined to be used by Gaia for her own purposes. James Lovelock took the name Gaia from the ancient Greeks: it was their term for the earth goddess. I believe that over the course of the twenty-first century we will again come to serve our Earth goddess, perhaps even to revere her.

Looking at the current state of Earth, you might be tempted to see humanity as an enemy of Gaia, but to do so would be a mistake. We are self-evidently part of Gaia, and, just as self-evidently, as animals in the Gaian system we must kill (even if we kill only vegetable matter) in order to survive. Gaia is all about the giving, taking and reprocessing of life. Perceiving ourselves as outside of and antagonistic to Gaia is, I believe, a terrible mistake, for to do so leads us to consider actions necessary for our survival to be somehow wrong. As animals we must eat, and that means taking life. Striving for a bloodless, painless world of pristine morality and zero impact on nature is delusional. Even more importantly, it blinds us to what I believe is the true purpose, according to the Gaian perspective, of our existence.

I believe that the deepest significance of the twenty-first century can be glimpsed in the hierarchical structure of life on Earth. Here lies the potential for sustainability and the transformation of our existence. Guided by evolution, the history of life has been one of increasing complexity and increasing efficiency. The eminent evolutionary biologist Stephen Jay Gould argued that life has not increased in overall complexity because simple life forms such as bacteria still constitute the great mass of life. Yet, viewed from a Gaian perspective, this theory overlooks the undeniable spread and increasing development of life. Life has spread from its origins on the bottom of shallow seas 3.5 billion years ago to almost all parts of Earth's rind. Some 540 million years ago, creatures learned to burrow into the sediments of the sea floor. Then they colonised land, the air and the ocean depths. Furthermore, as life evolved and spread, the reproduction and metabolism of innumerable lineages improved over time, as did the efficiency of bodily command-and-control systems.

Large, highly evolved creatures such as mammals play a disproportionately important role in influencing the carbon cycle and other ecosystem processes. There is no doubt that their evolution has increased Gaia's ability to control planetary life-support systems, for as mammalian metabolism has become more complex and efficient, so has that of the planet as a whole. Six hundred million years ago, when there was little or no complex life, Earth's thermostatic control was so poor that the planet repeatedly froze right to the equator, an event known as "snowball Earth." Since the rise of complex life, such events have not recurred.

Evolution through natural selection is a blind process whose only tools are variation (within populations) and death (of the less well adapted). That's why Richard Dawkins likened its workings to that of a "blind watchmaker." But now, after 4 billion years, the evolutionary process has thrown up a potentially powerful and swiftly responsive command-and-control system that may serve Gaia as a whole. That system is our own human intelligence and self-awareness. It is my belief that we humans are poised to become, from now on, the means by which Gaia will regulate at least some of its essential processes.

Is it right to say that we are Gaia's self-awareness? Gaia's brain? I believe it is. After all, we commonly talk about our own self-awareness, yet rarely question whether our toes, for example, are aware of the beautiful starry night that our brains are taking in. Admittedly, our bodies are far more highly integrated than are Gaia's disparate parts. But it is undeniable that we are a part of the Gaian whole. Whether there is a Gaian meaning to our existence or not, acknowledging that we are an influential part of Gaia requires a change in the way we interact with Earth's life-support processes. After all, brains do not despoil the bodies that they are part of, for to do so is to destroy themselves. Admittedly, brains are expensive to run. Our own brains, which constitute just 2 per cent of our bodies by weight, greedily take around 20 per cent of all the energy we consume. As Gaia's intelligence, humanity will doubtless impose a heavy tithe on the Earth, yet that burden cannot be so great as to bankrupt the system that supports it.

Gaia's potential for intelligent control is exceedingly recent: it arose abruptly towards the end of the twentieth century, after humans had plumbed the depths of the oceans, revealed Earth's internal structure and her history, and photographed her from deep space. Scientists such as Carl Sagan were the first to glimpse the full significance of these achievements, yet such has been our lack of focus on sustainability that even today the great mass of humanity is unaware of their true import.

By the twenty-first century the achievements of these pioneers had opened the way to a limited understanding of how Earth works. Here, scientists such as James Lovelock led the way, and as a result of their efforts we can now describe in some detail how Earth recycles minerals and nutrients, how atmospheric and oceanic chemistry is maintained, how the surface temperature of our planet is regulated, and how biodiversity is protected from external shocks. It was as if, by the late twentieth century, we had finally lifted the bonnet on our planetary vehicle and seen the sophisticated engine concealed within. Then, at the dawn of the new century, we began to understand how it actually worked.

Such deep understanding of Earth's self-regulatory systems is inevitably empowering. Just as surgery could not progress without Harvey's discovery of the circulation of the blood, so humanity could not hope positively to influence Earth's thermostat without knowledge of the carbon cycle. If the twentieth century was the century of technological triumph, then this twenty-first century of ours marks an even more signal moment in planetary history: the century when our knowledge of Earth's processes must be put to use. Within the lifetimes of many people reading this essay, Gaia will pass from an unconscious to a conscious means of control after 4 billion years of self-regulation. Either that or we will fail to achieve sustainability, and Gaia's newly attained consciousness--which is made possible only by our global civilisation--will vanish, perhaps to be lost forever.

It is all too possible that we will fail to achieve sustainability, and that the blind watchmaker will once again wield his tools of variation and death in order to reset the balance of a severely diminished living Earth. Well before we were ready to assume control of the planet, we humans were already influencing Earth processes in ways that threatened global catastrophe. Acting without an awareness of the consequences of our actions, or even a sense of responsibility, we were (from the perspective of Gaia's purpose) immature. Now our fate and that of our planet will be determined by the rate at which we, as a species, can mature and develop a new sense of responsibility. I fear that if we are to avoid catastrophic failure, we will need to learn very fast: learn, indeed, on the job. Our search for sustainability is thus an uncertain experiment, which must inevitably see setbacks and failures. Succeeding at it in the long run will be the greatest challenge we have ever faced.

THE CLIMATE PROBLEM

There was a time, around 100,000 years ago, when there were just 10,000 people on Earth. A century ago there were 1.5 billion of us, and now there are around 6.6 billion. Just forty years from now there will be around 9 billion. With luck and good management, our population will not grow beyond this point. But some estimates see our numbers swelling by a billion or more in the century after that. That's 10,000,000,000 people, on a planet that once held 10,000. Such a burden of human flesh, which all needs to be housed, clothed and fed, will exacerbate all of our environmental woes. Yet who can we ask to get off? The truth is that if we wish to act morally, we can influence population numbers only slowly. So, while it's important to focus on population decrease as a long-term solution, we cannot look to it for answers to the immediate crises.

There is one problem facing humanity that is now so urgent that, unless it is resolved in the next two decades, it will destroy our global civilisation: the climate crisis. It seems almost superfluous to say it, but the warming trend is real and accelerating, and it's our pollution that is responsible. All but the most ignorant and biased of sceptics now admit this truth, and it's underlined by the findings of the Intergovernmental Panel on Climate Change. This body of world experts is painfully conservative, for it works by consensus and includes government representatives from the United States, China and Saudi Arabia, all of whom must assent to every word of every finding. In its Fourth Assessment Report (published in November 2007), the IPCC blandly stated that the warming trend was "very likely" (more than 90 per cent certain) human-caused, and subsequent research has only confirmed this, dismissing the idea that sunspots or any other cause promoted by the sceptics could play a role.

The further into the climate system we try to follow the consequences, the less certain the link with human activity becomes, yet even here great advances are being made. In its Fourth Assessment Report, the IPCC thought it only "likely" (66-90 per cent certain) that there was a relationship between the human-caused warming and various changes in Earth's physical and biological systems. In May 2008, however, the largest and most definitive study yet on this subject was published in the world's leading science journal, Nature. It announced that a clear link existed between a huge number of changes in the natural world and human-caused warming. The researchers' database included such diverse observations as changes in polar bear behaviour, stream flow, timing of grape harvests, the flowering time of plants, and bird migration. This study represents a landmark in our understanding of just how profoundly we are influencing the very Earth processes that give us life.

As we seek to understand our increasing impact on our planet, it's helpful to think about the way we are shuffling matter among the three great organs of Gaia and thereby creating an imbalance. Gaia, the living planet Earth, is like a tree in that it is not alive all the way through. Instead, life is restricted to a thin "rind" extending a dozen or so kilometres below Earth's surface and around twenty-five kilometres above it. This rind is composed of three great organs: the Earth's crust, air and water. We must consider how matter flows through these three organs, how they interact, and how life in turn influences them, if we are to understand our planetary home.

Earth's crust may seem a passive organ--a mere substrate on which life exists--but it is deeply influenced by the presence of life. Today, the energy captured by plants through photosynthesis contributes three times more energy to Earth's overall geochemical cycles (the weathering, burial and formation of rocks) than geological activity such as mountain building and volcanism, and in the past this extra energy played an important role in forming the Earth we know. During its first 600 million years (before life arose), Earth had no continents. A remarkable recent study suggests that it was the extra energy captured by algal and bacterial life that led to the development of Earth's continental crust.

Earth's original crust was all basalt, and today basaltic crust underlies the oceans. Continental crust is formed by the weathering of basalt, which separates the lighter elements (particularly those that are silicarich) from the denser ones. It's these lighter elements, once they have been compressed and heated, that form granite and give rise to continental crust. The scientists postulate that the vast amount of basalt weathering required to form the continents could only have occurred if algal and bacterial life was capturing huge amounts of solar energy, some of which was used to manufacture chemicals, such as oxygen and acids, which helped to break down the rocks to form sediment. Although this finding is still debated, the inference is that without the contributions of early life to the geological cycle, there would never have been earth beneath our feet.

Earth's crust is dynamic, and its dynamism is particularly vital to life. The continents shift about on large "plates," so that every 300 million years or so the plates bearing the continents coalesce, creating an Earth with a single large continent surrounded by sea. Then the plates break apart again, only to come together in another cycle. No one understands precisely what makes Earth's plates move, but the force of gravity, circulation within the molten mantle of the Earth, and the pull of the Moon are all thought to exert an influence.

The most important thing about this movement of the plates--in relation to life, at least--is the effect it has on the recycling of minerals and salts. Where plates collide, the rock underlying one continent is thrust under another and is melted. As a result, mountain ranges and volcanoes are formed, and rivers erode the mineral-rich rocks, creating fresh new soil. It is this renewal, along with the slow grinding of glaciers, that fertilises life on Earth with the minerals that are essential to plant and animal growth.

Of all the minerals recycled through Earth's crust, carbon is the most critical for this discussion. On dead planets such as Mars and Venus, the great bulk of the atmosphere is made up of C[O.sub.2]. On our living planet, in contrast, C[O.sub.2] constitutes just a few parts per 10,000 of the atmosphere. The reason for the difference is that over the aeons, enormous quantities of carbon have been drawn into Earth's crust, where today they reside in the form of coal, oil, natural gas and limestone.

If the movement of the plates is important to life on land, it is absolutely vital to life in the sea. The waters of the ocean are recycled, by means of evaporation and precipitation, through Earth's rivers every 30,000 to 40,000 years, and with each recycling, rivers leach salt from the rocks, which is carried into the sea. You might deduce from this that the oceans are growing saltier. In the nineteenth century this is exactly what scientists thought. Assuming that the oceans were fresh upon formation, and knowing the rate at which salt was carried into the oceans by rivers, they estimated Earth to be just a few tens of millions of years old, and then coupled this incorrect finding with a belief that a sort of salty doomsday awaited us a few million years hence, when the oceans would have become as salty as the Dead Sea.

The truth is far more remarkable. Earth's oceans have maintained a relatively steady level of saltiness for billions of years, and they do so thanks to the mid-ocean ridges, which is where Earth's plates are pulled apart, allowing the ocean basins to grow. As the oceanic crust pulls apart, magma comes to the surface and the ocean penetrates this new, hot rock. Hydrothermal vents form, and through these eventually all of the ocean water in the world circulates. It takes 10 to 100 million years for all the water in the oceans to pass through the hydrothermal vents, but as it does so the chemical structure of the seawater is altered by the extreme heat, and salt is removed. It's this recycling of the oceans through evaporation, rainfall and rivers every 40,000 years, and through the movement of the crust at the mid-ocean ridges every 10 to 100 million years, that keeps the saltiness of the sea constant.

Earth is the water planet, and water, in its three states--vapour, liquid and solid--defines and sustains it. The principal part of its liquid state forms the second organ of Gaia: the oceans, which cover 71 per cent of Earth's surface. Solid water, mostly in the form of glacial ice, covers a further 10.4 per cent. Water is essential to life because the various electrochemical processes that constitute us and other life forms can only occur within it. The ocean was almost certainly the cradle of life, and it remains life's most expansive habitat. The volume of the oceans--1.37 billion cubic kilometres--is eleven times larger than all the land above the sea. But unlike the land, which is populated by life only at its surface, the entire volume of the oceans is capable of sustaining life.

The oceans are the most important means by which carbon is drawn from the atmosphere. Indeed, when considered on a time-scale of centuries, they are the only carbon sink that counts. And today, with more carbon in the air, these sinks have much more to absorb. Some of the carbon absorbed by the ocean is used by algae, and some remains dissolved in the water, where it forms carbonic acid. Some of the carbon taken in by algae falls to the ocean floor when the algae die and sink, and there it is destined to form carbonate rock, thereby removing the carbon more or less permanently from the atmosphere. The carbonic acid that remains in the water, however, is a very different matter. As it builds up, it causes the ocean to acidify, which damages life, including the algae that sequester the carbon. Ocean acidification is a much more urgent threat than we previously thought, and it is nowhere more advanced than in the north Pacific Ocean.

The north Pacific Ocean is so profligate of life that it seems like a fantasy land. When I first encountered it, walking the strand at Tofino, near Vancouver in British Columbia, I was awestruck by the drifts of mussel and oyster shells almost as long as my foot, the gigantic barnacles and other oversized sea wrack. Offshore, grey whales abounded within a few metres of the beach, as did seals and killer whales. For me, coming from a dry and impoverished land, the sheer abundance of life--and titanic life at that--was almost beyond my reckoning.

The unique productivity of the north Pacific is caused by the same factors that render it exquisitely vulnerable to acidification. The great frozen continent of Antarctica sits at the epicentre of Earth's oceanic system, for it is from its frozen margins that much of the deep and intermediate ocean water is exported. This icy origin dictates that the average temperature of the ocean is a mere 3.5 degrees Celsius, which is a good thing indeed for life, as frigid water is full of dissolved oxygen and so can support life in the oceans from bottom to top. There is, however, one important exception to this: the north Pacific, which, because of its unique configuration, is the only ocean not cooled and oxygenated by Antarctic waters.

Instead, deep water, depleted of oxygen and rich in C[O.sub.2] (and thus acid), wells up here, bringing with it the nutrients that feed the region's oversized life. The result is a fecund ocean, but one where the depth at which organisms can lay down calcareous skeletons is perilously close to the surface. In other oceans, living things can lay down skeletons to a depth of 1500-2600 metres, but in the north Pacific they cannot do so below 120-560 metres; thus, anything that requires a shell or skeleton has difficulty surviving at depth. This is why stony corals, which are found in every other ocean, are absent from the north Pacific. Increasing C[O.sub.2] in the atmosphere has already caused a rise of 30-100 metres in the boundary below which life cannot lay down a skeleton in the north Pacific. Scientists now warn that in just a few decades, creatures living in the far north Pacific may be unable to lay down skeletons even at the surface. This would mean an end to all those oysters, mussels, crabs and lobsters that this fecund ocean yields us. Indeed, ultimately it will probably mean an end to the whales and seabirds as well, for without krill, what will they feed upon? And in time, if the problem persists, all the world's oceans will suffer the same fate.

The atmosphere is the smallest, most vulnerable, yet most vital of Earth's organs. To look up into the blue vault of the heavens in an effort to judge its size or importance is profoundly misleading, for it appears as if the atmosphere stretches on endlessly. Yet the atmosphere is a gossamer-thin wrapping, insufficient even to swathe Earth's tallest peaks in breathable air. To gain a perspective on its actual size, we need to carry out a thought experiment. Imagine compressing the gases of the great aerial ocean of the atmosphere one thousandfold--until they become a liquid. Then imagine comparing the volume of liquid created with Earth's oceans. If you could do that, and could see the result, you would discover that the great aerial ocean is just one five-hundredth the size of Earth's liquid oceans. The size of a pollution sink is a prime indicator of its vulnerability. We all know that a small creek or lake is far more likely to be damaged by a given volume of pollution--say, sewage--than a large one. Because the oceans are 500 times larger than the atmosphere, their pollution history has been dramatically different. As we shall soon see, this simple fact will dominate human considerations in the twenty-first century--at least its first half.

It is our shuffling of matter between Gaia's three great organs--crust, air and water--that is at the heart of the climate-change problem. The problem results from digging up the dead--vast amounts of fossilised, once-living matter in the form of coal, oil and natural gas--and burning it. This liberates the ancient carbon that was once in living things, and allows it to reside again in the atmosphere and oceans. The carbon imbalance we have thus created is monumental: in just 200 years, the proportion of C[O.sub.2] in the atmosphere has risen by around 30 per cent--from 2.8 parts per 10,000 to 3.8 parts per 10,000 by 2008. Not for 55 million years has such an imbalance existed.

A NEW DARK AGE?

In 2006 James Lovelock published a book that bluntly laid before us the consequences of the carbon imbalance. The Revenge of Gaia was published in its author's eighty-seventh year, and it is as bleak and penetrating a perspective on human folly in regard to the environment as has ever been written. In it, Lovelock argues that Gaia's climate system is far more sensitive to greenhouse-gas pollution than we imagine, and that the system is already trapped in a vicious circle of positive feedback. "It is almost as if we had lit a fire to keep warm," Lovelock opines, "and failed to notice, as we piled on fuel, that the fire was out of control and the furniture had ignited." Although there is still time to avert a catastrophe, Lovelock believes that humans lack the foresight, wisdom and political energy required to do so. Instead, he predicts, before the twenty-first century is out our global civilisation will have collapsed and a new Dark Age will have dawned, wherein a few survivors (perhaps just one out of every ten alive today) will cling to the few remaining habitable regions, such as Greenland and the Antarctic Peninsula.

The events likely to destroy our civilisation include dramatic rises in sea level, which will flood coastal cities and some of the best agricultural land; changes in rainfall and extreme weather; and the disappearance of the glaciers that act as reservoirs of frozen water and whose melt supplies our most productive agricultural regions with water in the growing season. Yet it is the ensuing starvation, warfare and chaos that will be the greatest scourge, for in Lovelock's projected Dark Age the warlords will be armed with nuclear weapons.

How probable is it that this bleak vision will come to pass? New scientific data and technological analysis mean that in 2008 we are better placed than ever to determine the scale of the threat and its imminence. Let's begin with a new analysis of work done by the Intergovernmental Panel on Climate Change in 2001. In its Third Assessment Report, the IPCC published a series of projections concerning key indicators of Earth's climate system. These included estimates of how swiftly Earth's average temperatures might increase over the course of the twenty-first century, how much the oceans would rise, and how quickly C[O.sub.2] would accumulate in the atmosphere. The projections had an upper and lower limit, and they encompassed quite a wide range of possibilities. That concerning temperature, for example, indicated that the increase might be as little as 1.4 degrees Celsius, or as much as 5.8 degrees. From the perspective of human survival, the difference between 1.4 degrees and 5.8 is profound. Humanity can probably cope with a warming of less than 2 degrees, but a 5.8-degree warming would be truly catastrophic, heralding an ice-free world, and most likely human tragedy on the scale envisaged by Lovelock.

At the time these projections were published, climate sceptics lambasted them as unbelievable and grossly inflated, and widely proclaimed them in the popular press to be scientific scaremongering. By 2007, however, scientists had five to six years' worth of real-world data under their belts, allowing them to revisit the projections to determine their accuracy, at least over the near-term, early portion of the curve. What they discovered should have made the front page of every newspaper on the planet. Astonishingly, in every instance the real-world changes were right at the upper limit, or lay outside even the worst-case scenario presented by the IPCC. The full implications of these new studies have yet to sink in among those negotiating the global treaty that is supposed to protect humanity from dangerous climate change. They continue to argue on the basis of the old projections, which call for far less urgent action than what is actually required. Worse, the negotiations grind on as if we had an eternity to achieve outcomes. Lovelock, that seeming prophet of doom just two years ago, appears to have been right after all. Unless, that is, we can rouse ourselves to take immediate action.

Throughout the latter part of 2007 and into 2008, I found it increasingly hard to read the scientific findings on climate change without despairing. Perhaps the most dispiriting developments are occurring at the North Pole. The sea ice that covers the Arctic Ocean is an ancient feature of our planet. It has glistened brightly into space for at least 3 million years, and over that time a host of organisms, from plankton to walrus and narwal, have adapted to life on and under it. But its importance to Gaia is far greater than as a home for an unusual fauna, for the northern ice acts as a refrigerator that cools the entire planet. It does so by reflecting the sun's energy away from Earth. During the summer, the sun's rays beat down upon it twenty-four hours a day, but because the ice is bright, 90 per cent of that energy (which averages 240 watts per square metre) is deflected back into space. Where the ice is absent, however, the dark ocean is revealed, and it soaks up all of that solar energy and turns it into heat.

Around 1975, scientists noticed that the Arctic ice had begun to melt away. At first the rate was hardly worrying, and indeed many thought that it might just be part of a long-term cycle. But the trend continued, so that by 2005 the Arctic ice cap had been melting at a rate of around 8 per cent per decade for thirty years. At that rate, it would have taken until 2100 or thereabouts for the ice cap to disappear altogether, and that was a comfortably distant date for many. But then, in the summer of 2005, a dramatic change occurred. The rate of melt accelerated, so that around four times as much ice melted as compared with previous summers. As at the onset of the melting trend, scientists were hoping that this was a freak or cyclic event, and that in a subsequent summer the melting would once again slow. But the summer of 2006 saw almost as much ice lost as in 2005. Then, during the summer of 2007, the very worst loss of Arctic ice ever witnessed occurred.

These changes in the Arctic have left many scientists worried that the region is already in the grip of an irreversible transition. During the winter months, the Arctic is now warming four times faster than the global average, while the existing temperature increase year-round already exceeds 2 degrees Celsius. As a result, profound shifts are occurring in species distribution: some fish stocks in the Bering Sea, for example, have already moved by 800 kilometres. None of the models used to predict how the Arctic will change as it warms has been able to replicate any of these changes. None, indeed, is remotely accurate, meaning that as we try to predict the region's future, we are truly flying blind.

The extent of confusion is illustrated by a straw poll conducted among Arctic experts in March 2008. It asked whether they thought that this summer would see a regrowth of the Arctic ice. The winter had been a cold one, and the great loss of ice in the previous summer had been exceptional, leading the majority to say that a regrowth of the ice cap was likely. Yet by May 2008 the melting had begun once more, and the average daily loss of Arctic sea ice was, on average, 6000 square kilometres per week greater than for the same period in 2007. By June the losses had become so severe that one Norwegian expert was saying that 2008 could see the Arctic's first ice-free summer. We may or may not see an ice-free Arctic this year, but if this summer's melt follows the pattern of recent decades, by the time this essay is published, in September 2008, the Arctic ice cap will have lost almost half of its extent--going from 4.2 million to 2.2 million square kilometres--and an ice-free Arctic will be a mere handful of years away.

What will happen during that first iceless summer? Most likely, not much at all, for it will take several summers' worth of energy to warm the surface of the Arctic sea to a point where dangerous changes are generated further south. If recent history is anything to go by, during that first iceless summer the sceptics will say, "See, we told you that there was nothing to fear from an ice-free Arctic," and those who don't know any better will grasp at the reassurance. But each year thereafter, the ocean at the top of the world will warm inexorably, and the temperature gradient that controls climatic zones across the northern hemisphere will shift. It's difficult to know precisely how that will affect humanity, but if we look back to the last time in Earth history when such a great warming occurred--55 million years ago--we see an ominously different world. Back then, lemurs sported in the rainforests of Greenland, while the tropics were covered in a spiny, thin and alien-looking cover of vegetation, which is today entirely extinct. No one knows how quickly the world's climate altered back then, but one cannot help but fear what a similar scale of change might mean for humanity today.

So swift are the changes already occurring in the Arctic that much of the human response to the crisis is rendered hopelessly inadequate. The warming, for example, has accelerated the rate of melt of the Greenland ice cap, which is now melting away at between 250 and 300 cubic kilometres per year. Public policy responses and political discourse, meanwhile, are based on a previous rate of loss of just 50 cubic kilometres per year. And this melt really does have immediate relevance, for the Greenland ice cap sits on land and as it melts, it contributes to a rise in sea level. Even the most committed conservationists have been forced to rethink their strategy. Neil Hamilton, the director of the WWF International Arctic Programme, said in a talk in Canberra in May this year that, "We [the WWF] are no longer trying to protect the Arctic," because it is too late. He believes that the region's first ice-free summer may arrive before 2013, and admits to having no idea what the Arctic might look like in 2050.

New ramifications of rapid warming are continually being discovered. In 2006 scientists realised that the sea can die as a result of massive global warming. Indeed, it has done so several times during Earth's history, and when it does, it takes most life on land with it. Evidence of a dying sea comes from the sediments laid down on its floor. At different times enormous deposits of black shale have formed, and these are the source of much of Earth's oil. Oil, of course, is derived from living things, and it can only form when the organic matter that gives rise to it doesn't rot. Very little, if any, oil is forming in the oceans today because their depths are so filled with oxygen that living things can exist in the depths, and life in the abyss, as life always does, efficiently uses and recycles whatever organic matter rains down on it. It therefore takes a dead ocean--at least one whose depths are dead--to make oil, and oceans begin to die when the abyss is starved of oxygen.

The ocean circulation is vigorous today because the poles are cold and the equator warm. Most of the deep ocean water is sourced from around the Antarctic (which is why it is so cool, around 1-2 degrees Celsius), and it is this cold water (which can hold lots of oxygen) that permits life in the depths. The cold poles and warm equator also cause the winds that drive surface currents, and the resultant surface mixing that helps oxygenate the waters.

The most devastating example of oceanic death occurred around 250 million years ago, when 95 per cent of all life perished. Just what occurred then is only now beginning to be understood, largely because of a great breakthrough in geochemistry. It was realised that living things such as bacteria, which rarely leave conventional fossils, nevertheless leave a chemical signature of their existence in rocks. Geologists studying rocks in Western Australia that dated to the Permian-Triassic extinction of 250 million years ago discovered traces of the unique lipids (fatty molecules) made by strange kinds of bacteria known as purple bacteria and green sulphur bacteria. These bacteria only thrive in waters that are well lit by the sun, yet are low in oxygen and high in hydrogen sulphide. Such conditions exist only in very restricted and unusual environments today, such as the "jellyfish lakes" of Palau. Yet the story preserved in the rocks reveals that most if not all of Earth's oceans resembled this environment 250 million years ago.

The steps leading to the death of the oceans have been reconstructed as follows. First, a sudden increase of C[O.sub.2] and methane in the atmosphere causes rapid warming of air and sea, which disrupts ocean currents and warms the depths. Increased warming of the poles brings winds and surface currents to a near standstill; and because of slowed circulation, and the fact that warm water holds less oxygen than cold, the ocean depths become deprived of oxygen. In this environment, bacteria that don't require oxygen multiply, and they emit huge volumes of sulphur. Eventually, the sulphurous, oxygen-starved water builds until it reaches the sunlit zone, and then the green sulphur bacteria flourish, producing huge volumes of toxic hydrogen sulphide, which enters the atmosphere in great belched bubbles, destroying much life on land. Eventually the gas rises high into the atmosphere, where it destroys the ozone layer, and the increased UV radiation devastates what is left of life on Earth.

What does an Earth with a dead ocean look like? Peter Ward, a palae-ontologist and expert in his field, imagines it as follows:

   Look out on the surface of the great sea itself, and as far as the
   eye can see there is a mirrored flatness, an ocean without
   whitecaps. Yet that is not the biggest surprise. From shore to the
   horizon, there is but an unending purple colour--a vast, flat, oily
   purple, not looking at all like water ... The colour comes from a
   vast concentration of purple bacteria ... At last there is motion
   on the sea, yet it is not life, but anti-life. Not far from the
   fetid shore, a large bubble of gas belches from the viscous
   oil-slick-like surface ... it is hydrogen sulphide, produced by
   green sulphur bacteria growing amid their purple cousins. There is
   one final surprise. We look upward, to the sky. High, vastly high
   overhead, there are thin clouds, clouds existing far in excess of
   the highest clouds found on our Earth. They exist in a place that
   changes the very colour of the sky itself. We are under a pale
   green sky, and it has the smell of death and poison.

How much time, exactly, do we have to prove Lovelock wrong? On 31 March 2008, Dr James Hansen (who is arguably the world's leading climate scientist) and eight of his colleagues provided a new, alarming, though still partial, answer to this question. They looked back over the increasingly complete ice-core record, which documents the last three-quarters of a million years of Earth's climatic history, and tried to determine how much warming a given amount of atmospheric C[O.sub.2] pollution would produce, and how long it would take to produce it. Their most alarming discovery was that, when viewed over the long term, Earth's climate system is about twice as sensitive to C[O.sub.2] pollution as is shown on the IPCC's century-long projections. This implies that there is already enough greenhouse-gas pollution in the atmosphere to cause 2 degrees Celsius of warming, bringing about conditions not seen on Earth for 2-3 million years and constituting, according to the authors, "a degree of warming that would surely yield 'dangerous' climate impacts."

Fortunately for us, some, perhaps half, of that warming is currently masked by other pollutants, known collectively as the agents of global dimming, which reflect sunlight into space, thus cooling Earth. These include sulphur dioxide (the cause of acid rain), photochemical smog and tiny particles of carbon called aerosols. All of these pollutants are dangerous to human health, and it was for this reason in part that governments in Europe and the United States moved to regulate them long before they tackled the greenhouse gases. They are also very short-lived in the atmosphere, lasting only hours to weeks.

Today, China, India and other rapidly industrialising economies are releasing these agents of global dimming in ever-increasing quantities. Yet because of their effect on visibility and their serious impact on human health, there's good reason to believe that in the near future such nations will move to curb their release. Indeed, in the lead-up to the Beijing Olympics, heroic efforts were being made to do just that over large parts of north-eastern China. One particularly effective instrument used to achieve this is a government subsidy for every kilowatt of electricity generated at plants that do not emit sulphur dioxide. As a result of this scheme, one of China's "big three" electricity providers, Datang International, is already on track to have all of its generation plants fitted with sulphur-dioxide scrubbers by the end of 2009, and the competition is not far behind. If no attempt is made to reduce the agents of global warming concurrently with such clean-ups of the agents of global dimming, humanity stands to experience a near-instantaneous increase in warming that could have catastrophic consequences.

Hansen and his colleagues have arrived at a new understanding of how long it takes for the full warming consequences of a given amount of greenhouse gas to be felt. Two major factors cause a delay in the warming. Of these, the rate at which the oceans are able to absorb the extra heat trapped in the atmosphere is perhaps the most important, and certainly the most easily determined. According to Hansen, if the delay caused by the oceans alone is considered, then we could expect to feel a third of any warming caused by a given amount of greenhouse gas in the first few years after it is released. Three-quarters of the full warming effect would be felt within 250 years, and all of it within a millennium.

There is another factor that causes a delay in the warming impact: Earth's ice, which currently covers 10.4 per cent of the planet. You can think of ice as a kind of battery that stores cold, and the rate at which ice vanishes from a warming world is a key factor in determining when the full warming impact will be felt. Unfortunately, it is extremely difficult, if not impossible, to predict the decay of Earth's ice fields, because they don't simply melt away as an ice cube might if left on a bench; instead, large portions can collapse spectacularly, spilling into the sea in fragments, where they rapidly melt. Such phenomena cannot be replicated in any of the models used to predict climate change, which is a tragedy, for in the real world the polar and glacial ice caps are altering profoundly and rapidly.

The rapid surface melting of the Greenland ice cap, the collapse of coastal ice shelves that hold back glaciers, a marked speeding of the ice streams that flow through great ice shelves such as the West Antarctic Ice Sheet, and an alarming overall loss of ice are all being observed in the real world, yet we are at a loss to determine how quickly, or how much, they will add to a rising ocean. But one can reasonably speculate. As Hansen and his colleagues put it, "Sea-level changes of several metres per century occur in the palaeoclimate record, in response to forcings slower and weaker than the present human-made forcing." This indicates that the ice may disintegrate and melt faster than previously assumed, and that the warming may be delayed less by the ice than assumed.

In their landmark paper, Hansen and his colleagues make a useful distinction between climatic "tipping points" and "the point of no return." The climatic tipping point is the point at which the greenhouse-gas concentration reaches a level sufficient to cause catastrophic climate change. The point of no return is reached when that concentration of greenhouse gas has been in place sufficiently long to give rise to an irreversible process. Humanity is now suspended between a tipping point and a point of no return, and only the most strenuous efforts on our part are capable of returning us to safe ground. The work of Hansen and his colleagues indicates that we still have a few years before we reach the point of no return, but that there is not a second to waste. This is our greatest challenge, and the path forward involves a drastic change in energy use. It also means making full use of the tools we have at our disposal--and inventing new tools--to draw the pollution out of the air and save us from Lovelock's new Dark Age.

THE COAL CONUNDRUM

Hansen and his colleagues summarise the challenge as follows: "If humanity wishes to preserve a planet similar to that on which civilisation developed and to which life on Earth is adapted, palaeoclimate evidence and ongoing climate change suggest that C[O.sub.2] will need to be reduced from its current 385ppm [parts per million] to at most 350ppm." This, they argue, can only be achieved by phasing out all conventional coal burning by 2030, and by aggressively reducing the amount of C[O.sub.2] in the atmosphere by capturing it in growing tropical forests and in agricultural soils. That a rapid phase-out of coal is in itself not enough is elegantly illustrated by the fact that the concentration of C[O.sub.2] in the atmosphere would remain above 350ppm for 200 years were a coal phase-out to be achieved within the next decade or two, and nothing else done. Yet the point of no return is, in all probability, less than twenty to forty years away.

So just how large is the task of replacing the current fossil-fuel-based energy supply (in particular, conventional coal burning) with other, nonpolluting fuel sources? On 3 April 2008, the researchers Roger Pielke, Tom Wigley and Christopher Green published a study examining the IPCC projections that guide current thinking on the extent to which emissions need to be reduced. Shockingly, they discovered that the IPCC projections underestimate the scale of the task by two-thirds.

The reason for this is that the lion's share of the emissions reductions required in the future are already "built in" to the IPCC's scenarios. In other words, the IPCC assumes that these reductions will occur anyway, even in the absence of specific policies aimed at producing the shift. While such an assumption may seem remarkable, it was based on the observation that improvements in technologies--and in particular in their efficiency--occur over time. Thus internal combustion engines have become more efficient, as have refrigerators and countless electrical appliances. But can we expect that such efficiencies will lead to a slowing in the overall rate of greenhouse-gas pollution, regardless of government policy? The answer came when the researchers examined the relevant changes in the real world that had occurred over the first eight years of the twenty-first century. Dismayingly, they discovered that no "built-in" emissions reductions were occurring: in fact, exactly the reverse was happening, for the efficiency of global energy use (measured as energy intensity) and carbon intensity (pollution) have both risen over the period.

Clearly the task of combating the climate crisis is far larger than conventional wisdom assumes. In order to establish how much larger, the researchers ran the IPCC projections without assuming that "built-in" emissions reductions would occur. They found that the real task is four times larger than the IPCC projections indicate (and this was assuming that we wish to stabilise atmospheric C[O.sub.2] at 500 parts per million, rather than Hansen's 350!). In order to rise to this challenge, humanity will need to implement clean energy technologies around ten times faster than is projected by the most ambitious of the IPCC scenarios.

In summary, Pielke and his colleagues note soberly that, "The world is on a development and energy path that will bring with it a surge in carbon dioxide emissions--a surge that will only end with a transformation of global energy systems." Indeed, keeping the developing Chinese and Indian economies in mind, they believe that the real surge in C[O.sub.2] emissions, if a concerted effort is not made, is only at its beginning. This is not to say that humanity is bound to fail. Indeed, at moments of crisis, such as during the Second World War, astonishing breakthroughs in technology and manufacturing have occurred. The problem is that, so far, humanity has failed to see the need for urgency. A commentator on this groundbreaking research astutely pointed out where the real human deficit lay in all of this, saying that when it comes to dealing with the climate crisis, "no amount of scenario planning can replace the need for will and leadership."

So, how abundantly blessed are we with will and leadership? A look at the state of the coal industry and its much-vaunted clean coal initiatives (that is, technologies that lessen to some degree the pollution from coal-burning) is enough to drive one to despair. For years the US government and industry partners have funded the planning of a pioneering clean coal power plant known as FutureGen. The plant is designed to burn coal with great efficiency, to capture the resulting C[O.sub.2] and store it underground. If the technology proves economical, effective and safe, it will be a potent tool in our armoury for combating climate change.

The FutureGen project was meant to lead the charge towards clean coal, so many were delighted when, in December 2007, after seemingly interminable delays, a site for the plant was finally announced, in Mattoon, Illinois. But then, astonishingly, just a month later, on 29 January 2008, the US Department of Energy announced that it was withdrawing funding from the project! The reasons for this catastrophic decision remain obscure, but lawyers representing Illinois claim the real reason is that Texas lost the bid to host the plant, and this cost the project its political support.

The enormous growth in energy generation in China, most of which is coal-fired, adds to the urgency of the need for a clean coal solution. Power generation capacity is projected to rise from 442,000 megawatts in 2004 to 920,000 by 2010--a doubling in just seven years. That equates to the installation of around 1300 megawatts of power capacity each week, about the equivalent of a new Yallourn-sized power station!

It is obvious that enormous investment in electricity generation infrastructure will, whether we like it or not, dictate key elements of the world's climate response. China will not simply knock down its newly constructed power plants in response to the need for emission reductions. Instead, carbon capture will have to be retrofitted to these plants, and ways found to cover the costs. The bad news is that such retrofitting is even more economically and technologically challenging than building a FutureGen-like clean coal project from square one.

Just how the required technology will be developed, and such a huge retrofit financed, is far from clear. The challenge is all the more difficult because in China electricity prices are capped. Power companies cannot pass on rises in the cost of power generation to consumers; nor, given that recent increases in the price of coal are leading to financial losses, is it feasible for the companies to invest in the new technology themselves. Despite the effect on future investment, the central government is reluctant to raise electricity prices because inflation, driven by rising food prices, is already straining social harmony. The only feasible solution in such a case is for the developed world to help shoulder the cost burden of reducing the pollution.

One way of achieving that is to allow transfer of funds through a Clean Development Mechanism, such as the one available in the European trading scheme, which allows polluters in Europe to pay for emissions abatement in places such as China if that is more cost-effective than reducing pollution themselves. Unfortunately, there are strong signs that in a future carbon-trading scheme the US will allow no such transfers, believing they are tantamount to helping the opposition. More fundamentally, while carbon capture remains an unproven technology, no funds transfer can occur under any scheme. Therefore, there's an urgent need for someone to invest in the development of carbon capture technology.

With the fate of their industry dependent on investments in new technology, why, you might ask, are the coal companies waiting for government agencies (such as the US Department of Energy) to foot the bill for clean coal? After all, the price of thermal coal--the kind used in power plants--is expected to double this year to around US $112 per tonne (from its early 2008 cost of $56 per tonne). Coking coal (which is used in steel-making) is doing even better, for it will bring US$ 300 per tonne, up from $97 a year before. With such windfall profits accruing to the industry, there's plenty of latitude for investment in technologies that promise to secure its future. Thus far, investments by coal companies in clean coal technologies have been insufficient even to fund a single large-scale demonstration plant. It seems that leadership, vision and will are more sadly lacking in this industry than in government.

Of course, there are reasons for this. Coalmines and coal-fired power plants often have different owners, so while the mines are making a profit, the power generators might be feeling the squeeze. Yet they are ultimately interdependent and you'd think that the coal industry's peak body would be busying itself to find a solution. In fact, nothing effective is happening, and it's clear that government must take on the responsibility. In its 2008 budget the Rudd government promised $500 million of taxpayers' money to develop clean coal technology. This is just not enough. Coal exports are said to be worth $23 billion annually to Australia's economy. If a surcharge of just 10 per cent was placed on such exports (and who would consider that unreasonable in light of the GST we all pay?), a war-chest of $12 billion could be built up in only five years. If clean coal is to become a reality in time to combat the climate crisis, this is the sort of money that's required, and it's morally right that the coal companies, rather than the Australian public, should pay it. Following this, Australia could pool its funds with reliable partners such as the German utility RWE, whose 450-megawatt power plant is scheduled for commissioning in 2014, to really speed progress towards a clean coal solution.

One other aspect of clean coal technology is worth touching on: the reliance on appropriate geological structures to store C[O.sub.2] underground. Where such structures exist near coal-fired power plants, the cost of clean coal will be much reduced. If, however, we envisage replacing every conventional coal-fired plant on Earth with clean coal, things look very different, for the amount of pipeline infrastructure required to do this is staggeringly large. Indeed, it probably rivals the entire existing pipeline infrastructure deployed by the oil and gas industries combined. With pipeline costs going through the roof (partly as a result of demand in China), it is not feasible that the required pipelines will be in place by 2030. Of course, this kind of argument could be applied to any energy technology that requires rapid ramping up, as all face severe bottlenecks of one sort or another. I merely note it here to make the point that clean coal technologies can never be a complete, worldwide replacement for existing coal facilities. Globally, renewable energy will have to take a significant portion of conventional coal's market share.

Do not assume from any of this that I believe clean coal technologies to be safe or cost-effective. In some circumstances they may prove to be as dangerous as nuclear power and as expensive as solar panels. My point is that the world, and China in particular, has gone so far down the road of using coal as an energy source that we have little choice but to pursue a solution that involves it.