How long will it take the Earth to cool sufficiently if we achieve zero greenhouse-gas emissions and start reducing atmospheric carbon dioxide? This will depend, in part, on how long it takes us to make the major economic change necessary to achieve zero emissions and to put in place a system to capture and sequester excess carbon dioxide from the atmosphere. Historical precedents for rapid industrial change, such as the Asian 'tiger economies' and the information-technology revolution, suggest that it could be achieved in two to three decades. The economic restructuring achieved during World War II shows that a fast economic transition like this is possible.

However, even after major economic changes were made, drawing down excess carbon dioxide from the air could take 50 to 100 years (even at a high depletion-rate of 6 billion tonnes a year), because of the carbon still being emitted, and the time necessary to develop, build, and maintain such large-scale processes.

While Arctic cooling would start before all the excess carbon dioxide was taken out of the air, it could still be a century before it returned to a safe-climate condition. Over that lengthy amount of time, the Earth would still be subject to rising temperatures. A 1-to-2-degree rise above the present temperature is not out of the question, even if we established a zero-emissions economy in two to three decades - especially when the aerosol dilemma is taken into account.

The risk is real that during the early decades of the transition, major damage could be done to Earth's ecosystems, such as tropical rainforests. It is also possible that the permafrost, and other sources of natural carbon, could be so strongly mobilised, and the natural carbon sinks so damaged, that the process of taking carbon dioxide out of the air would be overwhelmed. In one century, enough ice could be lost from the Greenland and West Antarctic ice-sheets to raise sea levels by several metres. If most of the ice in the Himalayas were lost, food production in nations from the Indian sub-continent to China would be drastically reduced. These would be civilisation-disrupting changes, even if run-on heating was avoided.

The grim reality is that the Earth is too hot right now. Even a zero-emissions strategy and a monumental effort to pull excess carbon dioxide out of the atmosphere will not achieve the necessary cooling soon enough. We must consider the third strategy - cooling the Earth directly.

Natural ecosystems play a role in moderating the Earth's temperature. Marine plankton releases a gas, dimethyl sulphide, that disperses into the air and helps to form dense, sunlight-reflecting cloud; there is also some evidence that water evaporating from forests carries bacteria into the atmosphere to aid the formation of light-reflecting clouds. So boosting the health of marine plankton could help, as could re-establishing forests on a large scale; however, as global warming grips the planet, it is becoming more difficult to maintain biological systems, let alone to re-establish large areas of forest. If they are to cool the atmosphere, the Earth's ecosystems may need even more help.

In 1992, a US National Academy of Science report on greenhouse warming discussed climate geo-engineering, including very large-scale projects that would deflect a small proportion of the solar radiation striking the upper atmosphere, in order to produce a small cooling. The possibilities considered ranged from the science-fiction-like placement of reflectors in s.p.a.ce, to copying the cooling effect of volcanic eruptions by pumping sulphates, or other particles, into the upper atmosphere, where they would last for a year or two.

More recently, scientists such as Ken Caldeira and n.o.bel-laureate Paul Crutzen have studied proposals to pump sulphate aerosols into the stratosphere, and it seems that this measure could fully cancel the warming caused by greenhouse gases and other warming agents, such as black soot. The sulphate program could be implemented within a few years and have an immediate cooling effect. However, it is not a subst.i.tute for a zero-emissions program, or an excuse to continue emitting greenhouse gas. Nor is it a safe solution in the long-term, since any premature end, or interruption, to such a program - through war or economic recession, for example - would subject the globe to a major heating-pulse within two years.

The greatest value from a sulphate geo-engineering program, with the least ecological risk, would be to carry it out as soon as possible, for as short a time as possible. Every effort should be made to reduce the necessary intensity of any geo-engineering program - for example, by bringing down methane and black-soot pollution as fast as possible.

Humans have been unintentionally geo-engineering the Earth for a long time. The first major intervention was the use of fire to reshape ecosystems over large areas; the second was the introduction of large-scale land clearing for farming and other purposes; and the most recent has been industrialisation, which moved ma.s.sive amounts of materials into the air, the waters, and the land. The warming effects of this pollution are now, belatedly, recognised as very dangerous; but it looks as though simply stopping this geo-engineering, without first returning the Earth to a viable state, is not a workable option.

It is critical that temporary atmospheric geo-engineering should complement, rather than replace, a zero-emissions industrial structure that would remove the full excess carbon dioxide from the air as fast as possible. If it is not part of such a package, atmospheric geo-engineering should be rejected outright.

If this kind of program seems desperate, it is only an indication of the desperate straits our planet is now in. We must consider the least-worst options to save the Earth. These are absolutely necessary to stop the climate becoming so warm that a return to the safe zone is beyond reach.

CHAPTER 14.

Putting the Plan Together.

This book started in the Arctic, because shrinking sea-ice is one of the triggers which shows us that climate change is already dangerous. To recover the Arctic's climate, the goal developed in Chapter 13 is to replace global warming with global cooling sufficient to drop the temperature enough to allow the full return of the summer sea-ice. This is the only way we can avoid the domino effect of sea-ice loss, the albedo flip, a warmer Arctic, a disintegrating Greenland ice sheet, more melting permafrost, and the whole catastrophe.

If we fail to stop global warming, life in the future will be h.e.l.lish - not because of what we will do from now on, but because of we have already done. Based on a conservative view of climate sensitivity: * Human emissions, so far, have produced a global warming of 0.8 degrees.

* Our non-carbon dioxide greenhouse-gas emissions are adding about another 0.7 degrees to potential global warming. This amount of heating is offset by aerosols, which have a temporary cooling effect of approximately 0.51 degree, although this figure may well be too low.

* There is more warming to come as a result of 'thermal inertia', which refers to the delayed temperature effects produced by rising carbon dioxide levels. Only about half of the temperature increases will appear within 25 years, another quarter will take 150 years, and the last quarter may take many centuries to show up. This is because the oceans are continuing to absorb much of the heat acc.u.mulated as a result of rising carbon dioxide levels. Once the oceans cannot absorb any more, the heat will build up in the atmosphere. Thermal inertia and other lags in the system will take the total long-term global warming induced by human emissions, so far, to 1.4 degrees (although some warming will take a very long time to manifest, and will be affected by the extent to which the carbon cycle, over time, draws down the atmospheric concentration).

* The loss of the Arctic ice would also produce an increase of approximately 0.3 degrees, due to the albedo flip, although it will take time for this to happen.

* If total human emissions continue at their present level for two more decades, this is likely to add at least 0.5 degrees to the system by 2030; however, on current trends, emissions are projected to increase 60 per cent above present levels by 2030.

If we keep acting as we have, the Earth's atmospheric temperature will very likely be at least 2 degrees warmer by mid-century, with more warming to come.

A world free of the imminent threat of climate catastrophe would be one in which the Arctic basin again gleams white with sea-ice, and in which human ingenuity and determination is sufficient to cool the Earth back to the safe-climate zone. Although some people are incredulous when they first hear this proposition, we are yet to see a reputable climate researcher state that the Arctic could remain free of sea-ice long term without dangerous climate change occurring.

We can cool the planet, get back the Arctic sea-ice, and preserve the great polar and high-mountain ice-sheets - or watch the system spin out of control. There is no middle way between these stark options. It is not a matter of how much more greenhouse gas we can add to the atmosphere; it is a matter of what means we must use, what speed we must attain, and what extent we must reach, as we take action to draw down the current levels of greenhouse gases to a safe level, in time to avoid catastrophic climate change.

Any proposal for a goal of higher than 0.5 degrees warming would be foolhardy. The only alternative conclusion (which we do not support) is that it is safe to leave the Arctic sea-ice melted, and to plan for a long-term target much higher than the current warming of 0.8 degrees, on the a.s.sumption that such a course of action would not involve the planet crossing dangerous climate tipping points.

This second approach is, implicitly, the view of all the major nations and players involved in setting climate policy. Their challenge is to provide a reasoned argument explaining why it is a safe course of action to leave the Arctic Ocean free of ice in summer. We are not aware of any evidence that would support such a proposition.

NASA's James Hansen told scientists and others at the American Geophysical Union conference in San Francisco in December 2007 that we, as a species, pa.s.sed climate tipping points for major ice-sheet and species loss when we exceeded 300350 parts per million carbon dioxide in the atmosphere. He said that this point was pa.s.sed decades ago, and that climate zones such as the tropics, and temperate regions, will continue to shift, and the oceans will become more acidic, endangering much marine life. He added: 'We either begin to roll back not only the emissions [of carbon dioxide] but also the absolute amount in the atmosphere, or else we're going to get big impacts ... We should set a target of carbon dioxide that's low enough to avoid the point of no return [our emphasis].' Hansen estimated that target to be 300350 parts per million carbon dioxide, concluding: 'We have to figure out how to live without fossil fuels someday. Why not sooner?'

To restore the Arctic sea-ice, James Hansen and his coauthors have explicitly identified the target as being in the range of 300325 parts per million carbon dioxide. This is consistent with work by Hansen, before the Arctic summer of 2007, which pointed to the need for a cap that was a safe amount less than 1.7 degrees: Earth's positive energy imbalance is now continuous, relentless and growing ... this warming has brought us to the precipice of a great 'tipping point'. If we go over the edge, it will be a transition to 'a different planet', an environment far outside the range that has been experienced by humanity. There will be no return within the lifetime of any generation that can be imagined, and the trip will exterminate a large fraction of species on the planet.

More recently, in court testimony in Iowa, Hansen reaffirmed his view: 'I am not recommending that the world should aim for additional global warming of one degree. Indeed, because of potential sea level rise, as well as the other critical metrics ... I infer that it is desirable to avoid any further global warming [our emphasis].'

Global equity.

Until recently, most players in the climate-policy arena a.s.sumed that while global-warming emissions needed to be cut substantially, they did not need to be reduced to zero, so it would be fair for all people across the globe to share a reduced annual greenhouse-gas limit. Poor people could keep increasing their fossil-fuel use until their emissions reached the limit, and people in rich countries would need to keep reducing their emissions until they reached the same per capita level (a principle known as 'contraction and convergence').

But it is now clear that greenhouse-gas emissions must be cut to zero, levels of carbon dioxide must be drawn down and, most likely for some decades, the planet must be actively cooled. What, then, is a fair way to share these global tasks?

Our proposed safe-climate strategy is based on the protection of 'all people, all species, all generations'; but people and nations have contributed very unevenly to global warming. The developed economies are responsible for most of the historic atmospheric carbon emissions (and most emissions since 1990), and they have the responsibility and the capacity to provide resources to the world's poorer nations to create a path to development that preserves a safe climate. In a September 2007 report, the global investment bank Lehman Brothers called for a 'global warming superfund', and strongly implied that nations should pay into it on the basis of their historical emissions.

More systematically, a Greenhouse Development Rights framework has been designed by the US-based climate think-tank EcoEquity to support an emergency climate-stabilisation program while, at the same time, preserving the right of all people to reach a dignified level of sustainable human development that is free of the privations of poverty. The framework quantifies national responsibility and national capacity. Its goal is to provide a coherent, principle-based way of thinking about the national obligations to pay for emissions-reduction, and to adapt to changing climates.

There is no significant benefit to any country in continuing with a high-emissions economy, and all new investments should fit the modern zero-emissions paradigm. But what about cutting emissions from existing plant and equipment? The cost of this task, and of providing an adequate and secure energy-supply for all people in all countries, should be borne on the basis of past responsibility and present capacity.

There is no country, or cla.s.s of people, rich or poor, that will benefit in any durable way from a greenhouse-devastated world. All people, in every country, face the need for change. There is no doubt, however, that the lion's share of the problem was caused by the rich countries and cla.s.ses - initially unknowingly, but for at least the last two decades, wilfully - and so ethical equity principles would lay the bulk of the cost at their feet.

The challenge.

In light of the strong goals we have proposed - the need to develop large-scale drawdowns of carbon dioxide, and the need to solve the aerosols dilemma through geo-engineering or other means - there is a legitimate concern about whether, in present social and political circ.u.mstances, such deep and rapid change is possible. Very large levels of investment would be required to solve problems, develop and implement new technologies and solutions, and restructure the economy rapidly. It is hard to imagine that the unity of purpose required for such a transition could be attained in normal political and social circ.u.mstances.

Fortunately, human societies have another mode that they turn to in times of great need: the state of emergency. The form of emergency required to tackle the climate crisis will be different, in important ways, from more familiar emergencies: it will require coordinated global actions, it will be a long emergency, and the world will be very different, in many ways, when it is over.

It is possible that governments will grasp the gravity of our situation, recognise the emergency, and create the social, administrative, and economic circ.u.mstances required to deal with the climate crisis. More likely, we will need to create a popular movement and a deliberate advocacy program to create the necessary political will. Failure to declare a state of emergency is likely to result in a profoundly ineffective response to the climate crisis.

The risk today is that we continue to treat the climate crisis as something that lies in the future, and we continue to talk about reaching climate targets only years, or even decades, hence. So far, when practical difficulties arise with targets, we have re-calibrated the future, deluding ourselves that more warming is reasonable. It is not. Will we continue to recalibrate the future as the truth of climate change becomes increasingly inconvenient? That path will condemn our descendants to accept the bitter truth that we allowed two degrees of warming to become three, and then four, as the seas engulfed their cities and farmlands.

The alternative is to move beyond politics and business as usual, and into emergency mode.

PART THREE.

The Climate.

Emergency.

'The era of procrastination, of half-measures, of soothing and baffling expedients, of delays, is coming to a close. In its place we are entering a period of consequences.'

Winston Churchill, November 1936.

CHAPTER 15.

This Is An Emergency.

On 13 April 1970, some 321,000 kilometres from Earth, the Apollo 13 s.p.a.cecraft was. .h.i.t by an explosion that resulted in a loss of oxygen, potable water, and most electrical power. The access panel covering the oxygen tanks and fuel cells, which extended the entire length of the main craft's body, had been blown off. Apollo commander Jim Lovell's laconic message, 'Houston, we have a problem,' signalled a technological failure so great that mission objectives were abandoned. The moon landing was aborted.

The priority of the astronauts...o...b..ard the craft was survival at any cost. Life-support systems were at risk, and energy use had to be cut to a minimum, since little power was available. The crew shifted to their tiny lunar module - an emergency procedure than had been simulated during training - and abandoned the main craft, to which the module remained attached. But the lunar module was equipped only to sustain two people for two days; now, with insufficient capacity to keep the air clean or to heat the module to a habitable temperature, it needed to sustain three people for four days. There was no precedent, no manual, and no set of pre-tested solutions; but there was a driving imperative that was reinforced by mission control in Houston: 'Failure is not an option!'

A sequestration filter was invented on the run while carbon dioxide rose to dangerous levels. With inadequate mechanical control, the astronauts had to negotiate course alterations while engineers on the ground calculated the best way to use auxiliary motors to position the craft for the return journey.

Under this level of pressure, the on-the-run problem-solving required ingenuity and intense teamwork. The outcome was in doubt up to the last moment, but the crew made it and survived. The mission was deemed 'a successful failure'. Careful planning and training (including allowing for the possibility of having to jettison the main craft), strong cooperation between all involved, creative off-the-wall solutions, and a great measure of good fortune had combined to save the day.

Today, Earth faces a similar degree of peril, and its message can only be: 'People of the world, we have a problem.' Our planet's health and its capacity to function for the journey through time are now deeply imperilled. We stand on the brink of climate catastrophe.

Like Apollo 13, we have only one option: to abandon our life-as-normal project, hit the emergency b.u.t.ton, and plan with all our ingenuity how to survive and build a path for a return to a safe-climate Earth. We have to act with great speed, determination, and ingenuity. Our life-support systems - food, water, and stable temperatures - are at risk, and our consumption of fossil fuels is unsustainable. Energy use must be cut. The voyage will be perilous, and will require intense and innovative teamwork to find and mobilise technological and social answers to as-yet-unidentified problems. Putting aside mantras about high costs, our collective actions need to be driven, instead, by the imperative: 'Failure is not an option!' If we do not succeed, we will lose most of the life on this planet.

Lacking its main motors and with uncertain technological control functions, Apollo 13 had only one chance to position itself in exactly the right trajectory so that the moon's gravitational force would pull it back to Earth safely. We, too, have only one chance to get global warming under control and to guide the planet back to the safe-climate zone. If we do the wrong things, or we set our approach incorrectly and don't do enough, there will be no time for a second chance.

We have already entered an era of dangerous climate change. If left unchecked, the dynamics and inertia of our social and economic systems will sweep us on to ever more dangerous change and then, most likely within a decade, to an era of catastrophic climate change.

If the response to global warming continues to be contained within the current all-too-narrow parameters, it will guarantee disaster. Given the lessons from the Arctic summer of 2007 - let alone all the other early-earning signs that climate scientists are noting increasingly- allowing warming to reach even 2 degrees, let alone the increasingly advocated 3 degrees, is reckless.

This is our emergency.

CHAPTER 16.

A Systemic Breakdown.

The Apollo 13 emergency put just three lives at risk. Large emergencies triggered by flood, fire, famine, earthquake, or disease may affect millions. Across such diverse circ.u.mstances, the usual approach is to direct all available resources towards resolving the immediate crisis and to relegate non-essential concerns to the back burner.

Today, there is a practical argument that we should focus all our attention exclusively on the climate crisis, because it will take a huge effort to solve; but we need to ask whether there are other issues that will be seen, in retrospect, to have caused major problems if they were to be ignored, either because they are of great moral significance or because they seem more compelling in the short term.

The unambiguous answer is that there are several key concerns that must be resolved together with the climate crisis. There are those - such as peak oil, severe economic downturn, warfare, and pandemics - that cannot be ignored because their impacts on all people are so great. There are also ethical problems we should not ignore, such as poverty (including the adequacy of food supply at an affordable price) and the need for biodiversity protection.

The intertwined problem of climate and dwindling oil reserves is a good example. The continuing discovery of geological reserves of cheap conventional oil cannot keep pace with growing world demand, and the crisis point for oil production and consumption, commonly referred to as 'peak oil', is a reality. Its emergence is reflected, in part, in rising oil prices and in the expectation that they will continue to increase as the gap between supply and demand increases in coming years. In Australia, the 2007 Queensland state government's task-force report Queensland's Vulnerability to Rising Oil Prices found 'overwhelming evidence' that world oil production would reach an absolute peak in the next ten years; at the same time, the US Department of Energy predicts that demand for this declining resource will have increased by 24 per cent by 2020.

Clearly, we cannot resolve the global-warming threat before peak oil demands our attention in a very practical way. Nor can we delay resolving the climate issue: the restructuring needed to solve the peak-oil problem will take at least ten to 20 years, yet the climate solution demands major economic changes in the same time-period. The two problems must be considered together with integrated solutions.

At the same time, we must find appropriate solutions that also address other challenges. To achieve a safe climate and eliminate human greenhouse-gas emissions, we need to apply many resources simultaneously; we need to take large amounts of excess carbon dioxide out of the air, and we need to actively cool the Earth; at the same time, we need to maintain adequate supplies of affordable food, and secure survival of the world's biodiversity.

The production of fuel subst.i.tutes as a solution to peak oil is an example of the sort of challenge we are encountering in trying to achieve integrated solutions. Faced with increasing dependence on imported oil (which is continually rising in price), the US government, among others, is actively encouraging the diversion of food crops to the production of ethanol, a petrol subst.i.tute. Together with climate-related food-production problems, the ethanol 'solution' has contributed to global food shortages and sharply rising prices, and has particularly affected the poor and malnourished.

For transport, the alternative to focusing on the replacement of one organic fuel source (petrol) with another (ethanol) is to actively reduce the demand for energy - for example, by replacing current cars with vehicles designed for ultra-efficiency (such as electric vehicles charged from renewable sources), or by creating infrastructure that enables people to switch from car travel to public transport, walking, or cycling. The need for mobility could also be reduced by improving urban planning, or by making use of electronic 'virtual travel' such as video-conferencing. So far, these demand-reduction strategies have not been given political prominence.

The connection between climate, rising oil and food prices, the financial crisis, and economic recession is another example of the interplay between critical issues. Since the 1987 Wall Street crash, monetary authorities have used credit expansion - and condoned the development of a whole new range of dubious financial services and practices - as a tool to promote consumption and to stop the economy spiralling into recession. But now strong inflationary pressures are being driven by rising oil and food prices, and by expansionary war expenditure for Iraq and Afghanistan - itself motivated in part by oil - and these are being financed by large deficits. The consequence has been financial crisis, but monetary authorities are now not as free to use credit expansion to increase demand, and this slowdown may have its own negative impacts on climate: if a recession is allowed to run its course, there could be less money available to invest in responses to the climate and peak-oil crises. On the other hand, if governments invest in traditional public infrastructure areas in order to 'prime the economic pump', the result may be more roads and freeways, which will exacerbate climate and peak-oil problems. Only if pump-priming investment is framed with the climate and peak-oil problems in mind will the response to recession produce a beneficial cycle of change.

A systemic crisis often arises when many problems come to bear on one key issue. In the late 1960s and early 1970s, there was concern about the likelihood of future large-scale food shortages, because population was growing rapidly and there was a fear that food production would fail to keep pace. Overall, populations did not continue to grow as fast as expected, and food supply expanded more rapidly - a result of the 'green revolution', which utilised new strains of higher-yield crops and increased inputs of water and fertiliser. This worked in the short term, but required more water per unit of agricultural output, and increased the use of nitrogen-based fertilisers, which release global-warming nitrogen oxides.

Now, a whole series of problems are driving a wedge between potential demand and actual supply for water. In many areas, and especially in the heavily populated developing countries of Asia, extra water was made available through tube wells, or bores. This worked for decades, but groundwater stocks are now running out, and in some places the water is naturally contaminated with a.r.s.enic, causing serious health problems. Global warming has also affected rainfall, so that there is less usable water available at the same time as urban demand for water is increasing.

An increase in unpredictable weather events and changing climates - for example, unusual monsoon patterns - are making it harder to maintain food supplies. Most available high-value land with agricultural potential has been utilised, so there is, increasingly, less opportunity to expand agricultural areas and to replace land that has been damaged by erosion and salinity. The UN's 2007 report Global Environment Outlook: environment for development found that total arable land has reached a plateau at 14 million square kilometres, while the area under cereal crops dropped from 7.2 to 6.6 million square kilometres between 1982 and 2002.

The continuing growth of the global population - and of incomes for many people in industrialising countries - is increasing demand for food, just as food crops are being diverted to biofuel production. As a result, the prices of many food staples have been rising sharply. Between 1974 and 2005, world food prices fell by three-quarters, in real terms. Since then, that trend has reversed, with the price of wheat almost doubling in 2007, and the prices of maize, milk, and oilseeds reaching near-record highs. In 2007, the food-price index, published by The Economist, increased by 75 per cent.

It seems that the price of food - or the supply of affordable food - is becoming a key indicator of a new phenomenon: a multi-issue crisis of sustainability that incorporates food, water, peak oil, and global warming.

At the same time, the natural physical infrastructure on which all living things depend is being put under more and more stress. Marine ecosystems are increasingly breaking down due to over-fishing, while forests in many parts of the world are being cleared on a vast scale. Where they're not fully cleared, forests often are being broken up into isolated islands that have a greater chance of being invaded by pest species and less capacity for native species to move between areas in response to fire and drought.

An overwhelming case has been put forward which says that we should not focus on climate change exclusively. If we ignore the many issues that could undermine life and wellbeing, we may, if we are lucky, solve the climate crisis only to find we have crashed the planet's life-support systems in some other way.

Since the beginning of the industrial revolution, we have failed to build and maintain a system that has enabled modern society to ensure its own sustainability and that of other living species. Now, we have a sustainability crisis with a mult.i.tude of serious symptoms. An effective governance system would antic.i.p.ate and prevent threats to sustainability, and would also have the capacity to restore the Earth and society to its safe zone as soon as possible.

CHAPTER 17.

When 'Reasonable' Is Not Enough.

In November 2007, UN secretary-general Ban Ki-Moon told the world that global warming is an emergency, and 'for emergency situations we need emergency action'. Why, then, has climate politics moved in such a painfully slow manner? How can the impa.s.se be resolved between urgent action, based on the science, and action that seems 'reasonable' in the current political environment?