Global Warming and Science Fiction
© Anthony G Williams
This is an occasionally revised compilation of three articles previously posted on my SFF blog
Last revised 8 July 2009
Global warming is an issue which is not going to go away, and that has implications for anyone writing fiction set in the foreseeable future. Any SF novel set within the next century or few which ignores this issue and its probable consequences will be likely to have a very short shelf-life before being seen as increasingly irrelevant. That doesn't mean that every such story should be about global warming, but that it should be set against a background which includes it – or the measures which were used to overcome it. This article is intended as a resource for SF writers and as a source of information to anyone interested in this subject. It will be kept under review and updated as appropriate.
I don't, in this article, intend to rehearse the well-known basic arguments around whether or not global warming is happening, and to what extent human activities are responsible. I should emphasise that I am not a climate scientist, nor do I have the access to supercomputers or the expertise to run my own climate models to reach my own conclusions; I'm just an interested observer. I accept what the vast majority of climate scientists are saying: that the Earth is warming up, that human activities are playing a major role in this and that the consequences are likely to be very serious if no effective counter-action is taken.
Anyone who isn't yet convinced that this is happening can read a wide variety of authoritative material on the web, such as the report of the US National Academies: Understanding and Responding to Climate Change; the Royal Society's Facts & Fictions about Climate Change; or, if you want the official 2007 report of the International Panel on Climate Change (the largest and most authoritative body studying this subject) go to the IPCC website. A more user-friendly summary can be found on Wikipedia, while I particularly recommend the New Scientist magazine's Climate Change: a guide for the Perplexed, since that tackles the issues by examining the common objections from climate change sceptics. Those with a scientific background who want to keep up with published research can follow Bob Tisdale's blog.
Instead, I want to focus on what might happen, and what might be done about it – subjects which provide very wide scope for science-fictional speculation. A conference of climate scientists in Copenhagen held in March 2009 attracted some 2,500 delegates and heard 600 presentations over the three days. Key findings include:
Recent observations confirm that, given high rates of observed emissions, the worst-case IPCC scenario trajectories (or even worse) are being realised.
societies are highly vulnerable to even modest levels of climate change, with poor nations and communities particularly at risk.
Rapid, sustained, and effective mitigation based on coordinated global and regional action is required to avoid "dangerous climate change" regardless of how it is defined.
This message was reinforced in May 2009, by a report from the Global Humanitarian Forum on the human costs already occurring as a result of climate change, arguing that 300 million people are already seriously affected, with 300,000 dying each year, as a consequence of the environmental degradation caused by climate change.
Over the past few years, the acceleration in climate change has been dramatically illustrated by the rapid shrinkage of summer ice cover over the Arctic Ocean.
All of this should be no great surprise. The rapid industrialisation of China (with a new coal-fired power station reportedly being built every week over the past few years) combined with the fact that very few countries have slowed down the increase in their CO2 output, was until recently boosting the rate of increase in atmospheric CO2 levels over that predicted by the IPCC. For all of its other unhappy consequences, the current economic recession should at least slow down the rate of change and provide a bit of a breathing space to get our environmental act together.
Despite this general view that conditions are changing quickly and that this will result in serious consequences for the global environment and for humanity, there is still much uncertainty over what precisely is going to happen. This is partly because no-one is certain of the exact link between the rate of increase in CO2 production and the rate and ultimate level of the global temperature increase; and similarly no-one knows the exact implications, for climate patterns across the world, of any specific increase in average temperature. This leaves scope for some imagination on the part of SF writers.
Perhaps the greatest uncertainty – and cause for worry – is over the issues of feedback and tipping points. Feedback concerns the threat that some consequences of increased temperature will themselves increase the rate of increase. One obvious example concerns the accelerating shrinkage in polar sea ice. The ice reflects 90 percent of the sun's rays and thus keeps temperatures down. As this disappears, more of the sea is exposed and this absorbs over 90 percent of the solar heat, which helps to explain why the Arctic is warming up faster than the rest of the world. Another example is the existence of large quantities of frozen methane in the ground within Arctic regions. As the ground warms up large quantities are already being released into the atmosphere – and methane is itself a greenhouse gas. This could all result in a tipping point, when the self-reinforcing changes gather such momentum that they rapidly accelerate beyond recovery. Nothing like as rapidly as shown in the ludicrous film The Day After Tomorrow, in which temperatures plummet drastically in a matter of minutes, but significant change could happen over a period of decades rather than centuries.
The expected consequences of climate change can be grouped under several broad headings: weather fluctuations; temperature and rainfall patterns; sea level changes; and ocean acidification.
Weather fluctuations, temperature and rainfall patterns
The weather fluctuations we can already see happening are the result of increased atmospheric instability as the temperature rises. While it isn't possible to attribute any particular extreme event to global warming (extreme weather has always occurred), it does mean that we are likely to see more, and more violent, storms. It also means that we are likely to see annual temperature and rainfall records continuing to be broken (in both directions). This is, however, by far the least serious of the likely consequences.
Changes in regional temperature and rainfall patterns, and their consequences for agriculture, will be far more significant. These are extremely complex and cannot be predicted with any great confidence, but some general trends are becoming evident. One is that some currently fertile areas, mainly in continental interiors, will become a lot drier. We are already seeing a pattern of increased droughts, in Africa, Australia, China and the USA, where water sources are being used up faster than they are being replenished. This is likely to have a significant effect on agricultural production, since this is one of the major users of fresh water.
In part compensation, certain other regions of the world which are now too cold for agriculture will become available. However, it takes a very long time to develop fertile soils suitable for agriculture, and the total area of agricultural land is likely to diminish significantly. Meanwhile, it is virtually certain (for demographic structural reasons – lots of young people in many parts of the world) that barring devastating epidemics, warfare or famine, the world's population will continue to rise until the middle of this century, up from the current 6.8 billion to around 9 billion, with obvious implications for the demand for food, fresh water and living space – and CO2 production.
It has been suggested that some areas may paradoxically become cooler, at least for a while before the general increase in temperatures pulls them back up again. The best-known possible cause has been the stopping of the Gulf Stream (also known as the North Atlantic Drift or the North Atlantic Current, which is part of the Atlantic meridional overturning circulation - AMOC) as a result of a surge of fresh water from melting polar ice. This currently keeps North-West Europe (including the UK) several degrees warmer than it would otherwise be, so the short-term impact of stopping it could be considerable. This was the trigger used for the sudden cooling so exaggerated in the movie The Day after Tomorrow. A preliminary study showed that the volume of flow of the Gulf Stream was about 30% lower in 2004 than it was in 1957, but more recent and thorough work has concluded that this was due to a normal cycle of changes in flow rates. Such a cooling effect is no longer considered to be a major risk in comparison with the global rise in temperatures.
Sea level change and oceanic acidification
The melting of ice brings me on to the third major concern, which is the changes in sea level. These are already happening, partly because the oceanic water expands as it warms up, but that effect is relatively small. It is also worth pointing out that the melting of ice already floating on the ocean (such as the Arctic Ocean ice cap centred on the North Pole, or floating ice sheets around Antarctica) has no direct effect on sea levels because the ice is already displacing water. The threat comes from the melting of ice which is currently on land. Some 89% of such ice covers Antarctica, another 10% is on Greenland, and the remaining 1% is in the form of glaciers and smaller ice caps scattered around the world.
To give an idea of the potential scale of the problem: if the West Antarctic Ice Shelf – WAIS – were to melt or slide into the ocean, global sea levels would rise by an average of about 3-3.5 metres (its the total disappearance would cause a 5 metre rise, but this is now thought unlikely). The disappearance of the Greenland ice would add 7 metres. If all ice went, the total rise in sea level would be around 70 metres (220-240 feet) but we don't need to worry about that – according to our current understanding, it would take many millennia, and in such extreme circumstances it is unlikely that humanity would be around to see it. For a more realistic threat, it is worth bearing in mind that sea levels were 3-6 metres higher during the last interglacial period although the global mean temperature was then only 1-2 degrees warmer than now. Current expectations are for an increase in temperature of at least 2 degrees by the end of this century, and it could be a couple of degrees more.
The conventional models of ice melting show that even the WAIS and Greenland ice would take millennia to melt. However, that assumes the ice would melt while still on land; a very slow process. It is now recognised that this isn't necessary, all it has to do is transfer to the ocean to provide the rise in sea level. There are signs that this is already happening, with the rate of movement of many glaciers showing a marked increase, some having accelerated to several times the rate of a couple of decades ago. This seems to be mainly because they are being lubricated by meltwater flowing underneath them, but the penetration of meltwater down from the surface is also causing the ice to fragment vertically, making it more likely to collapse. These effects are greatly speeding up the transfer of ice to the sea. This could result in a much faster rate of increase of sea level, with an average rise of between 0.8 and 2.0 metres by 2100 now being projected (more than double that forecast in the IPCC report). Such a rise would have all sorts of unwelcome consequences for port cities and low-lying areas in which large numbers of people live and farm. There is, of course, a considerable lag between an increase in atmospheric temperatures and the melting of massively thick ice caps. What that means is that even if the average rise in temperature is held to just 2 degrees, the ice will continue to melt, and the sea level to rise, for centuries.
The most recent concern is ocean acidification, which is already happening. As temperatures increase, and the percentage of CO2 in the atmosphere continues to rise, more CO2 is absorbed by the ocean. This causes an increase in the acidity of the water, which potentially will have a serious effect on oceanic ecology as some creatures at the bottom of the food chain may find it impossible to cope. Coupled with world-wide over-fishing, this could result in fish disappearing from the human diet.
In conclusion: as the science firms up, the news concerning climate change keeps on getting worse in almost every respect. However, all is not (necessarily) lost. I will next consider what might be done about this, including ideas with potential for use in science-fiction stories.
How to Tackle Global Warming
What (if anything) can we do about climate change? What kind of measures might a realistic near-future SF story include?
There are basically four different approaches, most if not all of which may be needed in order to have a significant moderating effect on climate change. These are: to cut back CO2 production; to remove CO2 already in the atmosphere; to reduce insolation (heat received from the sun); and finally to adapt to the changes which are now inevitable, it being already too late to prevent some of the consequences of warming. I'll take each of these in turn.
Cut back CO2 production
This is the best known approach, or rather a whole cluster of different approaches under the same general heading. The techniques available range from the simple and obvious to the complex and difficult. The former are being applied already, to a greater or lesser extent in different places, but the latter will need strong political will on an international basis; i.e. they're not likely to happen until the consequences of climate change have become so obvious – and obviously bad – that not even short-termist politicians can ignore them.
Save energy - buildings: The relatively easy measures include changing building designs to minimise the need for heating in cold countries and for air-conditioning in hot ones. The former is well understood and already widely practiced; it requires good insulation standards, preferably including heat-recovery ventilation systems. The beauty of this is that most such measures can be retrofitted to most existing buildings, an important point given that complete replacement of our building stock will take a very long time. Measures to reduce air conditioning (likely to become increasingly important as the globe warms up) are less common and may be more difficult to apply to existing buildings. Some techniques are similar to the cold-climate ones – better insulation, smaller windows – but could also include installing an oversized 'floating' roof canopy, detached from the main structure, to provide shade without transmitting heat to the building. Some buildings are cleverly designed to have a ventilation system driven by natural convection, while 'green' roofs and walls – covered with plants – have been found to have a significant effect, not only in providing shade but in evaporative cooling. You do need a good water supply for these, though, which will be an increasing problem in many hot areas. Cooling systems using water circulating through underground pipes (a kind of reversal of the usual heat-pump heating system) may be more efficient than electrical air-conditioning.
Save energy – equipment and processes: Another well-known and much-practiced technique is the use of low-energy lights and appliances. Industrial processes are major users of power, an area which has probably received less attention so far than the domestic side.
Save energy – power generation: This is the major source of human-caused CO2 production, so non-polluting power generation has received a lot of attention in recent years, as demonstrated by the huge wind turbine farms sprouting up on land and in coastal areas. However, as is often pointed out, these aren't much good unless the wind blows. In fact, except for geothermal power, other sustainable power sources – hydro-electricity, tidal, wave and solar power – suffer from related problems in that the sources of power (even if reliable) are not constant, and may be a long way away from where they are needed. There is a potential solution to this, however; while AC current (in almost universal use) loses a lot of power when transmitted long distances, DC current does not. Until recently, converting DC to AC for domestic use was difficult, but solutions have been found. Some high voltage DC lines are already in use, and an international DC 'supergrid' has been proposed to link up Europe and North Africa. This will not only even out the supply from erratic sources such as wind power, but also provide access to solar power. Its proponents claim that a Europe-wide supergrid in conjunction with the full development of sources of sustainable power (mostly in the form of offshore wind farms) could reliably replace all of Western Europe's coal and gas power stations within thirty years.
Other alternatives being much discussed are the use of 'carbon capture' systems with fossil fuel power stations, by which the CO2 produced is trapped and pumped underground, and a revival in the use of nuclear power. The problems are that the carbon capture system is unproven (and some experts are dubious that it will work as advertised) and the supply of nuclear fuel is finite. Of course, if an economical source of fusion power could be developed that would solve most problems, but it's been 'coming soon' for about half a century and still seems a long way off, so it would be unwise to rely on that.
Interestingly, sustainable power is causing major divisions in the environmental lobby (a potentially fruitful source of SF plots). While all environmentalists are in favour of reducing CO2 production, some are also appalled by the alternatives, especially nuclear power, the visual blight of massive wind farms, and the potential effect on wildlife of huge engineering schemes such as the proposed tidal-power Severn Barrage in the UK. No doubt plans to cover vast areas of desert with solar collectors will result in similar protests.
These environmental protectionists argue that power generation systems do not need to be grand schemes. They believe that we should be thinking small-scale, with local generation of heat and power. Solar panels for water heating are commonplace now, and photo-voltaic solar cells are predicted to get a lot cheaper. These don't just work in hot and sunny climes; astonishingly, the world's major user of domestic PV cells is Germany, as a result of a scheme which provides significant financial rewards to people who sell their surplus power to the grid. However, while such schemes are well worthwhile and can reduce the demands on the power grid, the problem of the erratic supply of power from such sources can only be met by massive, interlinked, engineering projects.
Save energy – transport: This brings us onto another big polluter – transport. Much attention is being paid to road vehicles, with electric and hybrid (petrol/electric) vehicles in use and fuel cells being tested experimentally. Each of these systems, as presently conceived, has problems. Pure electric vehicles are limited to short-range use because of battery limitations (in both capacity and recharging time). Furthermore, recharging batteries by plugging them into the grid isn't going to help much unless the electricity is generated from sustainable sources, so that would need to be in place to gain the full benefit from electric cars. Assuming that eventually happens, a battery swap system is proposed to allow drivers to change battery packs at service stations in the same way that they now fuel up, although there are indications that very fast-charging batteries may be on the way somewhat later.
Hydrogen cells, which develop electricity by combining hydrogen and oxygen in a kind of reverse electrolysis (the only by-product being water) are at a much earlier stage of development. Hydrogen has to be manufactured (not currently a very clean activity) and special transporting, storing and dispensing arrangements would need to be put in place. This seems unlikely to be adopted on a large scale without major government start-up funding, because manufacturers won't develop and make fuel-cell cars unless they are confident that people will buy them in large quantities, people won't buy fuel-cell cars unless there is a comprehensive network of hydrogen filling stations, and companies won't manufacture and distribute hydrogen, or equip the filling stations to dispense it, unless there is a proven demand (or someone else provides the start-up funding).
Taking all of this into account, the best approach for the near future is to have an electric car with plug-in recharging plus an internal-combustion on-board generator to top up the batteries on a long run. This generator could be very small, as it would only need to supply cruising rather than full power. It could also run at a fixed speed, further improving efficiency. The next development stage will probably be all-electric, using high-capacity fast-charging batteries, with fuel cells possibly coming along later.
Of course, mass transport tends to be the most efficient way of moving people, at least in areas of high population density. Tram and other light-rail systems are proliferating and will probably continue to do so. Unfortunately, there is a major problem with aviation. The growth in this is very bad news for the environment, not only because of the large quantities of CO2 and other pollutants produced, but also because they get ejected high in the atmosphere where they are far more damaging than at ground level. It is very difficult to see what can be done to ameliorate this, apart from taxing air travel so highly that it once again becomes the privilege of the rich few, but this would be politically virtually impossible. Hydrogen fuel would help, but planes designed to use this are so far off that they don't even seem to be being considered at the moment.
A different approach to reducing vehicle pollution is to make fewer journeys. Modern communications technology makes it feasible for increasing numbers of employees to spend at least part of their time working from home instead of commuting into cities. There is also growing criticism of our exploitation of cheap fuel in amassing "food miles" (the distance food travels before it reaches local shops), one example being fish originating in Scotland being sent to Poland for preparation and packaging before being sent back to the UK for sale. This has led to a growth in the UK in "farmers' markets", which are limited to selling local produce, bypassing the big commercial distribution networks. This is another aspect of the "think small, think local" movement already identified in the section on power generation. This issue, combined with a likely increase in international instability caused by climate change, may well see traditional food importing countries like the UK reverting to more domestic local production. Our gardens of the future may well consist of vegetable plots, as in the Second World War.
Incidentally, one very bad idea is the use of farmland to grow crops for biofuels. This merely causes food shortages and leads to the stripping of native forest, thereby reducing biodiversity, reducing the capacity to absorb CO2 and potentially reducing rainfall by removing the moisture normally present in forests.
Making it happen – incentives: Clearly, the speed at which all of the above measures can be implemented (at least in free-market economies) depends on financial incentives, as demonstrated by the German PV cell experience. It has been suggested that the simplest and most fool-proof method of encouraging the most efficient and sustainable use of energy for all purposes would be to tax all fossil fuels at source, when they are removed from the ground. This would not only discourage the use of fossil fuels, it would make sustainable energy sources more competitive on price. The major problem is that this would require global agreement, and that is inconceivable in present circumstances (when countries can't even agree to tax all aviation fuel). Maybe much later, if the environment is sliding into chaos, by which time it would probably be far too late.
The population problem: As mentioned earlier, an underlying problem which is going to undermine all of the attempts to minimise CO2 production is the projected huge rise in the world's population, from about 6.8 billion now to around 9 billion by the middle of this century before stabilising at between 8 and 10 billion (estimates vary). Although population forecasting is notoriously unreliable, anything remotely like this will cause enormous problems even without climate change. Unless, of course, there were to be devastating famines, epidemics or wars, with death rates orders of magnitude greater than anything seen to date, which is hardly an attractive option. Add in the predicted effects of climate change in drying out continental interiors, and such appalling outcomes become more likely as starving, desperate populations try to move to more fertile lands (as is already happening in parts of Africa). It is hard to see a way to avoid this without drastic limits on childbirth, which even a dictatorship like China has struggled to enforce.
A different style of living: Can anything be done about coping with the population increase? The major problem is of course producing enough food coupled with the supply of fresh water, but the extra living space required will also be an issue, particularly since conventional housing developments use up a lot of land which might otherwise be growing crops. This suggests that different forms of living may be developed, possibly in the form of arcologies; huge buildings in which city-sized populations can live, work and play while occupying only a small fraction of the ground area of a conventional city – and also using up only a small fraction of the energy per person. By a not-so-strange coincidence, the novel on which I am (very intermittently) working, set a century into the future, takes place in such an arcology.
Remove CO2 already in the atmosphere
One of the major problems with churning out CO2 is that, once in the atmosphere, it persists for a very long time. This contrasts with other greenhouse gases such as methane, which disappear relatively quickly. Even if it were possible to stop all burning of fossil fuels immediately, the quantity of CO2 already in the atmosphere would remain higher than pre-industrial levels for centuries to come; which means that the Earth will inevitably continue to warm up for centuries. As a result, there is increasing interest in "geoengineering" – physically removing CO2 from the atmosphere, or finding other ways to increase CO2 absorption or to prevent the greenhouse effect.
Geoengineering is highly controversial because of worries that it may have unwanted consequences; for instance, increasing oceanic absorption of CO2 will increase seawater's acidity (something which is already beginning to happen) with potentially dire consequences for the marine ecosystem. It is therefore only being considered as a last resort, because climate scientists now believe that there is no chance of cutting CO2 production by enough to make much difference; in fact, before the current recession took effect, carbon emissions were still increasing by 3% a year.
Geoengineering techniques can be as simple as planting trees, but this only postpones the problem – at some point, the trees will die and their carbon will be released unless the trees can be processed in a way which prevents this. More drastic measures are therefore being considered. These include seeding the oceans with iron filings to encourage the growth of organisms which would trap CO2. However, apart from the acidification problem, a recent experiment failed to achieve the desired effect.
A more high-tech approach is to manufacture huge quantities of "scrubbers" which will physically remove CO2 from the atmosphere. Three different techniques have been proposed.
One is a "spray hangar" in which air is sucked in one end and blown out of the other after being sprayed with sodium hydroxide solution; this reacts with CO2 to form droplets of sodium carbonate. This is known to work, but in its present form requires a huge amount of energy.
An alternative is the "solar scrubber", using sun-focusing mirrors to heat a transparent tube filled with pellets of calcium oxide. As the temperature rises to 400 degrees C, air is blown through the tube and its CO2 combines with the chemical to form calcium carbonate; virtually all of the CO2 is extracted. The process can be reversed by doubling the temperature in order to drive off pure CO2 which can easily be captured; but of course, a safe way of disposing of it then has to be found. One possibility is to pump it into adjacent greenhouses in order to promote crop growth (a technique which is already being used).
The third option is the "air collector", which pumps air over an ion exchange resin, a polymer impregnated with sodium hydroxide, to which the CO2 adheres. It can later be washed out for disposal using humid air at only 40 degree C.
The benefit of these technologies is that there appears to be minimal risk of unintended consequences since all they do is extract CO2, a process which can instantly be switched off when no longer needed. The main drawback of the CO2 scrubbers is that millions of the things would be needed, at huge cost.
A different approach is to reduce the degree by which the sun heats up the Earth, by reflecting more of its rays back into space. As we have seen, ice fields reflect around 90% of the insolation (compared with 94% absorption in open water) and their melting is contributing to Arctic warming. One study calculated that reflecting an extra 1.8% of insolation would cancel out the effects of doubling the CO2 levels.
Various fanciful ideas have been proposed, such as dumping vast quantities of white polystyrene to float in the oceans (which could of course reduce their capacity to absorb CO2) or pumping sulphate particles high into the atmosphere to reflect the sun's rays (but this could cause catastrophic droughts in some regions, and would need constant renewal). A variation on the last one is to pump atomised seawater into stratocumulus clouds in order to increase their density and make them more reflective. This should work, but the processes of atomisation and of getting the water up to the clouds in such enormous quantities are obviously not trivial issues.
A more high-tech approach is to launch "sunshades" into space, in the form of discs of silicon about 60 cm across, just a few micrometers thick and weighting 1 gram. Each would be covered with holes calculated to act like a lens, causing dispersion and dimming of the sunlight. They would be "steerable" using solar energy to keep them in the correct position and orientation. The proposal involves launching containers, each carrying a million discs, from huge electromagnetic rail guns, towards the L1 Lagrange point where the Earth's and the sun's gravities cancel out. It has been estimated that twenty rail guns, each 3 km high and working around the clock to launch one container every five minutes for ten years, could achieve the 1.8% reduction, and it is hoped that the discs could last for up to 50 years.
The danger with all of these techniques would be if they were relied on to cancel out the effect of rising CO2 levels, thereby allowing CO2 to build up to high levels. Should the regular renewal of the sunshades then fail for any reason, the consequences to the climate of being suddenly exposed to high levels of atmospheric CO2 could be sudden and catastrophic.
A lower-tech approach would be to install reflective surfaces on the roofs of buildings or in the form of material covering desert areas, in those locations not required for solar heating or power systems.
Adapt to the changes
It is now accepted by climate scientists that any effective moves to reduce CO2 production will be too late to avoid some unpleasant consequences – our politicians have already failed us by avoiding the potentially unpopular measures required. Even the 2007 IPCC report predicted a rise in global average temperature of between 2 and 6.4 degrees C this century (depending on the effectiveness of CO2 reduction measures) and, as we have seen, a recent conference of climate scientists concluded that the outlook has worsened since that was written. An increase of 4 degrees by the end of the century now looks quite possible on present trends. So as well as continuing to try to minimise the warming effect, we are going to have to prepare for the consequences of a warmer world.
What this might mean is discussed in an article published in New Scientist on 28 February 2009 ("Surviving in a Warmer World"), which spells out the likely implications of a 4 degree warmer world. The picture painted is frankly horrifying. Much of the tropics could become uninhabitable due to drought, floods or extreme weather; the Amazon basin could become a desert, as could most of the USA, southern Europe, nearly all of Africa, southern Asia and all but a small part of Australia. Rising sea levels would mean that low-lying areas would vanish. The effect of all this would be to displace hundreds of millions of people. On the bright side, there would be some potential for reforestation due to rain brought by changing wind patterns, in west Africa and western Australia. However, the main areas suitable for habitation and farming would be Canada and Alaska, northern Europe and Asia, New Zealand, western Greenland and western Antarctica. These would become exceedingly crowded places, with the surviving population having to live in dense, high-rise accommodation to leave as much usable land as possible free for agriculture.
James Lovelock, who developed the "Gaia" theory, estimates that the devastation caused by climate change could result in the world's population reducing to 1 billion or less by the end of this century. Inevitably, there would be huge conflicts as displaced populations attempted to move to more favoured areas. As already indicated, many observers think that the first climate change war has been underway for years, in the civil war in the Sudan. Christians and Muslims had lived peacefully side-by side in Sudan's Darfur province for centuries, but the trigger for their vicious war (in which 200,000 have already died and around two million been displaced) has been a dramatic reduction in rainfall over the past few decades, leading to increasing desertification and a conflict over the remaining usable land. If the regional climate projections are right, similar problems are likely to occur throughout the tropics during this century.
Other climate impact specialists consider that the worst consequences can be reduced, provided that we start planning and acting now, by determinedly adopting the kind of measures discussed in this survey. It's too late to prevent a lot of problems, but it's worth doing all we can to minimise the future scale of them, since that could prevent a bad situation from becoming utterly appalling. At the very least, slowing down the warming process would give us more time to adapt. The political issues and pressures generated by all this are a potential source of material for near-future fiction.
Even if world leaders really begin to address this problem effectively, some changes will have to be made. The rising sea level, combined with more, and more violent, storms means that it would generally be futile to continue defending low-lying coastal areas. To give one well-known example, there is no point in the long term in trying to protect cities like New Orleans. This is already beginning to happen in a small way, with the evacuation of the 1,400 inhabitants of Papua New Guinea's Carteret Islands, and there are similar plans to abandon other low-lying oceanic islands. The prospect of millions of Bangladeshis moving into India as their land floods will raise problems on a very different scale.
Water shortages resulting from a combination of climate change and population growth will also require some changes to farming to get the maximum value out of agricultural land. One consequence is that meat-eating will have to diminish because, for the same food value, animal farms use farmland and water at several times the rate of crop farms. So the only farm animals likely to survive will be those which can live on poor quality pasture unsuitable for agriculture. To make matters worse, fish stocks will continue to shrink, not just through overfishing but through the increasing acidification and deoxygenation of the oceans. The water shortages will almost certainly end the current squeamishness about genetically-modified crops; to produce enough food, it will be necessary to develop drought-resistant strains.
Even so, a switch to a largely vegetarian diet wouldn't provide a complete solution. Crops not only use up a lot of water, our commercial farms are also heavily dependent on oil, for farm machinery, transport and fertiliser. Reductions in the use of fossil fuels to cut back on CO2 production, combined with an increasing shortage of oil as cheap sources are used up, will make traditional crop-growing far more difficult and expensive. A recent UK TV programme on "farms of the future" predicted the decline of large-scale crop growing in favour of local "vertical farms", based on hedges and trees producing fruit, nuts and edible leaves, which can provide several times the food value of the same area of arable land. These require very little work or other resources to grow, but they are much more labour-intensive to collect.
That just about wraps up my survey. In a nutshell, climate change is accelerating, and if we wish to avoid some rather horrendous consequences, we need to put a far higher priority on taking the kind of preventative and precautionary measures I have been describing. However, I am not very optimistic of success; given humanity's track record for burying its head in the sand for as long as possible when faced with difficult decisions, I think that we are likely to do too little, too late. An analysis of world population issues contains some sage words which should provide food for thought (and SF plots):
Planning a world for highly cooperative, antimaterialistic, ecologically sensitive vegetarians would be of little value in correcting today's situation. Indeed, a statement by demographer Nathan Keyfitz (1991) puts into perspective the view that behavioral changes will keep H. sapiens below social carrying capacity:
"If we have one point of empirically backed knowledge, it is that bad policies are widespread and persistent. Social science has to take account of them/" [our emphasis]
In short, it seems prudent to evaluate the problem of sustainability for selfish, myopic people who are poorly organized politically, socially, and economically.
Much the same might be said about responses to climate change.
I hope that all of this provides some useful material for the SF community; certainly there is scope for a wide range of backgrounds, from best-case to worst-case. The novel on which I'm working was intended to represent a likely future but, in the light of the latest information, is now looking to be at the optimistic end of the spectrum!