Global Warming and SF – Part 2

A few weeks ago I summarised the current state of the developing understanding among climate scientists concerning the increasing rate of change in our climate. Even the 'most-likely' scenarios are now looking grim – the worst-case ones don't bear thinking about. So, what (if anything) can we do about it? 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. 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 and 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 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.

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 in Part 1, 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 6.4 billion now to around 9 billion by the middle of this century. 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. 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, 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.

This subject is taking more space to cover than I expected, so the other possible measures to tackle global warming will have to wait until Part 3…