Next: Technology and the Environment II
Lecture 9: Technology and the Environment: An Optimistic View
Over the past few weeks we've discussed the harm that engineers do, whether by accident or design. Perhaps the most serious charge that can be made against engineers is that they are the primary agents of environmental destruction. (This, for example, is one of the Unabomber's reasons for targetting engineering faculty.) Even apparently beneficial applications of engineering, such as improved health technologies, increase population growth and the consequent pressure on the planet's limited resources. In this lecture, we will examine some predictions of imminent environmental disaster, and show that, contrary to popular belief, we can expect the continuation of current trends to bring us a future of health, prosperity and abundance.
``A minimum of 3,500,000 people will starve to death this year, mostly children. But this is a mere handful compared with the nunmbers that will be starving in a decade or so. And it is now too late to take action to save many of those people.''
That was written by Dr Paul Ehrlich in `The Population Bomb', published in 1968. It offers a prediction for the 1970's: that vast numbers of people, compared with which 3,500,000 would be a `mere handful', would starve to death.
Twenty-two years later, Ehrlich published The Population Explosion. Were his 1968 predictions correct? No. All through the seventies, the world's food production actually increased faster than population. ( Explosion, p.68.) Did vast numbers starve? No. There were famines in Africa, where Ehrlich estimates that about five million children died from hunger-related causes every year during the Eighties, but nowhere else ( Explosion, p.80). Five million annual deaths certainly constitute a tragedy, but a tragedy largely unrelated to population growth -- the famines in Eritrea and the Sudan were deliberate acts of repressive governments, withholding food from certain regions as a military tactic against popular uprisings. But even if we were to count all these deaths as due to overpopulation, they scarcely add up to the `vast numbers' Ehrlich predicted in 1968. How could he have been so wrong?
If we examine the rate of population growth in the countries of North America or Western Europe over the past few centuries, we see a repeated pattern: initially there is a high birth rate and a high rate of neonatal and infant mortality; the two rates balance out to give a stable, low population. Then, improved health practices and better sanitation reduce the death rate, and the population increases rapidly for a while. But this growth does not increase without limit. Within a few generations, the society adjusts to the new conditions, and family sizes drop, giving us the present situation of a stable, higher population.
Thus the graph of population growth over time is not an endlessly-growing exponential, but an S-shaped curve; stability, a short period of rapid growth, followed by stability at a higher level. It is too soon to say for sure, but it appears that the same levelling-off is beginning to occur in the more prosperous of the LDCs. UN predictions for world population in the year 2000 have been revised downwards several times since Ehrlich's book was written. We might expect world population to stabilise at a few billions above the current level by some time in the next century. Whether this is too high or too low a figure is a question of values, not of fact, and we will not discuss it further in this section.
Resources
``We have only limited supplies of any natural resource. For some resources, such as oil, we have already used up most of what's there. In any case, the more we use, the less will be left for our descendants."
This seems undeniable. Nevertheless, there are those who would argue to the contrary. For example, Harvard economist Julian Simon, in his book `The Ultimate Resource', argues as follows:
Comparison of current rate of use with known reserves of any resource will always make it appear that the reserves are nearly exhausted. This has nothing to do with how much of the resource actually exists. Because it costs money to identify deposits of a resource, there is simply no point in seeking out more than is needed for the next few decades. But as soon as we approach the limits of known reserves, it will become worthwhile to look for more. And, in the past, we have always found more.
So how can we tell whether we're really approaching the limits of a resource? One way is to look at its price; if a resource is becoming scarce, we would expect its price to go up. What do we find, if we look at the prices of copper, coal, oil, and other minerals over the last century? Surprisingly enough, we find that the prices of all these resources have fallen, whether we look at the price in constant dollars or the price in hours-of-labor-at-average-wage required to buy unit quantity of the resource.
Is Simon confusing `we don't know what the real limits on resources are' with `there are no real limits on resources'? No; he argues that both statements are true. How can the latter assertion be supported?
A shortage, of, say, copper, will only be a problem for our descendants if that shortage impoverishes their lives in some way. People do not in general value copper for its aesthetic qualities, but because it can be used to accomplish certain tasks. Most of the copper mined at present is used as an electrical conductor, in, for example, telephone cables. The development of fiber-optics provides another way of accomplishing the same task. As long as technological progress continues, we can expect to find cheap, plentiful substitutes for most `scarce' materials.
Furthermore, many of the resources we are currently consuming are not being used up, merely converted to other forms. If copper ever did become scarce, it would become worthwhile to mine it from discarded transformers and other appliances. It is reasonable to expect robots capable of doing this mining to become available within the next few decades.
But other resources, such as the area of the United States not yet covered by concrete and asphalt, are finite and determinate. Aren't these being used up?
Simon presents statistics to show that the fraction of the US land surface covered by buildings and motorways is less than 1% -- far less than the fraction covered by forests. Moreover, the area covered by forests has not decreased significantly since the beginning of the century.
Pollution
Even if resources are not in imminent danger of exhaustion, should we not look at the other side of the equation? Don't the production and consumption of material goods produce pollution, and so add to the burden on the environment? Aren't the most industrialised nations also the most unhealthy and polluted, and isn't the problem rapidly getting worse?
Let us consider two examples from history. In the eighteenth century, the Thames was London's chief sewer. The only life it supported was a teeming bacterial soup. One particularly warm summer, the House of Commons was forced to go into recess by the smell of the adjacent river. London's air quality was also poor; use of coal for domestic heating led to `pea-souper' fogs. A particularly heavy fog in 1952 killed several thousand people.
Both of these problems have now been greatly ameliorated. Improvements to the sewer system, and, in more recent years, regulation of industrial wastes, have cleaned up the Thames, and fish are re-populating its lower reaches. The clean-air regulations enacted after the 1952 fog have relegated the `pea-soupers' to history. Over the same period, the population of London has grown, the level of consumption by its inhabitants has increased, and their use of technology has increased. This is sufficient to show that there is no necessary connection between these factors and the level of pollution.
If we are concerned with the effects of pollutants on our health, we must look to some objective measure of health. Life expectancy is one such measure. The statistics are reliable and readily available: they show that life expectancy increases as nations go from a rural to an industrial economy, and that the inhabitants of the most industrialised nations are, in general, the longest-lived.
Nevertheless, we might be concerned about more subtle effects on our health. We know that, as a result of the by-products of technology, our environment contains small amounts of an increasing number of poisons, for example, cadmium from cell phone batteries, or low-level radiation from nuclear plants. While these may not be present in large enough quantities to kill people, isn't it reasonable to assume that small quantities of harmful materials must have some insidious effect, perhaps contributing to chronic fatigue syndrome or gradually weakening our genetic material?
Research by toxicologist Edward Calabrese of the University of Massachusetts at Amherst, reported in the September 2003 issue of Scientific American, suggests just the reverse. He has documented an effect known as `hormesis': many agents which are damaging in large quantities may, in lower concentrations, actually strengthen the body by stimulating it to repair itself. (This should not be confused with the claims made by homeopathy, which asserts that astronomically low concentrations of toxins -- less than one molecule of a toxin in an ocean of water -- can be beneficial; there is no evidence that this is true.)
Calabrese argues that current levels of pollution may actually be too low to obtain the maximum benefits from hormesis, and that we would all possibly benefit from higher levels of some pollutants.
In conclusion: there are particular cases in which pollution has become a serious problem. These cases are amenable to legislative and technological fixes. They do not call into question our way of life or our level of consumption.
Global Warming and the Rainforests
We often hear statements such as ``the rainforests are the lungs of the planet'', implying that the rainforests are particularly valuable in removing carbon dioxide from the atmosphere. Let us examine this claim.
We begin by recalling some elementary biochemistry, the carbon cycle:
Four billion years ago, there was no free oxygen in the atmosphere; Earth's atmosphere at that time was rather like that of Venus, with a lot of free carbon dioxide. The first plant life used photosynthesis to split this carbon dioxide into oxygen, which was released to the atmosphere, and carbon, which was used to form glucose and other organic compounds, all of which end up in the plant biomass. Oxidizing this biomass, by burning the plant or allowing it to decay aerobically, would exactly consume the net amount of free oxygen released by the plant during its lifetime.
Since we currently have free oxygen in the atmosphere, there must be a lot of unoxidized biomass on the planet. Some of this exists as living plants, some as fossil fuels.
Now, what does a mature rainforest contribute to this cycle? If we concentrate on mature, first-growth forests, we note that the total biomass of the forest is constant; new trees are growing at the same rate as old trees are dying and decaying. This is what ``mature'' means. But this must mean that the net contribution of the forest to the oxygen/carbon-dioxide economy is nil! The only way the forest could effect a net reduction in the amount of carbon dioxide would be if dead biomass remained unoxidized, that is, turned to coal.
This does not happen; there are some ecologies in which new fossil fuels are formed, notably peat bogs, where high acidity prevents decay. But a mature rainforest is at the opposite end of the spectrum from the almost-sterile peat bog; in its teeming environment, dead wood is quickly broken down and oxidized. Should the dead wood happen to decay anaerobically, in the mud at the bottom of forest pools, it produces methane. A molecule of methane contributes as much to the greenhouse effect as four molecules of carbon dioxide.
So we should see the rainforest as a neutral element with respect to global warming. It's a stockpile of carbon, taken out of circulation long ago, currently contributing nothing. Of course, if we clearcut the forest and burned the timber, or left it to rot, this would bring about a net increase in carbon dioxide. But if, after clearcutting, we turned the timber into lumber, pulp and paper products, then re-seeded, we would actually be reducing carbon dioxide levels. Making paper is just as good as making coal; it stores the carbon in unoxidized form. And the new growth in the re-seeded forest is now producing new biomass, taking more carbon dioxide out of the atmosphere.
So, considering only the question of global warming, the most environmentally sound policy would be to clearcut all old-growth timber immediately, then re-seed.
Prospects for the Future
Nature is indifferent to human survival and human values. She periodically covers the world with ice, drowns the continents with tidal waves, and pollutes the atmosphere with volcanic eruptions. Ninety per cent of the species that have ever existed were wiped out by Nature. If Nature does not kill us in some other way first, the sun will eventually swell to engulf the earth, exterminating our descendants.
We can expect to find comfort and security in the world only to the extent that we have brought nature under our control. We have already progressed some way in this direction, but we are still tied to one planet. Soon we will populate other planets, or create artificial dwellings in space. We will fashion great hollow cylinders, filling them with genetically engineered crops and animals grown from the DNA of endangered species. We will develop tools to control the sun, and create other suns when this one grows old. No-one can set a limit to what technology may accomplish -- consider that eminent men once denied the possibility of flight, of splitting the atom, or of travelling to the Moon. They have all been proven wrong, often within their own lifetimes. All that is needed for a thing to become practicable is that we focus our efforts on its accomplishment. The mechanism of the free market ensures that our efforts will be focused on just those problems that will bring the greatest good to society. Or, rather, since there is no such thing as the good of society beyond the good of the individuals who constitute the society, each individual should be the judge of what's good for him or her. Thus, nothing is required to focus our efforts but to let each individual choose freely. Market forces will then ensure that technological progress occurs in just those areas corresponding to the resultant of individual wishes. To intervene in this process is paternalistic and undemocratic; such intervention could be justified only by an imminent threat of disaster. But, as argued in the first section, there is no clear evidence for such a threat.
So if we ask what to expect of technology in the future, the answer is that we should expect the fulfillment of all our dreams. One of our oldest dreams is immortality: to conquer the final enemy that nature has set against us. And two techological routes to this dream lie open.
The first route relies on the emerging discipline of nanotechnology, which we will be studying in greater depth in a few weeks. Nanotechnology offers the possibility of constructing tiny robots, small enough to float within the bloodstream. We know that such machines can exist -- our bloodstream is already full of them, macrophages, leucocytes, and so on, busily repairing damage and fighting invasions of bacteria. But these repair machines eventually wear out, and we die. What nature can build from DNA and proteins, we can build from other materials. And our repair machines, being the product of intelligent design rather than nature's billion years of trial and error, need not suffer from built-in obsolescence. In fact, we can improve on our current bodies, removing such design flaws as the appendix, eliminating short-sightedness, and augmenting our intelligence with built-in processors.
This last possibility suggests the second route to immortality. Professor Hans Moravec of Carnegie-Mellon proposes in `` Mind Children", that we can achieve immortality by transferring our thought patterns to the circuits of a computer. The outline of this plan is simple enough: suppose one neuron in your brain were damaged. Replace it with a prosthetic neuron. This would be a more complex device than the artificial neurons I mentioned in Lecture 3: a real neuron is more than a switch. But it is still a physical system, whose action -- firing or not firing -- is determined by the inputs it receives from other neurons; and it would be strange if we could not eventually model its behaviour.
Now imagine the biological brain gradually dying, one neuron at a time. As each neuron dies, we replace it with an artificial neuron. To the neuron's neighbours, nothing has changed: they are still receiving the same electrical signals as before. We can add delays to the circuit if necessary, so that the artificial neurons have the same slow reaction times as their biological predecessors. So if the original, biological, brain had reacted to incoming pain signals by sending a message to the vocal cords: ``Say `ouch!'" -- the modified brain will behave in the same way.
It is not necessary that the artificial neurons should physically resemble their biological counterparts; once all the brain's neurons have been replaced, the artificial brain might be reduced in size, and its speed of operation increased. Several copies of the brain might be made, as a precaution against accident.
This route to immortality emphasises the unique character of humanity among
the other species of life: our essential nature is our intelligence, and
changing the substrate of that intelligence from ionic currents in tissue to
electrical currents in silicon would not affect our essence.
Other species do not possess comparable intelligence, and are hence qualitatively
different from us.