by S. Matthew Liao (New York University),
Anders Sandberg (Oxford), and Rebecca Roache (Oxford)
February 2, 2012
Ethics, Policy and the Environment
There is ample evidence that climate change is likely to affect adversely many aspects of life for all people around the world, and that existing solutions such as geoengineering might be too risky and ordinary behavioral and market solutions might not be sufficient to mitigate climate change.
In this paper, we consider a new kind of solution to climate change, what we call human engineering, which involves biomedical modifications of humans so that they can mitigate and/or adapt to climate change. We argue that human engineering is potentially less risky than geoengineering and that it could help behavioral and market solutions succeed in mitigating climate change.
We also consider some possible ethical concerns regarding human engineering such as its safety, the implications of human engineering for our children and for the society, and we argue that these concerns can be addressed.
Our upshot is that human engineering
deserves further consideration in the debate about climate change.
There is wide agreement that climate
change will affect the lives of all people around the world in areas
such as food production, access to water, health, and the
environment. Indeed, it has been estimated that millions could
suffer hunger, water shortages, diseases, and costal flooding as a
result of global warming (IPCC 2007; Stern 2007).
There is lively debate in the relevant literature about these different kinds of solutions.
Each kind has its merits and demerits (Ekins and Barker 2001; Keith 2000; Kollmuss and Agyeman 2002).
For example, an advantage of behavioral solutions is that they are ones that most of us could easily physically perform. Their disadvantages include the fact that many people lack the motivation to alter their behavior in the required ways, and the fact that even if widely adopted, behavioral changes alone may not be enough to reduce greenhouse gas emissions sufficiently to mitigate climate change.
An advantage of market solutions is that they could reduce the conflict that currently exists for companies between making profit and minimizing undesirable environmental impact.
A disadvantage is that effective market solutions such as international emissions trading require workable international agreements, which has thus far seemed difficult to orchestrate.
For instance, it has been argued that the Kyoto Protocol has produced no demonstrable reductions in emissions in the world (Prins and Rayner 2007). Moreover, it has been estimated that to restore our climate to a hospitable state requires us to cut our carbon emissions globally by at least 70 percent (Washington et al. 2009).
Given the inelastic and rising demands for petrol and electricity, there are also issues about whether market solutions such as carbon taxation can by themselves be enough to deliver reductions of this magnitude. An advantage of geoengineering is that, in theory, its impact could be significant enough to mitigate climate change (The Royal Society 2009).
Its disadvantages include the fact that,
in many cases, we lack the necessary scientific knowledge to devise
and implement geoengineering without significant risk to ourselves
and to future generations. Some have therefore argued that no
institution or nation-state has the right to attempt geoengineering
We call this kind of solution human
engineering. It involves the biomedical modification of humans to
make them better at mitigating climate change. We shall argue that
human engineering potentially offers an effective means of tackling
climate change, especially if implemented alongside the sorts of
solution that we have already described.
Also, as we envisage it, human
engineering would be a voluntary activity - possibly supported by
incentives such as tax breaks or sponsored health care - rather than
a coerced, mandatory activity.
Note that these examples are meant to be suggestive and we are not wedded to these particular examples. Although we think that these examples are not implausible, there may be better examples to illustrate our point that human engineering should be taken seriously.
We invite readers to come up with such
More recently, it has been suggested livestock farming in fact accounts for at least 51% of the world’s greenhouse emissions (Goodland and Anhang 2009).
But even by the more conservative estimate, close to 9% of human CO2 emissions are due to deforestation for expansion of pastures, 65% of anthropogenic nitrous oxide is due to manure and 37% of anthropogenic methane comes directly or indirectly from livestock.
Some experts estimate that each of the world’s 1.5
billion cows alone emit 100-500 liters (about 26-132 gallons) of
methane a day (Johnson and Johnson 1995). In addition there are
sizeable negative impacts on water availability and biodiversity (Steinfeld
et al. 2006). Finally, emissions from livestock is expected to
increase very dramatically (Goodland and Anhang 2009).
Indeed, even a minor
(21-24%) reduction of red meat consumption would achieve the same
reduction in emissions as the total localization of food production,
i.e., having zero ‘food miles’ (Weber and Matthews 2008).
While eating red meat with added emetic (a substance that induces vomiting) could be used as an aversion conditioning, anyone not strongly committed to giving up red meat is unlikely to be attracted to this option. A more realistic option might be to induce mild intolerance (akin, e.g., to milk intolerance) to these kinds of meat.
While meat intolerance is normally uncommon (Aparicio et al. 2005), in principle, it could be induced by stimulating the immune system against common bovine proteins. The immune system would then become primed to react to such proteins, and henceforth eating ‘eco-unfriendly’ food would induce unpleasant experiences.
Even if the effects do not last a lifetime, the learning effect is likely to persist for a long time. A potentially safe and practical way of delivering such intolerance may be to produce ‘meat’ patches - akin to nicotine patches.
We can produce patches for those animals that
contribute the most to greenhouse gas emissions and encourage people
to use such patches.
Human ecological footprints are partly correlated with our size. We need a certain amount of food and nutrients to maintain each kilogram of body mass. This means that, other things being equal, the larger one is, the more food and energy one requires. Indeed, basal metabolic rate (which determines the amount of energy needed per day) scales linearly with body mass and length (Mifflin et al. 1990).
As well as needing to
eat more, larger people also consume more energy in less obvious
ways. For example, a car uses more fuel per mile to carry a heavier
person than a lighter person; more fabric is needed to clothe larger
than smaller people; heavier people wear out shoes, carpets, and
furniture more quickly than lighter people, and so on.
Since weight increases with the cube of length, even a small reduction in, e.g., height, might produce a significant effect in size, other things being equal (To reduce size, one could also try to reduce average weight or average weight and height, but to keep the discussion simple, we shall use just the example of height).
Reducing the average U.S. height by 15 cm would mean a mass reduction
of 23% for men and 25% for women, with a corresponding reduction of
metabolic rate (15% to 18%), since less tissue means lower nutrients
and energy needs.
this, there are several ways by which we could reduce adult height
It would simply
involve rethinking the criteria for selecting which embryos to
somatostatin (an inhibitor of growth hormone) is being studied as a
safer alternative (Hindmarsh et al. 1995).
Birth height has an even stronger effect for adult height. If one is born at the lower edge of the normal distribution of height, this tends to produce ≈15 cm shorter adult height. Gene imprinting has been found to affect birth size, as a result of evolutionary competition between paternally and maternally imprinted genes (Burt and Trivers 2006).
Drugs or nutrients that either reduce the expression of
paternally imprinted genes, or increase the expression of maternally
imprinted genes, could potentially regulate birth size.
As a way to mitigate climate change, they proposed that
Britons should consider having no more than two children per family.
While the primary reason for promoting education is
to improve human rights and well-being, fertility reduction may be a
positive side-effect from the point of view of
Like education, there are many other, more compelling reasons to improve cognition, but the fertility effect may be desirable as a means of tackling climate change. Even if the direct cognitive effect on fertility is minor, cognition enhancements may help increase the ability of people to educate themselves (Sandberg and Bostrom 2006), which would then affect fertility, and indirectly climate change.
shortly consider the effectiveness of such an indirect strategy for
tackling climate change.
If people were generally more willing to act as a group, and could be confident that others would do the same, we may be able to enjoy the sort of benefits that arise only when large numbers of people act together.
altruism and empathy may help increase the chances of this occurring
(Dietz et al. 2003; Fehr et al. 2002; Gintis 2000).
The fact that many environmental charities campaign to
raise awareness of such suffering as a way of increasing donations
supports this assumption.
While altruism and empathy have large cultural components, there is evidence that they also have biological underpinnings. This suggests that modifying them by human engineering could be promising. Indeed, test subjects given the prosocial hormone oxytocin were more willing to share money with strangers (Paul J. Zak et al. 2007) and to behave in a more trustworthy way (P. J. Zak et al. 2005).
Also, a noradrenaline reuptake inhibitor increased social engagement and cooperation with a reduction in self-focus during a mixed motive game (Tse and Bond 2002). Similar effects have been observed with SSRIs in humans and animal experiments (Knutson et al. 1998).
Furthermore, oxytocin appears to improve the capacity to read other people’s emotional state, which is a key capacity for empathy (Domes et al. 2007; Guastella et al. 2008). Conversely, testosterone appears to decrease aspects of empathy (Hermans et al. 2006) and in particular conscious recognition of facial threats (van Honk and Schutter 2007).
Neuroimaging work has also revealed that one’s willingness to comply
with social norms may be correlated with particular neural
substrates (Spitzer et al. 2007). This raises the likelihood that
interventions affecting the sensitivity in these neural systems
could also increase the willingness to cooperate with social rules
Others like them might include increasing our
resistance to heat and tropical diseases, and reducing our need for
food and water.
To answer this question, it is useful first to make explicit an assumption that we are making, namely, ordinary behavioral solutions such as driving less and recycling more and market solutions such as taxation and emissions trading are by themselves inadequate to mitigate climate change.
We assume this in part because there is ample evidence that this may be the case (Rahmstorf et al. 2007; U.N. Environment Program 2008) and because a number of experts on climate change seem to take far riskier solutions such as geoengineering seriously (House of Commons Science and Technology Committee 2010).
If behavioral and market solutions were by themselves sufficient to mitigate climate change, it would not be necessary to take geoengineering seriously. Suppose that we should take geoengineering seriously and that behavior and market solutions are by themselves inadequate to mitigate climate change.
There are at least two reasons to take human engineering seriously.
We shall explain each point
In contrast, at least the human engineering solutions we have described rely on tried-and-tested technology, whose risks, at least at the individual level, are comparatively low and well known.
For example, PGD - the process that would enable us to select smaller children - is an accepted practice in many fertility clinics.
Or, oxytocin, which could be
used to increase empathy, is already used as a prescription drug.
Furthermore, given that human engineering applies at the level of
individual humans, it seems that we can better manage such risks
than the risks imposed by something like geoengineering which takes
place on a much larger, global, scale. If one should take
geoengineering seriously, and if human engineering has the potential
to mitigate climate change while be less risky than geoengineering,
this seems to be a good reason to take human engineering seriously.
For one thing,
pharmacologically induced altruism and empathy could increase the
likelihood that we adopt the necessary behavioral and market
solutions for curbing climate change. Or, pharmacological meat
intolerance could make the behavioral solution of giving up red
meat much easier for those who want to do so but who find it too
However, if we were able to scale the size of human beings, then given the same fixed allocation of greenhouse gas emissions, some families may be able to have more than two children.
Human engineering could therefore give people the
choice between having a greater number of smaller children or a
smaller number of larger children.
Cognitive enhancement, if effective at reducing birth rates, could enable China to limit or dispense with its controversial, coercive one-child policy. But even if the effect of cognitive enhancement on birth rates is disappointing, improved cognition is itself of great value.
Or, consider pharmacological meat intolerance: if this method is effective at reducing greenhouse gases that result from the farming of certain kinds of animals for consumption, it could reduce the need to tax undesirable behavior (such as consuming goods that are most damaging to the environment).
But even if its effect on greenhouse gases is disappointing, the health benefits of eating less red meat and the reduction in suffering of animals farmed for consumption are themselves positive goods.
In general, as well as helping to mitigate climate change,
human engineering could also help solve some other serious problems
of the modern world: smaller people, more considerate people, and
lower meat consumption, could, for example, help address the
problems associated with unsustainable energy demands and water
However, as with all biomedical treatments - including those routinely prescribed by medical professionals - human engineering still carries risks. The type and severity of risk will vary from procedure to procedure. There could, for example, be side-effects of making children smaller by giving them hormones. Indeed, the steroid treatments currently used to treat growth abnormalities may risk triggering an early onset of puberty or other hormonal imbalances.
Also, somatostatin analogues may increase the risks of gallstones (Ahrendt et al. 1991). Or, increasing altruism and empathy using oxytocin might make a community more vulnerable to those who would take advantage of other people’s trust and generosity.
In fact, a study found that when
informed about breaches of trust in their community, people are less
likely to modify their trusting behavior if they have been given oxytocin (Baumgartner et al. 2008; Kosfeld et al. 2005). The
possibility of these risks means that if people are to be persuaded
to undergo human engineering, the risks associated with it must be
This is a very real possibility, since people are generally less tolerant of risks arising from novel, unfamiliar technologies than they are of risks arising from familiar sources (Slovic 1987; Starr 1969). To counter this effect, it is worth remembering that some of the technology involved in human engineering - such as PGD and oxytocin - is already safely available for other uses, and that in non-climate change contexts, our society has been willing to make biomedical interventions on a population-wide scale.
For example, fluoride is deliberately added to water with the aim of fortifying us against tooth decay, even though doing so is not without risks. Similarly, people are routinely vaccinated to prevent themselves and those around them from acquiring infectious diseases, even though vaccinations can sometimes even lead to death.
that biomedical modifications are accepted in these other contexts,
and given that climate change is at least as serious as these other
problems, again it seems that we should consider human engineering.
Owing to space, we shall just mention one such concern here for illustrative purposes (Liao 2008).
In particular, Michael Sandel has argued that a problem with human enhancement is that it represents,
Given that human engineering is using biomedical means for the sake of climate change, some might worry that this problem would similarly be present in human engineering.
Indeed, a number of
environmentalists believe that it is precisely our interference with
nature that has given rise to climate change. These
environmentalists might therefore object to human engineering on the
ground that it too is interfering with nature.
Among other things, this view - at least in its unqualified form - implies (implausibly) that providing vaccination, offering pain relief to women in labor, and so on, are impermissible, since these acts interfere with nature.
Also, not every human engineering
solution involves ‘interfering’ with human nature, if by
‘interference’ one means making modifications to human beings. The
selection of a smaller child through PGD, for example, involves no
more interference with nature than the standard IVF process, a
process to which many people do not object.
As such, even those who
oppose interfering with nature should not rule out human engineering
on the ground that it involves interfering with nature, and should
even - in the interests of reducing the total extent of human
interference with nature - seriously consider supporting it.
But human engineering is also an ethical endeavor in that mitigating climate change can promote the well-being of many people and animals that are vulnerable to the effects of climate change, and, as mentioned before, it can play an important role in preserving nature at large.
Given this, it seems that even those who share Sandel’s disapproval of the,
consistently endorse consideration of human engineering.
Is it ethical for parents to make choices that may irreversibly affect their children’s lives? This is an important issue, but it is worth remembering that not all human engineering solutions that would involve children are necessarily controversial.
For instance, would we as parents really object to using cognitive enhancement on our children as a means of lowering birth rates? There is evidence that many parents are indeed happy to give their children cognitive enhancements.
For example, a great many parents -
perhaps even too many - are willing to give
Ritalin to their
healthy children so that they can concentrate and perform better at
school, even though Ritalin is intended for
children with ADHD and
certainly has side effects.
The extent to which we are concerned by this issue will vary from case to case. As a general remark, it is worth reminding ourselves why more controversial kinds of human engineering would be contemplated.
They might be contemplated because there is evidence that existing solutions for mitigating climate change are likely to fall short of their intended goals, and because millions could suffer hunger, water shortages, diseases, and costal flooding if climate change were not mitigated.
In the biomedical enhancement literature, some people believe that, however controversial a technology may be, parents have the right socially and biologically to modify their children as long as doing so would on the whole promote their children’s well-being, and as long as there exists no better means of achieving such an end (J. A. Robertson 1994).
Similarly, given the seriousness of climate change, and given the possible lack of alternative solutions, we might conclude that if a particular human engineering solution would on the whole promote a child’s well-being, then parents should also have a right to implement such a solution even if the solution is a controversial one.
everybody would subscribe to this line of reasoning, and we do not
have space here for a full treatment of it; however, it suggests
that we have reason not to rule out even controversial human
engineering solutions, but to weigh them against other options.
To motivate the ensuing discussion, we shall use the example of making people smaller, as that is one example that is likely to raise this sort of concern. Some people might worry that using human engineering to make people smaller would entail that the most disadvantaged members of societies would bear the brunt of the effort (and the associated risks) of preserving the environment.
For example, the most disadvantaged members of societies already tend to be smaller than non-disadvantaged members of societies (Jansen and Hazebroek Kampschreur 1997).
If one were to use financial incentives
to encourage people to be smaller, the most disadvantaged members of
societies might not have the option to refuse these incentives and
might therefore disproportionately bear the burdens of alleviating
For example, suppose that one were a sufficientarian (Crisp 2003), and believed that there is a ‘sufficiency’ level of height below which it would be disabling for anyone to be. One might make sure that those who are expected to be below this level are not given the incentives to take advantage of such human engineering.
This may then ensure that everyone has sufficient height.
This in itself may be a reason not to pursue human engineering. This argument has been used against both climate adaptation and geoengineering. Some might also worry that, compared to other solutions, human engineering offers relatively few benefits for the costs involved.
This worry applies especially to human engineering solutions such as lowering birth-rates through cognitive enhancement or increasing altruism and empathy through oxytocin, which are relatively indirect means of mitigating climate change, in that they must pass through many steps in the causal chain before they can have an effect on the problem.
As a result, it might be thought that
using human engineering to tackle climate change is a poor use of
Discovering the extent to which human engineering - or any of the
other solution currently being considered - is worth pursuing is
largely an empirical challenge, and one that we are far more likely
to meet in a timely manner if we maintain open minds about which
solutions will be best.
In particular, who in their right mind would choose to make their children smaller? We are well aware that our proposal to encourage having smaller, but environmentally-friendlier human beings is prima facie outlandish, and we have made no attempt to avoid provoking this response.
There is a good reason for this, namely, we wish to highlight that examining intuitively absurd or apparently drastic ideas can be an important learning experience, and that failing to do so could result in our missing out on opportunities to address important, often urgent, issues. History is replete with examples of issues or ideas which, whilst widely supported or even invaluable now, were ridiculed and dismissed when they were first proposed.
In 1872, Pierre Pachet, a professor of physiology at Toulouse, dismissed Pasteur’s theory of germs as a ‘ridiculous fiction’.
An internal memo at Western Union in 1876 remarked that ‘this “telephone” has too many shortcomings to be seriously considered as a means of communication. The device is inherently of no value to us’. Lord Kelvin, the president of the Royal Society, claimed in 1895 that ‘heavier than air flying machines are impossible’.
In 1943, Thomas Watson, the chairman of IBM, doubted that the world could need any more than five computers. And only a few decades ago, those who worried about climate change - now widely recognized as one of the most pressing problems of our age - were frequently dismissed as ‘tree-huggers’.
The lesson here is that, whilst we may often be good
at judging which ideas are unworthy of pursuing, we are nevertheless
sometimes vulnerable to dismissing useful and valuable ideas.
There is something to this belief: in our society,
being tall is viewed as being advantageous. Studies show that women
find taller men more attractive than shorter men (Kurzban and Weeden
2005), and that taller people enjoy greater career success (Judge
and Cable 2004). Given this, it seems plausible that people will not
want to make themselves or their children shorter.
things that are freely available in society appeal to a limited few
and are given a wide berth by everyone else. Consider, for example,
tattoos, bungee jumping, and running marathons. In the case of
particular human engineering solutions with limited appeal, all
other things being equal, it seems that it is better that these
solutions are available and used by only a few than that they are
unavailable to all.
This could be because people’s attitudes about what is appealing can and do change, especially if there are ethical reasons for a particular type of intervention. For example, people’s attitudes towards vegetarianism have changed as a result of vegetarianism’s ethical status. People’s attitudes towards currently unappealing human engineering solutions may undergo a similar change as awareness spreads about the effects that these solutions could have on the problem of climate change.
Our attitudes about the extent to which certain qualities are appealing can also change with changes in the people around us.
A recent study shows that those who care about their weight are more likely to allow themselves to grow fatter when surrounded by overweight people than they are when surrounded by slim people (Blanchflower, Oswald et al., 2008).
This suggests that,
even if a relatively small number of people made their children
smaller, this might result in a reduction in the extent to which
having a certain minimum height is valued by others. With the right
incentives, such as tax breaks, those others might be willing to
have smaller children of their own.
Making our children smaller may be unappealing, but so is the prospect of having our children grow up in a world blighted by the environmental consequences of their ancestors’ choices and lifestyles.
To attempt to circumvent our preference for the current status quo, imagine that our pre-industrial ancestors are given a choice between,
It is not obvious that, to our pre-industrial ancestors, a) would stand out as the least appealing option.
In fact, it seems plausible that they might prefer a) to b)
or c), given that a) allows more people to live in a sustainable
world. In dismissing certain human engineering solutions as
unappealing, then, we should ensure that we are not thereby
implicitly endorsing a more familiar, but certainly no more
appealing, set of circumstances.
As we mentioned earlier, one way to reduce size and therefore carbon footprints is to reduce height.
But another way to reduce size is to reduce weight, which would presumably be less controversial. In general, there is no reason why it should not be possible to develop human engineering solutions that, as well as helping to fight climate change, are also highly appealing to individuals.
cognitive enhancements and pharmacological means of resisting meat
are likely to appeal to many people, since improved cognition and
the health benefits of vegetarianism are goods in themselves.
We argued that human engineering is potentially less risky than geoengineering and that it could make behavioral and market solutions more likely to succeed. We also considered some possible concerns regarding human engineering, and we suggested some lines of response to these concerns.
No doubt much more can be said for and against human engineering. In fact, our hope is that more will be said regarding it in the context of climate change.
Given that climate change is
likely to affect many aspects of life for all people around the
world, and given that behavioral and market solutions might not be
enough to mitigate climate change, we believe that human engineering
deserves to be considered and explored further in this debate.