The fun part is that Slashdot tagged it 'troll'. Which I personally find accurate: when I contributed, I felt I was partially trolling.
The basic argument is that climate change and many other environmental problems have upstream and downstream solutions. For example, 1) human consumption leads to 2) a demand for production and energy, which leads to 3) industry, which leads to 4) greenhouse gas emissions, which lead to 5) planetary heating, which leads to 6) bad consequences. One solution might be to try to make less emissive industry (fix the 3-4 link). Another might be to remove greenhouse gases from the atmosphere (reduce 4), geoengineering that cools the planet (reduce 5) or adapt to a changed world (handle 6). The latter are downstream solutions.
When geoengineering is suggested many people think it is better to use an upstream solution for a variety of reasons (controllability, scepticism of technological fixes etc). Consuming less would be really upstream (ignoring the practical problems of actually doing it to the extent necessary, which are pretty major, and the countervailing aspects of human psychology). But if it is better to have upstream solutions, why not go for cause 0, human desires for various things? If people do not want meat, plenty of grassland could be reforested and emissions reduced. If people want to have fewer children, resources become less scarce and so on. If people are smaller, they need less resources.
So we argue that it might be a good idea to look at reengineering humans to be green. Obviously we can change ourselves through culture and rational convincing... to some extent. But it is tough to change lifestyle this way. So might there be tricks to modify ourselves in order to better behave in ways we want to want. Biological means to make our second order desires dominate first order desires.
The methods we mention are mostly examples and likely *far* too wussy to amount to much. But there might be better methods if we were to investigate them properly. Of course, in the long run I think the real sustainable choice is to become postbiological. But that is a bit further away. This is also why I doubt genetic engineering is going to be that effective: it takes so long time, parents will be very cautious about it, and the things that can be done ethically are fairly limited.
To some degree I think our paper is green design fiction of the kind I criticised earlier. But I suspect that the ethical irritant effect of bioengineering humans might be enough to trigger some thinking about to what lengths we actually do want to go about fixing the environment. Sometimes downstream solutions might be more ethical and humane. But we should not imagine that our biological nature is exempt from being part of a potential solution.