Shining through Solar, Ian McEwan's comedy treatment of energy and its crises, there are two views of why the environment is in a mess. The major diagnosis lies in the pathological incontinence of the novel's anti-hero Michael Beard: he simply cannot stop himself eating, fornicating, travelling.

At least he is helping to solve the problem by working on how to exploit quantum mechanisms in photosynthesis to make abundant hydrogen out of sunlight. Even his pride, deceit and theft are tools in the invisible hand that in the end help the environment. Beard's gluttony is sustainable because he is offering a physical fix to our clean energy problems he's working out. The physics may be nice, but the character or lifestyle are not – though they are apparently irresistible to women.

The second account of where things are wrong and how they might be fixed gives us a picture of a more attractive Beard in a privileged Arctic setting. He is cooped up with a bunch of bleeding heart environmental artists on a boat frozen into the ice around Spitzbergen.

In a moment of high comedy, McEwan deprives Beard of his priapism for a week. That does not banish all environmental problems , but they are changed by the brief relief from conquest: on the surface of the ice or the deck of the boat, artisitic society flourishes. Jesus, the Mallorcan sculptor, fashions animals out of ice with the care and attention to detail one would want from a benevolent creator. Beard has a moment of faux heroism he can happily claim as his. His masculinity is safe even if his penis is not.

Conversation is mostly good-natured, despite an enduring confusion from both the artists and the hard man of science about the difference between fact and value. When will the scientists see that relativism does indeed in some sense arise out of the naturalised world view of the post-Enlightenment, even if relativity is not the reference point for the moral "breakthrough"? Actually, moral relativism pre-dates relativity by about 150 years – look at Kiekegaard's "or", the selfish aesthete against whom the moralist can ultimately find no argument, only a life-defining choice. Or consider Hume's observation that reason will never lead me to prefer the pricking of my finger to the starvation of innumerable Indians. Humanity, seen under the macroscope as multiple locations of preference satisfaction, is a species in which there is no reason that compels behaviour. There are just causes of actions.

Yet Beard thinks he can be saved from this conclusion by asking for precision, and the artist thinks that the conclusion flows from the observation-dependence of the world. Neither is right, although the interests of each in his conclusion is clear: the scientist asks for corespondence to reality, and therefore precision, while the artist wants to change reality by making us see it as being like this or that – hence the hope that the world can be constructed by the way it is made to seem.

All is not utopian on the Arctic fjord, and the solution to environmental problems is not just a matter of the replacing of an obsession with consumption with an obsession with expression. The problem is the locker-room. Nature is harsh in the Arctic, and even the panophiles need utmost – and personal – protection against her. This comes in the form of skidoo suits and googles and heavy boots and layer upon layer of insulation. They all have to be kept in the dark underbelly of the boat. But the system of putting away each of our possessions in our particular place and respecting the property allocations of each breaks down almost immediately. This is the basic social metaphor of arctic life among the artists: even the simplest of allocation tasks breaks down.

Here is the account of the fall:

Four days ago, the room had started out in an orderly condition, with all gear hanging on or stowed below the numbered pegs. Finite resources, equally shared, in the golden age of not so long ago. Now it was a ruin [...] No one, he [Beard] thought, admiring his own generosity, had behaved badly, everyone, in the immediate circumstances, wanting to get out on the ice, had been entirely rational in 'discovering' their missing balaclava or glove in an unexpected spot. It was perverse or cynical of him to take pleasure in the thought, but he could not help himself. How were they to save the earth-assuming it needed saving, which he doubted-when it was so much larger than the boot room [...] But yes, he felt unusually warm towards human kind. He even thought that it could warm to him. Everyone, all of us individually facing oblivion, as a matter of course, and no one complaining much. But what about the general disgrace that was the boot room? Evidently a matter of human nature. And how were we going to learn about that? Science, of course, was fine, and who knew, art was too, but perhaps self-knowledge was beside the point. Boot rooms needed good systems so that flawed creatures could use them properly. Leave nothing, Beard decided, to science or art, or idealism. Only good laws would save the boot room. And citizens who respected the law."

With the return of Beard's sexual drive, of course, the first thing to go is any respect for the law. And there starts the novel's headlong rush into the world and mentality of endless clean energy, of abundance and consumption. The promise of plenty is enough to justify the abandonment of law and respectful citizens.

Despite Beard's boot-room revelation, the control of human drives – gluttony, sex, glory – continue to be the underlying determinants of whether the laws are good and the citizens are respectful. The simplicity of boot-room revelation does not survive the return of the human drives. Jesus the penguin sculptor and the other artists are sexual beings, but they are involved in a game where, whatever the boot-room problems, the boot-room is not where they spend their lives. Indeed, the worse that comes of the boot-room mess is that you end up wearing two left boots.

The world the novel goes on to explore is one that exists almost solely in the boot-room - it is about the brutal distribution of scarce sexual, comestible and progenital energies. Beard, who devotes much energy for the rest of the novel to a game of monopoly, had met, but forgotten in the arctic, the artist who had built a monopoly board the size of several football pitches - a version of the game that children can frolic around in and visit as they might have done in the Ideal Home Show. She is taken to court for breach of patent by the game developer. Beard himself gets tangled in patents, but his version of monopoly has nothing of the game. There is no redemption of monopoly through art, as there was in the Arctic. (There is, though, the faintest a hint of redemption through love).

So these are the alternative views of the environmental mess: the boot-room or the glutton. Will we save the environment by better management and finding new visions of the good life, as happens on the Arctic cruise?, or by finding a fix to allow our gluttony to continue unabated, letting Beards lead the way?

Accounts of where we are with the environment usually bring me back to this characterisation of the positions that we find:

Beard is in the bottom left corner: he works on technological fixes that allow his favoured life-style to be extended to all humanity. The novel is an excellent advertisement against that solution – not because the science isn't there, but because Beard's life is so unattractive. The food at the diner in Lordsburgh, New Mexico – so true to life, so comic – become the representation of heaven for this version of humanity. It is what this solution suggests about the nature human project that leads us to reject it.

The Arctic artists are in the top right quadrant - they want to devote their lives to creating meaning "outside the boot-locker" ("simplicitarians", in my shorthand). My trouble with the top-right quadrant is that the absence of technical fixes is a sort of crutch for a hair-shirt; no independent reason for preferring the simplicitarian life-style is offered. The attractive artist who enthuses that Beard is the only one who is doing something real is right, in a way. There is something ultimately passive about life in the top right quadrant.

Whatever turns out technologically, it seems to me that the best position to inhabit is the bottom right – to be a technology optimist who nevertheless sees the restraint of green lives as good in itself. If nothing else, it represents a low-risk maximin in the game we play with sceptics: even if nature lets us off, we will still have taken every advantage of the scare. McEwan may not be ignoring that quadrant entirely. It might well be the place inhabited by the real hero of the novel, the nerdy, sympathetic but hapless Tom Aldous.