There is no shortage of fantastical ways in which people imagine the end of humanity. Some of them lead to harmful behaviour. Putting aside cults, scare-mongering and general foolishness, however, the ultimate end of our species is a matter with which we need to engage seriously. And that is one of the reasons I think Kathleen Jamie’s On Rona is a small masterpiece: intentionally or otherwise, it allows for a meditation on human extinction. 
Our species has probably only come close to complete extinction once, in the remote past.  Given the stupendous numbers of us alive today and our energy and resourcefulness/ruthlessness, it can seem hard to believe that our end will ever actually come, barring some an unforeseen and/or uncontrollable cataclysm.  But while our future may be indefinite, it is surely not infinite. 
How do we relate to this apparently remote fact emotionally? How should we? Is it really so much harder for an individual to relate to than the fact of his/her own mortality? Perhaps we can go with Lawrence Krauss: 'We shouldn’t be depressed that we’ll disappear; we should be thrilled that we’re here right now.' 
Most of us would want the final end to be far away -- for the story of humanity to have a long way to go as yet. (For those of us who love our children, the idea that they or their successors will face tragedy and annihilation can seem unspeakably painful.) But would not an endless future, were it possible, be -- well -- rather boring? Even a very good story can get tedious if it goes on too long. There's a kind of incontinence to imagining an endless future.  The best stories by contrast, have an arc through time. (If we imagine trans-human or post-human stories we should do so with great caution and humility. )
We know enough to understand that in the near term the world needs mindfulness and cherishing. Some of the most relevant stories for the 21st century are, therefore, likely to centre on ways that we try to manage and control our appetites and fears, and on attempts to repair the world (and our ways) -- on efforts to slow the rate at which the whole universe of natural beings is turned into an undifferentiated 'standing reserve' of energy. 
The counter-desecration phrasebook suggested by Finlay Macleod and further sketched by Robert Macfarlane might help. Such a phrasebook would recall and revive some of the ways in which people comprehended the world before industrialization. It might contain equivalents to (for example) the Gaelic phrase Rionnach maoim, which means 'the shadows cast on moorland by cumulous clouds moving across the sky on a bright and windy day.' This 'unfeasible' phrasebook, writes Macfarlane, would stand, 'not as competitor to scientific knowledge and ecological analysis but as their supplement and ally.' 
It's a beautiful idea. And if it is 'unfeasible' then this does not have to be because of competition or contradiction between scientific and poetic ways of seeing. To take just one example, the fact that algae such as Chroomonas (and possibly other life forms) exploit quantum phenomena can only enhance our sense of wonder. No, the unfeasibility would have more to do with the likelihood that a mythic (dreamtime) state of mind (being) is hard for us to access in a sustained manner because we cannot pretend innocence of the history of our civilization.
1. That, at least, is one of the resonances I find in the piece. (Wiser readers may disagree!) Certainly, On Rona contains much else. Consider, for example:
I had the sensation I always have on Atlantic Islands, in summertime, when the clouds pass quickly and light glints on the sea -- a sense that the world is bringing itself into being moment by moment.This sentence captures very well something I tried to approach in Hypnagogia when I suggested that, though superficially stationary, an island can be like a boat and so resemble Nicholas Humphrey's image for consciousness itself. The shifting seas make more readily apparent the fourth dimension of time through which the island/boat travels (although if Julian Barbour is correct, time itself is an illusion).
2. The Toba catastrophe theory holds that between about 77,000 and 69,000 years ago the impacts of a volcanic super-eruption reduced humans to a small number of breeding pairs. Plagues and famines throughout subsequent human history, though catastrophic, have only extirpated humans locally. Perhaps the moment we came closest to extinction in recent years was the Cuban missile crisis, although it's likely that a remnant would have pulled through even the worst nuclear winter and repopulated the planet.
3. In With eyes wide shut, George Monbiot writes:
4. For Werner Hertzog that end is quite imaginable. Talking to Lawrence Krauss, Cormac McCarthy and Science Friday presenter Ira Flatow ( 8 April 2011), Herzog said, 'It is quite evident that humans as a species will vanish quite quickly - maybe two or three hundred years, maybe three thousand years, maybe thirty thousand years. It doesn’t make me nervous that soon we’ll have a planet that doesn’t contain human beings.' For more on Herzog and 'the necessary catastrophe' see Hari Kunzru's fine profile.We live in a dream world. With a small, rational part of the brain, we recognise that our existence is governed by material realities, and that, as those realities change, so will our lives. But underlying this awareness is the deep semi-consciousness that absorbs the moment in which we live, then generalises it, projecting our future lives as repeated instances of the present. This, not the superficial world of our reason, is our true reality. All that separates us from the indigenous people of Australia is that they recognise this and we do not.
5. Same source as footnote 4. Krauss's sentiment can be taken as a kind of species-wide positive thinking of the kind recommended by Steve Jobs for the individual (if not necessarily followed by the corporation he leads. [Added 30 April: see this too]). We need to recognize our limits in order to be human. Indeed, as Adam Gopnik writes, 'Perhaps our intelligence is not just ended by our mortality; to a great degree it is our mortality.' See also The Most Important Fact.
6. In a meditation on Crusoe's island, the novel, rare birds and the death of his friend David Foster Wallace, Jonathan Franzen notes boredom as a great enemy in his life. DFW was mentally ill, but boredom with self and with species is not necessarily insanity. Indefinite life extension seems deeply mistaken. As was recently written of Ray Kurzweil, 'One wonders how much of life he is missing by overthinking death.'
7. I think I share Giles Fraser's unease about Sam Harris's readiness to sacrifice humanity to the cause of a greater being. As Martin Rees and others have seen, perhaps more clearly than Harris, we have hardly begun to get our bearings on the non-human future. As Paul Broks wrote after interviewing Rees in 2010 :
We may, as a species, be suffering the cosmic equivalent of Anton’s syndrome, the neurological condition in which patients rendered totally blind by damage to the visual cortex believe they can see perfectly well. Perhaps the universe is an act of imagination. There’s no “perhaps” about it. The universe is an act of imagination, which is not to say there’s no “real world out there,” rather that our construction of it is shaped, and inescapably confined, by the powers of the human mind. Perhaps on a cosmic scale we are cosmically stupid.An open-ended possibilianism, a la David Eagleman may be the way to go.
8. 'Standing reserve' (Bestand) is from Martin Heidegger: The Question Concerning Technology (1949). The struggle to prevent mindless destruction may be lost much of the time, but that does not mean one should give up. As Cormac McCarthy put it in his conversation with Krauss and Hertzog, 'Just because I am pessimistic about a lot of things, that’s no reason to be miserable about them.' See also Towards a Green Stoic Philosophy.
9. A Counter Desecration Phrasebook by Robert Macfarlane appears in Towards Re-enchantment: Place and Its Meanings (2010) along with Kathleen Jamie's On Rona and essays by nine other writers.