Posted tagged ‘extinction’

Are we safe? Maybe, sort of…

March 27, 2012

“Are we safe?”, I was asked last week. The question was a discussion starter for an enjoyable panel which closed the Oxford Literary Festival’s Saturday afternoon look at science and the future – an event which ranged from cosmology to climate change.

The event was a conversation (with the always apocalyptically cheerful Anders Sandberg and writer Sara Wheeler)– generally a  better way of doing these things than getting panellists to speak separately. But, in the way of conversation, it provoked some second thoughts. So here are a few of the things I said, or thought I might have said, in some sort of order.

Are we safe?

No, of course not. We are mortal. We live in a peculiarly fortunate culture where, for quite long spells, many of us can forget about this. But, in Larkinesque fashion, it is a truth which always comes back.

But what of existential risk – in the sense of threats to the whole of humanity? Individual responses to this tend, in my view, to be determined by a combination of temperament and circumstance.

How so? Well, we are talking about the probability of lots of inevitable individual deaths happening all at once, adding up to the death of a species (ours), or extinction.

We do have some information that bears on that, but not enough to give a very clear answer on how likely it is. So the way we feel about it tends to reflect our intuition about some related questions: is human life fragile or robust, the cosmos friendly or unfriendly, hospitable or inhospitable?

At the moment, we can find reasons for answering that question about equally convincingly either way.

Good things: the constants of the universe are tuned to just the right combination which allows life to exist. (The Goldilocks principle). We seem to live in a cosmos which is disposed to allow the emergence of  complexity – in ever more wondrous forms. In some sense, perhaps, we are meant to be here. In Stuart Kauffman’s phrase, we’re at home in the universe.

Notsogood: one of the main processes which allows that complexity to emerge – natural selection – is rather scary when you look at how it works. I don’t mean Nature red in tooth and claw: evolution has a place for co-operation as well as competition. However, although natural selection sounds neutral, or even benign, the agent of selection is death – of individuals and, on the larger scale, the death of species. Extinction is just what happens to species, in the end. Endurance beyond a few tens of millions of years is very much the exception, and those species that have lasted for a few hundred millions years are heroic survivors. (Afterthought to the afterthought – I wonder if that is true if you include the microbial world, where the concept of species is in any case pretty hard to apply…)

Of course, a species can leave descendents on the path to extinction, as we may do. But in its original form it has still quit the scene. At our current point, where culture – in the shape of technology – is a more powerful evolutionary force than natural selection, that seems an increasingly likely outcome. Whether you terribly much mind that idea depends on whether you think Homo sapiens in our present form are such an adornment to the cosmos we ought to be around for ever, or if it is OK we are just a stage on the way to something else. That something has a post-human form we cannot quite define. But we’ll know it when we see it.

Aside from how evolution actually works, other features of the cosmos suggest that a middle of the road position is justifiable. The universe is more or less hospitable, but risky.

It is interesting to contemplate the latest results on star systems with planets, for example. Amazingly, our observations now have such fine resolution that we can detect planets orbiting distant stars, and not just gas giants but even smaller, possibly Earth-like ones. It looks more and more as if there are an enormous number of solar systems out there, and a heck of a lot of Earth like planets. That surely makes it more likely that there is complex life spread, however thinly, through the galaxy, maybe all galaxies in the observable universe.

Then consider gamma ray bursts. We don’t understand them very well, but we do know by observation that, occasionally, there are absolutely enormous energy releases, with no warning that we know how to register, that rip through large regions of space.

So if life, even intelligent life, is ubiquitous, every now and again one of these gamma bursts takes out a civilization. (Oliver Morton wrote about this eloquently in Prospect a decade or so ago, when the search for extra-solar planets was less well on than it is now.) The universe, if you like, is welcoming to life, then takes random shots at it for sport.

Against that background, the risks we face on Earth at the moment seem relatively manageable. Bad things will happen. Perfectly terrible things may happen, in the future as in the past. A person who predicted that the sky would fall 65 million years ago, before an asteroid impact caused a mass extinction, would have been right. A person who predicted crop failure, pandemic and the death of between a third and a half of the population of Europe in the 14th century would have been right. Those who foresaw a a terrible conflict in Europe in the late 1930s (read Louis MacNiece’s Autumn journal for the atmosphere) were correct.

On the other hand, plenty of possible dire events did not come to pass. No nuclear holocaust (yet). No billions starving before 2000, pace Professor Ehrlich.

So, there will be good and bad. But, assuming gamma ray bursts are not coming our way, the end of humanity is not coming any time soon, probably…

(Thanks to Georgina Ferry for the invitation to Oxford.)