So I rewatched Silent Running
a couple of weeks ago, on Eureka's fine Blu-Ray reissue. The flaws are still there - notably, of course, and by the way for those who care SPOILER, the ridiculous length of time a crusading botanist takes to realise that plants fail to thrive without adequate illumination. But the spaceships and their geodesic domes look as lovely as ever (director Douglas Trumbull was of course one of the special photographic effects supervisors
on 2001: A Space Odyssey
), Bruce Dern's manic yet sympathetic performance is still terrific, the robots are even cuter than I remember, and its take-home message that the human species shouldn't trust capitalism to look after nature is still urgent.
was released in 1972. A couple of years before, I first heard Joni Mitchell's 'Big Yellow Taxi', which struck me with such a thrill that I still remember the circumstances: sitting with my family at the square table, with its green oil cloth cover, in the kitchen of my great-aunt's boarding house in Bognor Regis, where we regularly stayed for our summer holidays. It was mid-August, 1970. A few days later, little further down the south coast, Joni Mitchell would close her set at the Isle of Wight Festival with the song. I was 15, keen on natural history. I knew about the damage cause by the Torrey Canyon disaster; I'd read Harry Harrison's Make Room! Make Room!
, John Brunner's The Sheep Look Up
, and other science-fictional Awful Warnings; there'd been the First Earth Day earlier that year, calling for greater awareness of damage to the environment and squandering of the planet's resources. And here was a sprightly pop song with the same message. 'Don't it always seem to go, That you don't know what you've got, Till it's gone.' Ecological disaster was very much in the air back then. We were beginning to realise that everything on the planet is connected to everything else.
, in its title, and 'Big Yellow Taxi', in its lyrics ('Hey farmer farmer, put away that DDT now'), pay homage to Rachel Carson's Silent Spring
, which documented the catastrophic effects of the indiscriminate use of pesticides on the environment. A little over fifty years after its publication, the bleak future suggested by the title of Carson's book is coming true: a paper just published
provides strong evidence that Earth's sixth mass extinction event really is under way, driven not by geological or astronomical disasters, but by human activity.
The authors of the paper used fossil records to calculate a background extinction rate, and compared it with an estimate of what has been lost since 1900. In that time, nine vertebrate species should have become extinct by natural causes; instead, recorded extinctions are occurring at a hundred times the expected level, faster than at any time since the demise of the dinosaurs. Similar calculations have been criticised for overestimating differences from the background rate. But this new study uses highly conservative figures; although its conclusions are stark, the authors point out that actual rates of loss could be higher. As in the case of the Eastern Cougar, just now listed as extinct
, it can take many decades between the last sighting and the official declaration that a species is gone.
It's been known for some time that a catastrophic level of extinction is imminent, driven by the expansion of the human race and our increasing utilisation of the Earth's resources. We account for one third of the total mass of all land vertebrates
; our food animals make up much of the rest; wild animals account for just 5% total mass. Our cities and agriculture take up increasing amounts of land area, destroying natural habitats; we consume about forty per cent of the world's annual photosynthetic output; the carbon dioxide produced by our burning of fossil plants is irreversibly changing the planet's climate.
Not only are we at risk of losing large numbers of iconic and charismatic species, from tigers to Emperor penguins. We're also playing a giant and potentially lethal game of Jenga with the environment. Remove a keystone species, or reduce its numbers so that it's no longer influential, and the consequences ramify in unexpected and sometimes catastrophic ways. In the eighteenth century, for instance, the population of sea
otters along the Californian coast was enormously reduced by the fur
trade. Sea otters eat sea urchins, and in the absence of otters the
urchins multiplied, gnawing away the holdfasts of giant kelp and
destroying vast kelp forests where hundreds of other species lived. Multiply that by a hundred instances over the next few decades. That's where we're going if we aren't careful, because everything's connected.
otters were saved from extinction by conservation measures introduced in
the early twentieth century and the kelp forests have partly returned. And there's a consensus amongst scientists that it's possible to slow the current rate of loss and destruction. Partly, at least. But if action isn't taken, we will have to choose what to save and what to let go. Ecosystems will be regulated or replaced. Intervention will become the norm. Charismatic species will be tagged, monitored by drones, tailored so that they can live in cities or farmland. The last of Nature will be subsumed into the technosphere, confined to refugia. Gardens, parks, zoos. Biomes will be sheltered under geodesic domes, nurtured by cute robots. Trees will be preserved in tree museums. Don't it always seem to go.