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Spaceship Earth
In this extract taken from The Doomsday Book, the author, G. R. Taylor,
puts forward the idea that earth is like a spaceship with strictly limited resources. For millions of years in the past, man had regarded the earths
resources as illimitable; only recently has he begun to realize that they are not.
For millions of years we have known a world whose resources seemed
illimitable. However fast we cut down trees, nature unaided would replace
them. However many fish we took from the sea, nature would restock
it. However much sewage we dumped into the river, nature would purify
it, just as she would purify the air, however much smoke and fumes we
put into it. Today we have reached the stage of realizing that rivers can
be polluted past praying for, that seas can be overfished and the forests
must be managed and fostered if they are not to vanish.
But we still retain our primitive optimism about air and water. There
will always be enough rain falling from the skies to meet our needs. The
air can absorb all the filth we care to put in it. Still less do we worry whether
we could ever run short of oxygen. Surely there is air enough to breathe ?
Who ever asks where oxygen comes from, to begin with ? They should --
for we now consume about 10 per cent of all the atmospheric oxygen every
year, thanks to the many forms of combustion which destroy it: every
car, aircraft and power station destroys oxygen in quantities far greater
than men consume by breathing.
The fact is, we are just beginning to press up against the limits of the
earth's capacity. We begin to have to watch what we are doing to things
like water and oxygen, just as we have to watch whether we are overfishing
or overfelling. The realization has dawned that earth is a spaceship with
strictly limited resources. These resources must, in the long run, be
recycled, either by nature or by man. Just as the astronaut's urine
is purified to provide drinking water and just as his expired air is regenerated
to be breathed anew, so all the earth's resources must be recycled, sooner
or later. Up to now, the slow pace of nature's own recycling has served,
coupled with the fact that the "working capital" of already recycled material
was large. But the margins are getting smaller and if men, in ever larger numbers, are going to require ever larger quantities, the pace of recycling
will have to be artificially quickened.
All we have is a narrow band of usable atmosphere, no more than seven
miles (11.3 km) high, a thin crust of land, only one-eighth of the surface
of which is really suitable for people to live on, and a limited supply of
drinkable water, which we continually reuse. And in the earth, a capital
of fossil fuels and ores which we steadily run down, billions of times faster
than nature restores it. These resources are tied together in a complex
set of transactions. The air helps purify the water, the water irrigates the
plants, the plants help to renew the air.
We heedlessly intervene in these transactions. For instance, we cut
down the forests which transpire water and oxygen, we build dams and
pipelines which limit the movement of animals, we pave the earth and
build reservoirs, altering the water cycle. So far, nature has brushed off
these injuries as pinpricks. But now we are becoming so strong, so clever
and so numerous, that they are beginning to hurt.
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