The Atlantic's Noah Smith has written on whether capitalism actually does require growth to continue. He argues:
Looking at history, we see that the biggest challenges to capitalism actually came during times of rapid growth. The early 20th Century was the heyday of communism, anarchism, and socialism. But this was a time of immense growth, technological progress, and increased material standards of living. It seems possible that those alternatives to capitalism gained popularity precisely because rapid growth disrupted the stable social systems that had been in place before the Industrial Revolution.
Clearly there's something problematic in that analysis; the "stable social systems" in place before the Industrial Revolution had very little in common with capitalism as we know it today. It may well be the case that the age the joint-stock company didn't require growth in the same way that modern financial capitalism does.
Smith does, however, argue that finance doesn't require growth either, because interest comes not just from an expectation of growth but also the value of consumption smoothing. That is, people will put up with having less money in the future in order to have income now, and interest is a reflection of that.
But the whole argument is rather a moot point, either way, because it's so frequently brought up in the context of a second claim: that growth requires exploitation of resources, and that if we desire an economy which doesn't carry on tearing up the planet, we need to accept that that economy will be "steady state".
There is clearly a grain of truth here. Famously, the history of America can be described, in economic terms, as a country continually dealing with financial issues by physically growing; first expanding south, then west, and then eventually overseas in the form of the pseudo-protectorates the US now runs. And an end to resource extraction would definitely hit growth rates enormously, if for no other reason than that it would require the world's economy to be completely retooled around renewable energy and recycling usable material from waste, which wouldn't happen painlessly.
But it's simply not true to say that growth can only come from increased abuse of the environment. My favourite illustration of the falsehood comes from a two-year-old piece by Alexis Madrigal:
Imagine you've got a shiny computer that is identical to a Macbook Air, except that it has the energy efficiency of a machine from 20 years ago. That computer would use so much power that you'd get a mere 2.5 seconds of battery life out of the Air's 50 watt-hour battery instead of the seven hours that the Air actually gets. That is to say, you'd need 10,000 Air batteries to run our hypothetical machine for seven hours. There's no way you'd fit a beast like that into a slim mailing envelope.
That, right there, is growth. For the energy cost of running one laptop twenty years ago, you can now run 10,000. That's an annual growth rate of just under 60 per cent.
Clearly, energy efficiency in portable computers over the last 20 years is one of the most rapid measurable increases in technology ever, but nonetheless, it puts paid to the idea that all growth can be is increasingly extractive.
We should be planning for an economy which takes only memories and leaves only footprints — but that's not the same as planning for an economy with no growth. Though George Osborne might wish to convince you otherwise, that would be an unnecessary disaster for all concerned.