Thanks Susan. You make several interesting points.
You are right to distinguish between reducing growth and reducing consumption. We can, in theory, have continued economic growth whilst reducing the rate at which we use up scarce resources. I wouldn’t say that growth is just an offshoot of population growth, but I should perhaps have distinguished between overall GDP and GDP per person.
In your second paragraph, you say “a zero growth economy means that there is no need for new technology.” But this doesn’t necessarily follow. You see; even if total output remains at a steady level from one year to the next, that doesn’t remotely mean that we can’t benefit from introducing new technologies. You can use that new technology to produce output more efficiently, with less damage to the environment. And new technology may enable us to replace existing goods and services with better goods and services. This means standards of living can go up, even without overall output going up.
In your third paragraph you say government wants growth “so that people can have jobs and pay taxes so we can have roads and hospitals and armies and other things that people want.” This is partially true, as growth can help to keep people in work and help the government to raise tax revenues. On the other hand however, it is perfectly possible to have plenty of jobs and plenty of roads and hospitals, even without economic growth. Indeed, if fewer resources were being wasted in the pursuit of needless economic growth, we might actually have more resources available for important projects such as building new hospitals.
Finally, you are right, of course, to be concerned about population growth, but as I say, you can have lots of technological advance even if economic growth is at zero.
Thanks again for your very thoughtful response! :)