The rejoinder to Bartlett and others like him is that technology will overcome any limits, and that we'll use substitutes for resources that run low. It's hard to imagine what might be a good substitute for uncontaminated, potable water; but, in the cornucopian's mind anything is possible. It's also hard to imagine a modern technical society without metals. But, we'll think of something, right? However, please don't say that that something is made out of materials derived from oil, natural gas or coal which are also finite.
The problems posed by exponential growth mean we'll have to think of "something" at increasingly short intervals given the ever rising rates of consumption and the broad range of finite materials we depend on--especially fossil fuels (oil, natural gas, coal) and much of the periodic table of elements including the usual suspects such as iron, copper, aluminum, zinc, silver, platinum, and uranium and the more exotic ones such as lithium, titanium, the so-called rare earth elements, and helium.
It's not just one substitute we'll have to find. And, we may be faced with having to find many all at once. The idea that technological innovation will always and everywhere stay ahead of an ever increasing rate of depletion may be true or not true. But we cannot know this ahead of time. - Kurt Cobb