"Just because Malthus wasn't right in his lifetime, that doesn't make him wrong. Malthus died in 1834: that's really not that long ago."
Malthus observed a historical phenomena that kept the population of Earth more-or-less constant since the agricultral revolution which in its time increased the population of the Earth by 2-3 orders of magnitude. Since the Industrial revolution and the era of economic growth all such predictions have been dramatically WRONG. Every time time humans appear to run up against a resource limitation, we've found ways around it. The most recent has been crude oil. Who talks about Peak-Oil now?
Our main problem now is that Fossil fuels are too cheap to give up without a global carbon tax.