I doubt any of these models will be accurate. But do they need to be? Either our technology will make our current lifestyles sustainable, or reality will catch up with us and cause much distress.
See also The Rational Optimist by Ridley, The Improving State of the World by Goklany, etc.
This is the road we are on: hideous mass death or utopia. I don't see a third possible outcome. Exponential stuff is like that-- the only potential outcomes are extreme.
Makes me wonder if the ancient religious visions -- e.g. Revelations -- about a 'heaven or hell' outcome aren't prescient bits of intuition about the fundamentally binary nature of human destiny. One way of thinking of it is that we're a cosmic civilization in its early startup phase... meaning that success or failure are the only two possible outcomes.