The annual investment forum in Tokyo of CLSA (Credit Lyonnais Securities Asia), a hugely influential group of fund managers, has heard a grim forecast from Dr Marc Faber, a market analyst with some success at forecasting crises. Universally pessimistic, he is dubbed "Dr Doom" by the industry. His forecast is that the US cannot service its growing mountain of debt, and that its debt repayments could hit 50 percent of tax revenues within 10 years. If this happens, he thinks the US will go bankrupt.

Dr Faber then ventures beyond market conditions to warn us of a coming "dirty war" which will shut down the internet and mobile phones, and see city water supplies being poisoned. He advises buying farmland and living rurally to escape the violence and biological attack which will afflict cities. He also suggests buying gold and precious metals "because they can be carried." In Asia he advises buying into agriculture and water treatment to play on future food and water shortages.

Chilling stuff, but will it happen? Doomsayers don't have a very good record. Humanity seems to muddle through despite the catastrophes so regularly predicted. Part of the reason is that we alter our behaviour to avoid them. We develop new technologies such as those which enabled the "green revolution" to avoid the threatened starvation. We will not all choke on the nightmare levels of pollution forecast because we are constantly developing ways of dealing with it and avoiding it. We haven't all died yet in a nuclear holocaust because we changed the way we behave once nuclear weapons entered the frame.

This is not to say Dr Faber is wrong – although I believe he is. It is just that he, like other doomspeakers, downplays what Julian Simon called "The Ultimate Resource," the creative ingenuity of humankind. Despite the gloomy forecasts that civilization would be wiped out by a new ice age, a population time bomb, a silent spring, or the depletion of scarce resources, we have proved quite adaptable and quite resourceful at dealing with problems.

I doubt Dr Faber's hedge fund audience will all rush take his advice. Maybe a few will hedge their bets by buying just a little farmland and just a little gold. The rest of us will probably bet on humanity again, rather than disaster.