"Homo sapiens will become extinct, perhaps within 100 years," he said. "A lot of other animals will, too. It's an irreversible situation. I think it's too late. I try not to express that because people are trying to do something, but they keep putting it off."
Although efforts are under way to mitigate the worst effects of overpopulation and climate change, Fenner believes it is futile, that our fate is sealed.
The world's population is forecast to balloon to 7 billion next year, putting a terrible strain on food and water supplies. So much so that Fenner predicts "food wars" in the coming decades as nations fight to secure dwindling supplies. Global droughts continue to ravage farmland, intensifying widespread malnutrition and poverty.
Climate change is a big driving factor behind his warning and, in Fenner's opinion, we've passed the point of no return. Although we have the scientific ability to tackle global problems, it's the lack of political will to do anything before the planet turns into a dust bowl that's the problem.
Although these warnings aren't without merit, I see Fenner's belief that all of mankind may not exist in a century to be overly pessimistic. It's not that I doubt the world will be a very different place in 100 years, it's just that he hasn't considered the technological factors of what makes humans human.
Granted, we're not very good at looking after our planet, and we are in a dire predicament, but thinking we'll be extinct in less than a century is a little over the top. There being a "collapse of civilization" or "rapid population decline" might be a better forecast.
Extinction occurs when every single member of a species dies, so unless a succession of global catastrophes (pandemics, runaway global warming, nuclear wars, collapse of resources, throw in an asteroid impact) happened at the same time, a small number of our descendants should still be able to eke out an existence in sheltered pockets around the planet.
In a paper published in the journal Futures last year, researchers approached the question: Human Extinction: How Could It Happen?
"The human race is unlikely to become extinct without a combination of difficult, severe and catastrophic events," said Tobin Lopes, of the University of Colorado Denver, in an interview with Discovery News. He added that his team "were very surprised about how difficult it was to come up with plausible scenarios in which the entire human race would become extinct."
Sure, we could be faced with a "perfect storm" of catastrophes leading to a mass extinction, but I think it will be more likely that we'll adapt quickly, using technology not necessarily to reverse the damage we have caused, but to support life in a hostile new world.
But this is as speculative as Fenner's gloomy forecast. I suspect the realities of living on a warming planet with a spiraling population and dwindling resources will remain unknown for some time yet. However, if our continuing abuse of resources continues at this rate unchecked, we can be anything but optimistic about our species' future.