Andrew Knoll: ‘Mass extinction is accurate description of how world is changing now’

Knoll, a Harvard University paleontologist. has been working with biologists to try to put into perspective what he called today’s catastrophic loss of biodiversity. Up to 50% of species on Earth are predicted to disappear within the next 100 years.

Andrew Knoll: Although in the geologic sense we know that given several million years after a mass extinction diversity rebounds, that’s not comforting if you’re really thinking about your great grandchildren.

Andrew Knoll, a Harvard University paleontologist. has been working with biologists to try to put into perspective what he called today’s catastrophic loss of biodiversity. Up to 50% of species on Earth are predicted to disappear within the next 100 years.

Andrew Knoll: A mass extinction is simply defined as an unusually large loss of biodiversity over a very short time interval. I think that’s an accurate description of the way our world is changing today.

Knoll talked about another extinction event – the one that wiped out the dinosaurs 65 million years ago.

Andrew Knoll: Essentially there was a very bad Thursday, when a meteor hits the planet, there is lots of short term perturbation of environments, it has huge and lasting consequences. But very soon after that, the planet started to heal and diversity started to radiate.

Knoll thinks today’s extinctions will likely play out differently, because human-induced climate change and habitat destruction won’t resolve as quickly.

Andrew Knoll: Today, since the disturbance is basically us, and our lifestyles, essentially the planet gets bad in the sense of being challenging for many species, but then it stays bad. It’s very hard to see the prospects for a healing or resuscitation of diversity.

He thinks today’s loss of biodiversity will change the way the world works, but that humans will still be around 500 years from now.

Andrew Knoll: To the extent that that optimism proves justified, it’s going to be because talented people take up the challenge to rethink energy, rethink agriculture, rethink, basically, the way we live. I’m much worried about populations essentially crashing to zero and ecosystems essentially not functioning in terms of retaining their nutrients the way that they might. So I’m not worried about the rise of evolutionary monsters. Quite the contrary, I’m worried about the loss of the familiar.

He also talked about ocean acidification, which is acknowledged by many experts to be a consequence of excessive carbon dioxide – a greenhouse gas – in our atmosphere.

Andrew Knoll: I’ve been working with people who are interested in ocean acidification because that is a process whose fingerprint we can see in the past. And when we look back at some geologic or historic intervals when we think there was rapid change in CO2 and rapid change in the oceans we see that there was a very selective extinction of organisms. So we can actually go to biologists and say, you know, if I were you, I might do some physiological experiments on this kind of organism.

Beth Lebwohl