BBC Science Focus: Mass extinction: Can we stop it?

02 October 2019
by Andy Ridgeway

BBC Science Focus' front page cover-story on Mass extinction: Can we stop it? quotes Lauren Holt and Simon Beard extensively.

"So in a future mass extinction, it’s probably the smaller generalists that will come out on top. But there’s a good chance that we humans will also have a say in what lives and dies, by pooling more effort and resources into saving certain species. “One of the things that will play a huge role in species’ survival chances is the extent to which they’re seen as important to human wellbeing,” says Dr Simon Beard, who is also a researcher at Cambridge’s CSER. “So we’re quite likely to see animals and plants such as sugarcane, cows and bananas continuing to dominate the global biosphere.”

The human factor

While there are parallels between previous mass extinctions and what is currently happening, there’s no escaping one key difference – these environmental changes have been brought about by human activity. That does mean, however, that there’s something we can do about it. For all its bad news, the UN’s Global Biodiversity Assessment says that it’s not too late to make a difference.

One thing previous mass extinctions tell us is that we should avoid just focusing on the atmospheric aspect of climate change, says Beard. “Mass extinctions have always been largely marine phenomena, since the majority of Earth’s biodiversity exists in the oceans. The most destructive changes we currently face may thus be the phenomena of declining levels of oxygen and increasing acidification of the Earth’s oceans. These are being driven by increases both in global temperature and atmospheric CO2.”

Here, a huge dip in the ground can be seen where the Arctic permafrost in Herschel Island, Canada, has melted © Getty Images
Then comes the awkward question of whether Homo sapiens would ultimately survive. Previous mass extinctions suggest that our survival depends on the answer to a key question – are we specialists or generalists? That’s not a straightforward question to answer.

We have become a successful species through immense individual specialisation – by becoming skilled at doing specific things, such as developing technology that allows us to fix the human body, or to grow food in hostile environments. “If we evaluate each individual’s chances of survival, we really look like toast,” says Beard. Collectively, however, we are generalists. “We can survive in space, in Antarctica, in deserts and underwater,” says Beard. “All we need is technology.” So that’s the paradox we will face if environmental conditions really turn nasty.

“Humanity is amazingly adaptable and creative,” says Beard. “It’s about having the curiosity to solve these problems. If we can do that, there’s a good chance of us making it through. But if we can’t, then there is a real chance of a total systems collapse. In that case, each of us is on our own. We can’t survive that way – it’s simply impossible.”

Our creativity needs to be applied carefully, though, says Lauren Holt. Take genetic engineering – techniques such as CRISPR gene editing have been suggested as a way to do everything from making coral more resistant to rising sea temperatures, to creating plants that suck more CO2 out of the atmosphere.

“I don’t think people fully understand the long-term implications of things like CRISPR technology on the stability of genomes,” says Holt. When an organism’s genome is unstable, it’s more likely to mutate, causing disease. “If we send organisms out into the world that have augmented ecology, we don’t know if that’s stable.”

As well as the safety of technological fixes for extinction, there are some wider questions to address, too. “Being an adaptable generalist rather than a vulnerable specialist is often referred to as ‘resilience’. but it’s important to accept that resilience is costly,” says Beard. “To be adaptable and resilient, we need to develop traits such as redundancy, so we have a backup system in place; preparedness, allocating resources to deal with the most unlikely of potential threats; and flexibility, not being too attached to how things currently are.”

The trouble is that businesses and governments are striving for efficiency rather than these other traits, says Beard.

So if we can take anything from previous mass extinctions, it’s that unity, cooperation and developing a little resilience will make us less like the dinosaurs and give us the best chance of fighting off mass extinction number six."

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