Conversation: global systems and dinosaur extinction

29 March 2019
by Simon Beard, Lauren Holt, Paul Upchurch

CSER researchers published a Conversation article arguing that catastrophic failure of Earth’s global systems led to the extinction of the dinosaurs – and we may yet go the same way.

"Growing evidence now suggests that the dinosaur’s extinction cannot be explained as a simple process during which one “bad thing” fell out of a clear blue sky and everything died. Rather, it involved profound, complex and interconnected changes to the global systems that support life.

For instance, the late cretaceous period saw gradual and subtle restructuring of terrestrial ecosystems, making them more vulnerable to catastrophic collapse. Such restructuring was potentially brought about by multiple evolutionary and ecological changes related to climate change, the increasing dominance of flowering plants, and fluctuations in the diversity and abundance of particular dinosaur groups.

Nor is this complexity an unusual feature of mass extinctions. Across all five of Earth’s devastating global catastrophes, there is a veritable whodunit of possible causes. These include asteroids, volcanoes, climate change (both warming and cooling), the evolution of new species such as deep-rooted plants that turned bare rock into rich soil for the first time, and even the effects of nearby exploding stars.

[...]

What does this imply about our current age, which many now see as constituting a “sixth” mass extinction11? At the Centre for the Study of Existential Risk at Cambridge University, we often come up against the problem of today’s “unprecedented” global threats. Some of these, like the threats from nuclear weapons or Artificial Intelligence, may seem akin to asteroids falling out of the sky, and we are often asked which most worry us. One thing we can take away from the study of previous mass extinctions is that this question may be misplaced.

Humanity lives far more precariously than we think, dependent upon a great many global systems, from the environment that provides us with food, water, clean air and energy to the global economy that supplies goods and services where we want them and when we want them, often on a “just in time” basis."

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