Catastrophic Failure Of Earth's Global Systems Led To The Extinction Of The Dinosaurs – We May Yet Go The Same Way

TThe Extinction Of The Dinosaurs – We May Yet Go The Same Way iurii/Shutterstock

“Why did the dinosaurs die out?” The consensus, among palaeontologists and dinosaur crazy seven-year-olds alike, seems to be that about 66m years ago a 10km diameter asteroid crashed into what is now Central America. It raised up a cloud of dust and ash that spread across the upper atmosphere, blocking out the sun, cooling the Earth and destroying the ozone layer that protects life from harmful cosmic radiation.

These effects lasted more than a decade, devastating Earth’s plants and plankton. The devastation rapidly travelled up food chains, first killing off the large herbivores, who were unable to find enough food, and then the carnivores, who soon found themselves in the same position. A staggering 75% of species, including all “non-avian” dinosaurs, died out. This event, known as the end-Cretaceous mass extinction, is one of the “big five” such extinctions known from the past 500m years of Earth’s history.

PENDING PERMISSION. Sam Noble Museum, Oklahoma University

But this was not the only dramatic event to coincide with the death of the dinosaurs. At around the same time, in central India, a truly colossal series of volcanoes were spewing out over a million cubic kilometres of lava together with sulphur and carbon dioxide that changed the climate and caused global acid rain. Meanwhile, a slowing of undersea tectonic activity led to one of the most rapid periods of falling sea levels in the history of the planet, devastating coastal ecosystems.

This has led to some pretty heated debates about what “really” killed the dinosaurs, especially as there have been times when similarly dramatic events occurred without seeming to cause nearly so much harm.

One of the ‘big five’ extinctions. AuntSpray/Shutterstock

Perhaps this is the wrong question to ask.

Profound, complex, interconnected change

Growing evidence now suggests that these events were interconnected and that the dinosaurs’ 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.

Yet, the biggest of all mass extinction events, the “Great Dying” at the end of the Permian period 250m years ago – which killed 90% of all species on Earth – looks even more complex. No fewer than seven potentially catastrophic events are associated with this period in geological history. These include the evolution of new strains of microorganism, an asteroid impact, and a humongous area of volcanic activity in present day Siberia that erupted for a million years.

But the greatest changes may have taken place in the Earth’s oceans. There were large-scale emissions of methane from the ocean floor,the stagnation of ocean currents, increased levels of sulphur dioxide causing phytoplankton death, and declining levels of oxygen.

With so much going on, it is less surprising that 90% of all species died out than that 10% survived.

Precarious times

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.

From looking at the historical, and the geological, record it becomes clear that such systems can easily pass through phase changes in which a previously stable system quickly, and sometimes irrevocably, changes into a chaotic one. Scientists have already identified how this might occur in relation to phenomena such as climatic tipping points (where climate change becomes self-sustaining, rather than being simply “man-made”), ecosystem collapse (where the loss of a few key species can cause whole ecosystems to disappear), and hyperinflation (where previously stable economic institutions cease functioning and money loses its value).

Climatic tipping point? Roschetzky Photography/Shutterstock

Another thing that we learn from these past events is that there is no law of nature that prevents such phase changes becoming global in scope or catastrophic in nature. If pushed far enough, global systems can evidently collapse into a death-spiral, whereby the damage to one species, ecosystem or environmental process causes problems for others, creating positive feedback that accelerates change and makes it self-sustaining.

Indeed, while the popular “Gaia hypothesis” suggests that global systems act to promote the overall stability of our planet, there is no conclusive evidence that the biosphere adjusts to changes to support the continuation of complex life. Indeed, it was recently suggested that one reason life may be rare on other planets is that its emergence often pushes planetary systems away from the conditions necessary for its continued existence. It is not impossible that this could still happen on Earth.

Profound change. FloridaStock/Shutterstock

Nor may the systems we ourselves have designed be any less fragile in this respect. Indeed, many of our institutions have shown themselves to be almost entirely unconcerned with human well-being; so long as they can serve the interests of short-term profit maximisation, voter turnout and other, ultimately useless, goals.

Yet, it might not be all bad news for humanity. Some theorists suggest that the catastrophic effects of a mass extinction tend to sweep away the highly adapted specialists of the era, and allow more flexible generalists to survive and eventually flourish into new forms. So perhaps we can take comfort from the fact that humans have showed themselves to be the ultimate generalists, adapting to survive, though not always thrive, in every habitat on Earth, and even in outer space.

But we should also reflect on the fact that most of this flexibility flows not from our biology but from the technologies we have created. Not only are these the very technologies that are leading us to push global systems as far as we have, but they are rapidly passing out of the realms of human comprehension in their complexity and sophistication. Indeed, it now requires immense individual knowledge to use and maintain them, making each of us, individually, just the sort of adapted specialists most vulnerable in a mass extinction event – something that may not be quite such good news after all.The Conversation

About The Author

Simon Beard, Senior Research Associate, Centre for the Study of Existential Risk, University of Cambridge; Lauren Holt, Research Associate, Centre for the Study of Existential Risk, University of Cambridge, and Paul Upchurch, Professor of Palaeobiology, UCL

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Related Books

Climate Change: What Everyone Needs to Know

by Joseph Romm
0190866101The essential primer on what will be the defining issue of our time, Climate Change: What Everyone Needs to Know® is a clear-eyed overview of the science, conflicts, and implications of our warming planet. From Joseph Romm, Chief Science Advisor for National Geographic's Years of Living Dangerously series and one of Rolling Stone's "100 people who are changing America," Climate Change offers user-friendly, scientifically rigorous answers to the most difficult (and commonly politicized) questions surrounding what climatologist Lonnie Thompson has deemed "a clear and present danger to civilization.". Available On Amazon

Climate Change: The Science of Global Warming and Our Energy Future second edition Edition

by Jason Smerdon
0231172834This second edition of Climate Change is an accessible and comprehensive guide to the science behind global warming. Exquisitely illustrated, the text is geared toward students at a variety of levels. Edmond A. Mathez and Jason E. Smerdon provide a broad, informative introduction to the science that underlies our understanding of the climate system and the effects of human activity on the warming of our planet.Mathez and Smerdon describe the roles that the atmosphere and ocean play in our climate, introduce the concept of radiation balance, and explain climate changes that occurred in the past. They also detail the human activities that influence the climate, such as greenhouse gas and aerosol emissions and deforestation, as well as the effects of natural phenomena.  Available On Amazon

The Science of Climate Change: A Hands-On Course

by Blair Lee, Alina Bachmann
194747300XThe Science of Climate Change: A Hands-On Course uses text and eighteen hands-on activities to explain and teach the science of global warming and climate change, how humans are responsible, and what can be done to slow or stop the rate of global warming and climate change. This book is a complete, comprehensive guide to an essential environmental topic. Subjects covered in this book include: how molecules transfer energy from the sun to warm the atmosphere, greenhouse gases, the greenhouse effect, global warming, the Industrial Revolution, the combustion reaction, feedback loops, the relationship between weather and climate, climate change, carbon sinks, extinction, carbon footprint, recycling, and alternative energy. Available On Amazon

From The Publisher:
Purchases on Amazon go to defray the cost of bringing you InnerSelf.comelf.com, MightyNatural.com, and ClimateImpactNews.com at no cost and without advertisers that track your browsing habits. Even if you click on a link but don't buy these selected products, anything else you buy in that same visit on Amazon pays us a small commission. There is no additional cost to you, so please contribute to the effort. You can also use this link to use to Amazon at any time so you can help support our efforts.

 

enafarzh-CNzh-TWnltlfrdehiiditjakomsfaptruesswsvthtrurvi

EVIDENCE

The US Defense Department Is Worried About Climate Change – And Also A Huge Carbon Emitter
The US Defense Department Is Worried About Climate Change – And Also A Huge Carbon Emitter
by Neta C. Crawford
Scientists and security analysts have warned for more than a decade that global warming is a potential national…
Northern Hemisphere’s Extreme Heatwave In 2018 Impossible Without Climate Change
Northern Hemisphere’s Extreme Heatwave In 2018 Impossible Without Climate Change
by Tom Prater
Last summer’s unprecedented northern-hemisphere heatwave “could not have occurred without human-induced climate…
The Methane Detectives: On the Trail of a Global Warming Mystery
The Methane Detectives: On the Trail of a Global Warming Mystery
by Jonathan Mingle
The amount of heat-trapping methane in the atmosphere seemed to be leveling off when, in 2007, it began rising again…
Arctic sea ice loss affects the jet stream
Arctic Sea Ice Loss Affects The Jet Stream
by Tim Radford
The jet stream affects northern hemisphere climates. And global warming affects the behaviour of the jet stream.…
The Ocean Captures Gigatonnes Of Our CO2 Emissions
The Ocean Captures Gigatonnes Of Our CO2 Emissions
by ETH Zurich
Researchers have determined how much human-made CO2 emissions the ocean took up between 1994 and 2007.
Bleaching Has Struck The Southernmost Coral Reef In The World
Bleaching Has Struck The Southernmost Coral Reef In The World
by Tess Moriarty, et al
This month corals in Lord Howe Island Marine Park began showing signs of bleaching. The 145,000 hectare marine park…
File 20180823 149478 1piuumq.jpg?ixlib=rb 1.1
Why It's So Hard To Detect The Fingerprints Of Global Warming On Monsoon Rains
by Jonathan Eden
The devastating floods in the Indian state of Kerala are a stark reminder of the vulnerability of the world’s most…
How Well Have Climate Models Projected Global Warming?
How Well Have Climate Models Projected Global Warming?
by Zeke Hausfather, Carbon Brief
Scientists have been making projections of future global warming using climate models of increasing complexity for the…

LATEST VIDEOS

Deep Sea Carbon Reservoirs Once Superheated The Earth – Could It Happen Again?
Deep Sea Carbon Reservoirs Once Superheated The Earth – Could It Happen Again?
by Lowell D. Stott
As concern grows over human-induced climate change, many scientists are looking back through Earth’s history to events…
Climate Change Alters What's Possible In Restoring Florida's Everglades
Climate Change Alters What's Possible In Restoring Florida's Everglades
by Gardner William Nuttle
The Everglades are a vast network of subtropical freshwater wetland and estuarine ecosystems that once spanned the…
The US Defense Department Is Worried About Climate Change – And Also A Huge Carbon Emitter
The US Defense Department Is Worried About Climate Change – And Also A Huge Carbon Emitter
by Neta C. Crawford
Scientists and security analysts have warned for more than a decade that global warming is a potential national…
Blue Ocean Event : Game Over?
by Just Have a Think
A Blue Ocean Event, or Ice-Free Arctic, is the source of almost fever pitch speculation in the climate science world.…
Climate Change - The Facts by Sir David Attenborough
by David Attenborough, BBC
After one of the hottest years on record, Sir David Attenborough looks at the science of climate change and potential…
Why it’s time to think about human extinction
by Kerwin Rae
After listening to this ep with Dr David Suzuki, you’ll never be the same again. The environmentalist, activist,…
Record Temperatures 20-25C Above Norm in far North
by Paul Beckwith
The Northwest Territories of Canada had March temperatures above 20C for the first time (hit 21.6C or 71F); breaking…
Why New CO₂ Capture Technology Is Not The Magic Bullet Against Climate Change
Why New CO₂ Capture Technology Is Not The Magic Bullet Against Climate Change
by Chris Hawes
According to a recent major UN report, if we are to limit temperature rise to 1.5 °C and prevent the most catastrophic…

LATEST ARTICLES

Limiting Warming To 1.5C Could Prevent Thousands Of Heat Deaths In US Cities
Limiting Warming To 1.5C Could Prevent Thousands Of Heat Deaths In US Cities
by Thomas Harrisson
Holding global temperature rise to 1.5C above pre-industrial levels, rather than 2C or 3C, could help prevent thousands…
Healthcare In World’s Largest Economies ‘accounts For 4%’ Of Global Emissions
Healthcare In World’s Largest Economies ‘accounts For 4%’ Of Global Emissions
by Josh Gabbatiss
CO2 emissions from healthcare in the world’s largest economies account for about 5% of their national carbon…
File 20180124 72597 1twk9y1.png?ixlib=rb 1.1
Biomining The Elements Of The Future
by Marcos Voutsinos, University of Melbourne
Biomining is the kind of technique promised by science fiction: a vast tank filled with microorganisms that leach metal…
What George Bush And The Neocons Can Teach Us About Fighting Climate Change
What George Bush And The Neocons Can Teach Us About Fighting Climate Change
by Ash Murphy
Be under no illusion, the world is losing the fight against climate change. The amount of CO₂ in the atmosphere…
Deep Sea Carbon Reservoirs Once Superheated The Earth – Could It Happen Again?
Deep Sea Carbon Reservoirs Once Superheated The Earth – Could It Happen Again?
by Lowell D. Stott
As concern grows over human-induced climate change, many scientists are looking back through Earth’s history to events…
Britain Is In The Middle Of A Drought – So How Come There's Flooding?
Britain Is In The Middle Of A Drought – So How Come There's Flooding?
by Hannah Cloke
Parts of the UK had more than a month’s rain in one day on Monday June 10. More rain on the following Tuesday,…
How To Feed A Growing Population Healthy Food Without Ruining The Planet
How To Feed A Growing Population Healthy Food Without Ruining The Planet
by Alessandro R Demaio, et al
If we’re serious about feeding the world’s growing population healthy food, and not ruining the planet, we need to get…
How To Get A High-renewable Electric Grid
How To Get A Highly-Renewable Electric Grid
by Richard Perez and Karl R. Rabago
The famous inventor Edwin Land said, “It’s not that we need new ideas, but we need to stop having old ideas.” He seemed…