Scientist Predicts "Mass Extinction" Caused by Breach of Carbon Threshold

The research is based on geological records that provide a window into CO2 levels from millions of years ago.
Chris Young

MIT scientist Daniel Rothman has released new findings that suggest the Earth might be on course for a "mass extinction" event if we surpass a threshold of carbon dioxide in our oceans.

The current rate at which carbon dioxide is entering the oceans, he says, could cause an unstoppable cascade of chemical feedbacks. Rothman claims that we may be worryingly "close to this critical threshold."


Chemical feedback

Rothman, a professor of geophysics and co-director of the Lorenz Center in MIT’s Department of Earth, Atmospheric and Planetary Sciences, has claimed that the future could be very bleak if we pass a threshold of carbon dioxide in our oceans.

Passing the threshold could cause a catastrophic feedback loop — the influx of carbon dioxide in the oceans causing extreme ocean acidification, which would lead to even more carbon dioxide being released.

This "global reflex," an MIT press release says, would cause huge changes in the amount of carbon contained in the Earth's oceans, with potentially dire ramifications.

Geological records

By using geological records, geologists like Rothman are comparing evidence from changes in layers of sediments preserved from hundreds of millions of years ago with the current levels of C02 in our oceans.

For his own research, Rothman looked through these records and observed that over the past 540 million years, the ocean's store of carbon changed abruptly — often changing dramatically before reverting to its previous level.

This “excitation” of the carbon cycle is most dramatically present near the time of four of the five great mass extinctions in Earth’s history.

In other words, patterns similar to the one we are currently witnessing have a correlation, in Earth's history, with catastrophic events.

Effects on our modern climate

Unlike previous spikes in carbon dioxide in the ocean, we are now seeing levels rise at a much faster level due to human pollution.

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As MIT's press release reports, "today’s oceans are absorbing carbon about an order of magnitude faster than the worst case in the geologic record — the end-Permian extinction."

In the past, it took tens of thousands of years or more for volcanic eruptions and other natural causes to trigger environmental problems. Humans, though, have only been releasing carbon dioxide into the atmosphere for hundreds of years — the rate at which it is happening is unprecedented.

Scientist Predicts "Mass Extinction" Caused by Breach of Carbon Threshold
Buoyant Gaussian Air Pollution Plume. Source: Public Domain/Wikimedia Commons

Today, we are “at the precipice of excitation,” Rothman says in the MIT piece.

If it does occur, evidence from previous global extinction events suggests that we may be facing a similar global catastrophe.

“Once we’re over the threshold, how we got there may not matter,” says Rothman. All we know is that humans are rapidly increasing the amount of CO2 in our atmosphere. “Once you get over it, you’re dealing with how the Earth works, and it goes on its own ride.”

Rothman is publishing his results this week in the Proceedings of the National Academy of Sciences.

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