Jerri-Lynn here. A new MIT study shows that carbon levels could be approaching a threshold that previously triggered ocean acidification that was followed by mass extinction events.
“Once we’re over the threshold, how we got there may not matter,” says David Rothman, professor of geophysics and co-director of the Lorenz Center in MIT’s Department of Earth, Atmospheric and Planetary Sciences. “Once you get over it, you’re dealing with how the Earth works, and it goes on its own ride.”
I would have liked to include a link to the full study. Alas, it has not yet been published – but will be later this week, in the Proceedings of the National Academy of Sciences. Rothman’s research was in part funded by NASA and the National Science Foundation.
This Common Dreams account is a bit short. Until the full study appears, interested readers may find further detail in this slightly longer account released Monday by the MIT News Office: Breaching a “carbon threshold” could lead to mass extinction.
Common Dreams notes that the Rothman study represents a clear call for immediate action to reduce the amount of carbon currently being pumped into the world’s oceans. As necessary as that might be – and crucial to the survival of many forms of life on earth – in a week in which Trump managed to deliver a major environmental speech without mentioning climate change, such action looks unlikely. Or if it does come to pass, the US government won’t be playing any sort of leading role.
The continuous accumulation of carbon dioxide in the planet’s oceans—which shows no sign of stopping due to humanity’s relentless consumption of fossil fuels—is likely to trigger a chemical reaction in Earth’s carbon cycle similar to those which happened just before mass extinction events, according to a new study.
MIT geophysics professor Daniel Rothman released new data on Monday showing that carbon levels today could be fast approaching a tipping point threshold that could trigger extreme ocean acidification similar to the kind thatcontributed to the Permian–Triassic mass extinction that occurred about 250 million years ago.
Rothman’s new research comes two years after he predicted that a mass extinction event could take place at the end of this century. Since 2017, he has been working to understand how life on Earth might be wiped out due to increased carbon in the oceans.
Rothman created a model in which he simulated adding carbon dioxide to oceans, finding that when the gas was added to an already-stable marine environment, only temporary acidification occurred.
When he continuously pumped carbon into the oceans, however, as humans have been doing at greater and greater levels since the late 18th century, the ocean model eventually reached a threshold which triggered what MIT called “a cascade of chemical feedbacks,” or “excitation,” causing extreme acidification and worsening the warming effects of the originally-added carbon.
Over the past 540 million years, these chemical feedbacks have occurred at various times, Rothman noted.
But the most significant occurances took place around the time of four out of the five mass extinction events—and today’s oceans are absorbing carbon far more quickly than they did before the Permian–Triassic extinction, in which 90 percent of life on Earth died out.
The planet may now be “at the precipice of excitation,” Rothman told MIT News.
On social media, one critic called the study’s implications about life on Earth “completely terrifying.”
if the carbon cycle is nearing a natural positive feedback point – well – completely terrifying https://t.co/gXVnoITpo0
— steve crandall (@tingilinde) 9 July 2019
“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 that event, at least 90 percent of all life on earth died. https://t.co/16CCtyQeWG
— David Wallace-Wells (@dwallacewells) 9 July 2019
The study, which was completed with support from NASA and the National Science Foundation, also notes that even though humans have only been pumping carbon into the oceans for hundreds of years rather than the thousands of years it took for volcanic eruptions and other events to bring about other extinctions, the result will likely be the same.
“Once we’re over the threshold, how we got there may not matter,” Rothman told MIT News. “Once you get over it, you’re dealing with how the Earth works, and it goes on its own ride.”
Other scientists said the study, which will be published this week in the Proceedings of the National Academy of Sciences, represents a clear call for immediate action to drastically reduce the amount of carbon that is being pumped into the world’s oceans. Climate action groups and grassroots movements have long called on governments to impose a moratorium on fossil fuel drilling, which pumps about a billion metric tons of carbon into the atmosphere every year.
“We already know that our CO2-emitting actions will have consequences for many millennia,” says Timothy Lenton, a professor of climate change and earth systems science at the University of Exeter. “This study suggests those consequences could be much more dramatic than previously expected.”
“If we push the Earth system too far,” Lenton added, “then it takes over and determines its own response—past that point there will be little we can do about it.”