We’ve Seen This Before: What The Extinctions in Our Geologic Past Indicate About the Dangers of Current CO2 Emissions

Deep CO2 in the end-Triassic Central Atlantic Magmatic Province

Manfredo Capriolo, Andrea Marzoli, László E. Aradi, Sara Callegaro, Jacopo Dal Corso, Robert K. Newton, Benjamin J. W. Mills, Paul D. Wignall, Omar Bartoli, Don R. Baker, Nasrrddine Youbi, Laurent Remusat, Richard Spiess, and Csaba Szabó

Summarized by Lisette Melendez. 

What data were used? 

This study investigates the large-scale volcanic activity that would eventually lead to the end-Triassic Extinction, one of the top five most devastating extinction events for life on Earth, that occurred about 201 million years ago. The volcanic eruptions took place across the globe, leading to a massive sheet of volcanic rocks known as the Central Atlantic Magmatic Province, or CAMP for short. Considering that the volcanic activity took place before the supercontinent Pangea was fully split apart, CAMP rocks can be found in North America, Africa, and Europe, as shown in Figure 1. Scientists used both intrusive (magma that crystallized underground) and extrusive (magma that cooled on the Earth’s surface) rock samples to investigate the amount of carbon dioxide, a greenhouse gas, released into the atmosphere during these catastrophic eruptions.

Methods: By analyzing the concentration of the carbon dioxide bubbles (Figure 2) trapped within the crystals that were formed during the volcanic eruptions, scientists can determine the speed and frequency of the eruptions. After collecting more than 200 samples, the concentration of carbon dioxide within the rocks was determined using microspectroscopy: a method that shows the spectra of the sample in order to identify and quantify the various compounds that are present. 

Results: Overall, there was a high volume of carbon dioxide bubbles within CAMP rocks. Since CO2 is an accelerant for magma eruptions, the volcanic activity was likely hasty and violent. The rapid rise of CO2 in the environment means CO2-removing mechanisms, like weathering, aren’t enough to balance out the excess CO2. This leads to a carbon dioxide buildup in the atmosphere, accelerating global warming and ocean acidification.

 

Figure 1: A map of the boundaries Central Atlantic Magmatic Province in central Pangea, around 200 million years ago. It shows how wide-spread the volcanic eruptions were during this time.

Why is this study important? The study of CO2 saturation in rocks helps us understand the role that volcanism played in the buildup of excessive greenhouse gases in the atmosphere that triggered the end-Triassic extinction. It showed that the more rapid the release of CO2 into the atmosphere is, the more severe the environmental impact.

The big picture: This study can be used as a warning for current trends, considering that the amount of CO2 emitted during the CAMP eruption roughly equals the amount of projected anthropogenic (i.e., human-caused) emissions over the 21st century. Just like in the past, the current substantial rise in CO2 is leading to a global temperature increase and a surge in ocean acidification, but we are releasing CO2 much faster than at any other time in Earth’s history. Considering that these are the same conditions that led to one of the worst biotic extinctions in Earth’s history, it is vital to encourage our governments to implement radical climate change policies in order to slow the current rise of CO2 to prevent more environmental destruction. 

Figure 2: The black arrows point towards the bubble-bearing inclusions within the rock samples using light optical microscopy. The high concentration of CO2 within these bubbles indicates the magma was rich in CO2. These four samples are specifically orthopyroxene (Opx), clinopyroxene (Cpx), and calcic palgioclase (PI), and were sampled from Canada and Morocco.

Citation: Capriolo, M. et al. Deep CO2 in the end-Triassic Central Atlantic Magmatic Province. Nat Commun 11, 1670 (2020).

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