(CN) — A rapid rise in CO2 emissions primarily released by the Siberian Traps volcanism drove the end-Permian mass extinction 252 million years ago which obliterated 90% of all marine species and 70% of land species including insects — a "rare distinction among the major extinction events."
A study published Monday in the journal Proceedings of the National Academy of Sciences analyzed previously unstudied compound-specific carbon isotopes derived from drill cores collected at the Finnmark Platform in Norway. Samples like this are particularly useful because “they are relatively well preserved compared to the outcrop because they haven't gone through all the weathering, surface weathering, that the outcrops have commonly experienced,” study author Ying Cui said in an email. These samples also contain information about pollen and spores, which sheds further light on what was happening on land during the extinction event.
According to study author Mingsong Li, the study has “three advantages: 1) our new astronomical time scale enables a 10,000-year temporal resolution for the paired marine and terrestrial carbon isotope records; 2) the carbon isotope data are not affected by dissolution or truncation; 3) the inversion using carbon isotope records with a high-resolution astronomical time scale considering existing pH records offers insights into the size of the true carbon isotope excursion and the rate and duration of the carbon emissions.”
The scientists then incorporated all this data into sophisticated Earth system models, which produced a detailed reconstruction of the time scale of the event. Li said one notable takeaway from this study is "the inversion of the Earth system model suggests the atmospheric pCO2 increases by 13x pre-extinction level at a maximum rate of 4.5 Pg C/yr, this is only half of the present-day 10 Pg C/yr carbon release rate.”
But Cui noted the present rate of carbon emissions is “pretty much on the same order of magnitude” as it was during the end-Permian mass extinction event — though there are key distinctions, she said..
“The paleogeography of the Permian is different; the ocean chemistry of the Permian is also very different from today. There's not an exact or perfect analog for what's going on right now,” Cui wrote.
Another surprising insight from the study is that the studied material has a particularly high sedimentation rate in contrast to previous studies of the end-Permian extinction.
“Other global sections with records for the end-Permian extinction with reliable time constraints usually have a very low sedimentation accumulation rate (say, <1 cm per thousand years), here, the time series analysis demonstrates this studied material have a very high sedimentation rate at 22 cm per thousand years. This enables reliable estimation of the timeline of the end-Permian mass extinction,” Li wrote in an email.
According to Cui, knowing or understanding the pH change of oceans and the spikes in global temperature — increases of between 45 and 72 degrees Fahrenheit — is integral to quantifying how much carbon was generated during the event. The study compared the observed data with the model results for the global surface temperature, sea surface temperature from the east and southeast and the global surface pH value.
“So, it's really, really important to have not just the temperature, but also the pH change. Because you know, pH…as another layer of constraints…will help us quantify how much carbon is needed to generate the amount of pH change and how fast the carbon was added,” Cui wrote.
The scientists believe the rise in carbon emissions during the end-Permian extinction was too significant and occurred too quickly for most species to adapt.
“So, I think that the duration was less than 10-20,000 years for the most rapid carbon emissions. The organisms probably don't have the time to react to all of these changes, all at once,” Cui wrote. She also noted a number factors occurring simultaneously contributed to the extinction, but “we think that this very rapid and massive CO2 emission played a critical role in driving all of that."
The Siberian Traps volcanism occurring around the same time as the major extinction phase points to its involvement in this rapid rise of CO2.
The cost of the mass extinction event lies not only in the unimaginable death toll it yielded but also in how long it took for Earth’s biodiversity to recover.
“Studies on the early Triassic recovery suggest that the ecosystem did not fully recover until several million years after the extinction,” Cui wrote.
Subscribe to Closing Arguments
Sign up for new weekly newsletter Closing Arguments to get the latest about ongoing trials, major litigation and hot cases and rulings in courthouses around the U.S. and the world.
Additional Reads
-
-
Shell, climate activists wrap appeal of landmark Dutch case April 12, 2024
