Researchers in the Netherlands have linked massive carbon injections in the atmosphere to the end-Triassic mass extinction (ETME, ~201.4 million years ago), which was marked by terrestrial ecosystem turnover and up to a ~50% loss in marine biodiversity.
In a paper published in the journal Science, they present compound-specific carbon-isotope data of long-chain n-alkanes derived from waxes of land plants, showing a ~8.5 per mil negative excursion, coincident with the extinction interval.
These data indicate strong carbon-13 depletion of the end-Triassic atmosphere, within only 10,000 to 20,000 years. The magnitude and rate of this carbon-cycle disruption can be explained by the injection of at least ~12 × 103 gigatons of isotopically depleted carbon as methane into the atmosphere. Concurrent vegetation changes reflect strong warming and an enhanced hydrological cycle. Hence, end-Triassic events are robustly linked to methane-derived massive carbon release and associated climate change.
...The ETME interval, with rapid and large-scale carbon release, may be regarded as a natural deeptime analog to today’s anthropogenic carbon emissions. Cumulative anthropogenic carbon release of >5000 Gt likely will enhance greenhouse warming by several degrees and substantially lower oceanic pH values. Earth’s biosphere also is projected to experience major disruption of ecosystems, with associated loss of biodiversity. A direct link between massive carbon release and the ETME suggests that modern-day ecosystems could experience a further loss in biodiversity, not only by habitat reduction but also by carbon release–driven rapid climate changes.—Ruhl et al.
Micha Ruhl, Nina R. Bonis, Gert-Jan Reichart, Jaap S. Sinninghe Damsté, and Wolfram M. Kürschner (2011) Atmospheric Carbon Injection Linked to End-Triassic Mass Extinction. Science 333 (6041), 430-434 doi: 10.1126/science.1204255