New research puts current human forced climate change in the same context as some of the worst extinction events in the geological record including the End Permian Extinction.
The Permian Mass Extinction 251.9 million years ago, otherwise known as “The Great Dying,” was the closest this planet has come to extinguishing all complex life on Earth. Around 90% of all species died out in this single event, a worse toll even than the Cretaceous extinction that wiped out the dinosaurs.
For years the cause of the Permian Mass Extinction has been linked to massive volcanic eruptions in Siberia. Volcanic CO2 and a cocktail of noxious gasses combined with burning coal and geothermally-baked methane emissions to enact a combination of toxic effects and, most importantly, ocean acidification and global warming. It led to a world where equatorial regions and the tropics were too hot for complex life to survive. That’s a fact so astonishing it bears repeating: global warming led to a large portion of planet Earth being lethally hot on land and in the oceans! The cascading extinctions in ecosystems across the planet unfolded over 61,000 years, and it took 10 million years for the planet to recover! For comparison, our distant ancestors separated from apes only 7 million years ago.
Until recently the scale of the Permian Mass Extinction was seen as just too massive, its duration far too long, and dating too imprecise for a sensible comparison to be made with today’s climate change. No longer.
Burgess et al’s paper brings the Permian into line with many other global-warming extinction events, like the Triassic, the Toarcian, the Cretaceous Ocean Anoxic Events, The PETM, and the Columbia River Basalts, whose time frames have been progressively reduced as more sophisticated dating has been applied to them. They all produced the same symptoms as today’s climate change – rapid global warming, ocean acidification, and sea level rises, together with oxygen-less ocean dead zones and extinctions. They were all (possibly excluding the PETM - see below) triggered by rare volcanic outpourings called “Large Igneous Provinces,” (LIPs) that emitted massive volumes of CO2 and methane at rates comparable to today’s emissions. The PETM may also have been triggered by a LIP, although that is still debated.
Can we seriously expect Earth’s climate to behave differently today than it did at all those times in the past?