Imagine an event so cataclysmic that 96 per cent of all species on Earth become extinct.
That was the mass extinction at the end of the Permian period, 252 million years ago. As this year’s Earth Hour passed on Saturday, new evidence linking the Permian catastrophe to climate change triggered by burning coal is a warning to modern civilisation.
The end-Permian extinction was the worst ever to befall the planet, “when life nearly died”, as British palaeontologist Michael Benton’s book title expresses. It was much worse than the more familiar disaster that wiped out the dinosaurs and killed some 75 per cent of species 65 million years ago.
Atmospheric carbon dioxide rose sharply to five times today’s level, global temperatures climbed by 8°C, the ocean became more acidic and low in oxygen and the climate dried up. The iconic trilobites disappeared forever, for a time forests vanished from the face of the Earth and many corals, shellfish, insects, amphibians and reptiles died off. It took some 10 million years for ecosystems to recover, during which a few hardy species, such as the pig-like reptile Lystrosaurus, scratched a living among the corpses and detritus.
The death of the dinosaurs has been understood since 1980 to have been caused by the impact of an asteroid in modern-day Mexico. The Permian event has long been more mysterious, with no sign of an extraterrestrial origin. But from about 2000, scientists have been piecing together clues that point to something very wrong in the late Permian world – an environmental disaster.
Coinciding with the extinction is the massive volcanic outpouring that formed the Siberian Traps lava flows, in modern Russia. New research by geologist Ben Burger in Utah, finding high levels of lead and mercury in sediments from the time, fingerprints the burning of coal. Of course, there was no advanced species to burn coal deliberately at that time – but the volcanoes in Siberia appear to have ignited enormous coal beds, spreading ash clouds around the world, releasing carbon dioxide and causing global warming. This coal could have released some 11 trillion tonnes of carbon dioxide, equivalent of more than 300 years of the current world economy’s emissions.
Higher sea temperatures may then have destabilised methane hydrates, ice-like substances found in polar regions and under the sea-floor, which led to further warming. The sulphur pumped out by the volcanoes would have caused acid rain and, exacerbated by elevated levels of carbon dioxide, acidic water would dissolve the shells of sea-creatures. Oxygen-depleted oceans would release toxic hydrogen sulphide gas, which might then have weakened the planet’s ozone layer, exposing plants to destructive levels of ultraviolet rays.
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It is a compelling story that accords increasingly well with the geological evidence. And it is a worrying portent for our current situation. We are burning coal, oil and gas and adding carbon to the atmosphere much faster, if not on quite the same scale as at the end of the Permian.
We are already seeing signs of dangerous climate disturbance: the Arctic was unprecedentedly warm this winter. Greenland and the North Pole have been above freezing, a remarkable occurrence in the middle of 24-hour darkness. As Arctic ice melts, the darker sea-water absorbs more summer sunlight, accelerating the melting. Conversely, cold air of the polar jet stream has turned south, bringing freezing spells to North America and Europe. The threat of feedback mechanisms that cause further warming is growing more acute.
Deniers or minimisers of the threat of climate change may say that life has coped with higher global temperatures before, even if not of the extremes of the post-Permian world. Indeed, fish, plants and reptiles, would survive, but low-lying areas such as Bangladesh and Florida, not to speak of industrial civilisation, may not.
Or, they may say that such projections are extreme cases and that the likely warming is much less. That may be true, but it discounts the small but worrying possibility of disastrous upsets, that economist Martin Weitzman has shown to be the most compelling reason to mitigate climate change. Even small climatic shifts, such as a drought in a vulnerable region, can trigger conflicts and migrations with worldwide repercussions.
Of course, things probably won’t get as bad as an 8°C rise in temperature, because the global economy would collapse and greenhouse gas emissions drop long before. But that is not a very comforting prospect. Even if we can keep to the 2°C rise foreseen by 2016’s Paris Agreement, that is damaging and risky enough. Staying below 2°C requires global emissions to peak around 2020. But, although greenhouse gas emissions stayed flat during 2014-16, they rose 1.4 per cent last year as the world economy boomed.
The portrait of climatic disasters brings on a sense of hopelessness and fatalism in some, and a compulsion to denial in others. But we should instead see it as a warning and a call to action.
We have most, if not yet all, of the tools we need to build a strong global economy and society compatible with a liveable climate. While some politicians and pressure groups blunder in fruitless debates, other countries, companies and individuals get on with the hard work of creating and building low-carbon systems. We are not turning out the lights for Earth Hour, not hazarding the extinction of our civilisation, but instead building a cleaner, richer, fairer planet.
Robin M Mills is CEO of Qamar Energy, and author of The Myth of the Oil Crisis