252 million years ago, volcanoes erupted a huge amount of lava onto the earth and carbon dioxide into the air, chemically altering the oceans in a way that would change life on earth forever. This incident — the Permian Extinction event — killed over 90% of the planet's species and 96% of marine species.
Countless theories have been put forward about why and how, exactly, this happened, but a new study, published in Science, offers some compelling evidence that acidification was a key factor.
So why should you care about ancient history? Well, our oceans are acidifying at a disturbingly similar rate right now — and it's our fault.
One of the lead authors, Matthew Clarkson, explained in a statement:
Scientists have long suspected that an ocean acidification event occurred during the greatest mass extinction of all time, but direct evidence has been lacking until now. This is a worrying finding, considering that we can already see an increase in ocean acidity today that is the result of human carbon emissions.
The University of Edinburgh researchers studied rucks in the United Arab Emirates that had been on the seafloor for hundreds of millions of years. There, they found chemical evidence of what, precisely, led to the Great Dying — that the oceans went from alkaline to acidic at a very fast pace (in geologic terms) over the course of a few thousand years.
In a second large pulse of volcanic eruptions, so much CO2 was ejected into the atmosphere that the oceans quickly acidified, creating a tragically inhospitable environment for marine life.
Oceans today are rapidly acidifying due to the same thing: increased CO2 emissions.
And much of marine life is already in grave danger from this acidification. It's contributing to the bleaching of coral reefs around the world, stunting lobster growth, killing sea snails in the Pacific, and threatening shellfish populations. If it gets any worse (and it seems to be headed in that direction), acidification could compromise the entire marine ecosystem, and, therefore, the land animals that depend on it, too.
So let me just drive the major point home here: The last time the oceans were this acidic, our planet was headed toward the greatest extinction in its history. If that's not a reason to work on reducing your carbon footprint — and encourage others to do the same — I have no idea what is.
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