According to a new study that was published in the journal Science, scientists believe that ocean acidification triggered by massive volcanic eruptions helped cause the worst mass extinction in the history of life on Earth, and that theory also can be applied to the human-generated carbon dioxide emissions that are contributing to climate change this present day.

The Los Angeles Time Science Now reported on April 9 that researchers studied chemicals in rocks in cliffs in the United Arab Emirates that, some 250 million or so years ago, had been submerged in an ancient ocean. They looked at the ratios of boron isotopes, which are closely linked to levels of ocean acidification, as well as certain carbon isotopes, which are often used to study the rate that carbon dioxide is entering the ocean (and thus, how acidic the ocean is becoming).

In a new research paper, a team led out of the University of Edinburgh has found that there were two major phases to this extinction that acted as a one-two-punch to wipe out most living things.

The scientists think that massive amounts of carbon dioxide were released by what’s known as Siberian Trap volcanism, which was then absorbed into the oceans, causing them to grow more acidic far too fast for ocean life to adapt. They also found that there appeared to be two phases to the carbon influx. The first one, signaled by the carbon isotopes, was a slower process that took place over 50,000 years; but the second phase was fast and furious, dumping massive amounts into the ocean in just 10,000 years.

“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,” lead author Matthew Clarkson of the University of Edinburgh said in a statement. “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.”