February 21st, 2015
Although history has often revealed itself to be cyclical, this is one cirsumstance humanity should hope to never repeat. A new paper presented last week at the Geological Society of America uncovered why plants and animals did not quickly recover from the largest mass extinction in Earth’s history.
The era passed 250 million years ago, but the culprit was a familiar offender: global warming.
The environmental impact of rising temperatures stagnated species recovery for 5 million years.
The Early Triassic period was marked by a surge in global volcanic activity. The era, now called the “Great Dying” offers cautionary clues as to how climate change might impact life today, said Ohio State University PhD candidate Alexa Sedlacek, lead author of the paper.
Matthew Saltzman, professor of earth sciences at Ohio State and Sedlacek’s academic advisor offered his perspective: ”The lesson is, life doesn’t just snap back. We’ve long known from the fossil record that there was a long period with very little recovery right after the Great Dying. It’s as if life had a 5-million-year hangover. Now we know why.”
Sedimentary rock that formed on a tropical ocean floor 250 million years ago, were among the samples Sedlacek and Saltzman analyzed. After the volcanic eruptions of the Great Dying, chemicals they found in the rock confirm that massive amounts of the Earth’s surface were being weathered away by greenhouse gases in the atmosphere. The planet’s climate was chemically altered for millions of years after and the ocean remained highly acidic.
“People are understandably interested in the Great Dying because 90 percent of marine species went extinct,” Sedlacek said. “But the recovery from that event is equally important, because the survivors determined what kind of life we have on Earth today.”
Chemical elements in samples of limestone were gathered from northern Iran, which was a tropical ocean during the Early Triassic period, 252 to 248 million years ago.
”If you want to know what’s going to happen in the future, looking at the past provides an important perspective,” said Saltzman. “Global warming has happened before, and in some cases the consequences were severe.”
Sedlacek, A. Saltzman, M. Algeo, TJ. Horace, M. Richoz, S. Brandner, R. & Foland, K. (2012). Coupled C and SR Isotope Stratigraphy of the Early Triassic of Zal, Iran: A Record of Increased Weathering GSA 2012 Annual Meeting & Exposition
Image: Andrea Della Adriano, Creative Commons