Department of Earth and Environmental Sciences News
New Insights in Environmental Changes Leading to End-Permian Mass Extinction
Applying today’s computerized climate models to events millions of years ago could tell scientists about climate change in the Earth’s future, according to University of Texas at Arlington Assistant Professor Arne Winguth.
Winguth’s research focuses on a period of climate change and mass extinctions at the boundary of the Permian and Triassic periods, about 251.5 million years ago. At that time, more than 70 percent of species on land and 95 percent of species in the oceans became extinct. Many of the ocean species affected were invertebrates such as the trilobites. On land, early amphibians and reptile species died out.
Scientists have concluded that a rapid increase in carbon dioxide emissions and global warming – possibly caused by increased volcanic activity - could have triggered the extinction.
“It’s a very fascinating topic not only in respect to biology and evolutionary, but also to the geochemical and climatic variations,” Winguth said. “That’s also interesting looking to the future because we know that greenhouse gas concentrations in the atmosphere increases every year. The Permian-Triassic boundary is kind of an extreme scenario of what we can expect for the future.”
Winguth will present an abstract of his research this month at the Geological Society of America’s 2011 Annual Meeting & Exposition in Minneapolis. The presentation, called “Influence of cloud feedbacks on the end-Permian marine mass extinction,” explores how ocean stagnation caused by global warming led to decreased emissions of dimethyl sulfide and dimethyl disulfide into the atmosphere.
Organisms like microalgae and phytoplankton, which were less plentiful because of stagnation, release dimethyl sulfide and dimethyl disulfide as biproducts. Computer models run by Winguth and his coauthors show that less of those two sulfides being released into the atmosphere can cause an optical thinning of clouds, or decreased reflectivity, and significantly accelerate global warming by increasing the absorption of the sun’s rays at the ground.
Winguth’s research is funded through a grant from the National Science Foundation. Such work allows climatologists to test computerized climate models against known geological history. That confirmation will help scientists better predict how increases in temperature will affect life in the future, he said.
“We’re using the past climate to validate our theories,” he said.
Winguth’s presentation at the conference is part of a daylong session on the Permian-Triassic events.
Coauthors on the abstract are Jeffrey Kiehl and Christine Shields, both of the National Center for Atmospheric Research in Boulder, Colo. The research is a collaborative project with the University of Cincinnati, Pennsylvania State University, University of California, Riverside and Louisiana State University. Harry Rowe, UT Arlington assistant professor of earth and environmental science, is also a collaborator.
A paper on Winguth’s research into the Permian-Triassic boundary mass extinction was recently accepted for publication by the journal Geology, the publication of the The Geological Society of America. Winguth’s wife, adjunct research professor Cornelia Winguth, is the lead author on the paper called “Simulating Permian–Triassic oceanic anoxia distribution: Implications for species extinction and recovery.”
Several graduate students from the UT Arlington College of Science will also present work at the Geological Society of America’s annual meeting Oct. 9-12. Their topics include mapping of the Missouri River and methods for trace elemental analysis of mineral deposits called speleothems. About 6,000 scientists are expected to attend the conference.
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