*In “The Great Dying” 250 million years ago, the end came slowly*
The deadliest mass extinction of all took a long time to kill 90 percent of Earth’s marine life–and it killed in stages–according to a newly published report.
It shows that mass extinctions need not be sudden events.
Thomas Algeo, a geologist at the University of Cincinnati, and 13 colleagues have produced a high-resolution look at the geology of a Permian-Triassic boundary section on Ellesmere Island in the Canadian Arctic. (more…)
By studying fossilized mollusks from some 3.5 million years ago, UCLA geoscientists and colleagues have been able to construct an ancient climate record that holds clues about the long-term effects of Earth’s current levels of atmospheric carbon dioxide, a key contributor to global climate change.
Two novel geochemical techniques used to determine the temperature at which the mollusk shells were formed suggest that summertime Arctic temperatures during the early Pliocene epoch (3.5 million to 4 million years ago) may have been a staggering 18 to 28 degrees Fahrenheit warmer than today. And these ancient fossils, harvested from deep within the Arctic Circle, may have once lived in an environment in which the polar ice cap melted completely during the summer months. (more…)
SAN FRANCISCO — The northernmost mummified forest ever found in Canada is revealing how plants struggled to endure a long-ago global cooling.
Researchers believe the trees — buried by a landslide and exquisitely preserved 2 to 8 million years ago — will help them predict how today’s Arctic will respond to global warming.
They also suspect that many more mummified forests could emerge across North America as Arctic ice continues to melt. As the wood is exposed and begins to rot, it could release significant amounts of methane and carbon dioxide into the atmosphere — and actually boost global warming. (more…)
A new study of the High Arctic climate roughly 50 million years ago led by the University of Colorado at Boulder helps to explain how ancient alligators and giant tortoises were able to thrive on Ellesmere Island well above the Arctic Circle, even as they endured six months of darkness each year.
A new study shows the Arctic climate system may be more sensitive to greenhouse warming than previously thought, and that current levels of Earth’s atmospheric carbon dioxide may be high enough to bring about significant, irreversible shifts in Arctic ecosystems.
