'Earth was stressed before dinosaur extinction'
New evidence gleaned from Antarctic seashells confirms that Earth was already unstable before the asteroid impact that wiped out the dinosaurs.
The study, led by researchers at Northwestern University, is the first to measure the calcium isotope composition of fossilized clam and snail shells, which date back to the Cretaceous-Paleogene mass extinction event. The researchers found that -- in the run-up to the extinction event -- the shells' chemistry shifted in response to a surge of carbon in the oceans.
The researchers said that understanding how the Earth responded to past extreme warming and CO2 input can help us prepare for how the planet will respond to current, human-caused climate change.
"To some degree, we think that ancient ocean acidification events are good analogs for what's happening now with anthropogenic CO2 emissions," Jacobson said. "Perhaps we can use this work as a tool to better predict what might happen in the future. We can't ignore the rock record. The Earth system is sensitive to large and rapid additions of CO2. Current emissions will have environmental consequences."