2016-03-23. Current Carbon Emissions Unprecedented in 66 Million Years.

posted Mar 29, 2016, 3:13 AM by Alan Gould
By JoAnna Wendel, EoS Earth and Space Science News (AGU). For GSS Climate Change chapter 6. Excerpt: As scientists attempt to understand how anthropogenic climate change will affect the Earth’s future, they often study a period in the Earth’s deep past, called the Paleocene-Eocene Thermal Maximum, when a period of natural climate change significantly heated the Earth. In a Nature Geoscience paper published Monday, scientists established that this warming, which began 56 million years ago, was the result of a 4000-year period in which carbon was released into the atmosphere at a rate of 1.1 petagrams (or 1.1 trillion kilograms) per year. The Paleocene-Eocene Thermal Maximum (PETM) “is the biggest, most massive carbon release event since dinosaurs disappeared,” said Richard Zeebe, a biogeochemist and paleoceanographer at the University of Hawai‘i at Mānoa in Honolulu and lead author on the paper. ...Because the rate of carbon dioxide release is 10 times faster today, the severity of climate change’s physical effects on the Earth, such as ocean acidification, could be much worse than we thought, Zeebe said. ...Researchers see evidence of marine life extinction during this time due to ocean acidification, Zeebe said, especially in the deep-sea communities of tiny, shelled organisms. ...a paper in Nature Geoscience in 2011 that determined that today’s rates of carbon dioxide emissions are 10 times higher than those during the onset of the PETM. Because the ocean absorbs much of the carbon dioxide, the consequences for marine life, especially shelled creatures, could be worse than during the PETM, Zeebe said....  https://eos.org/articles/current-carbon-emissions-unprecedented-in-66-million-years