Scientist Warns Of Mass Marine Extinction

9 October 2017

 - Nations that agreed in Paris in 2015 to take steps to limit global warming in fact do so, then by 2100 humans will have added 300 billion tons of carbon to the seas. And a U.S. scientist has calculated that the critical threshold for mass extinction stands at 310 billion tons.

So in either case, the world will be condemned to, or at imminent risk of, a “great dying” of the kind that characterized the end of the geological period called the Permian, in which 95 percent of marine species vanished, or the Cretaceous era that witnessed the last of the dinosaurs.

Daniel Rothman, a geophysicist at the Massachusetts Institute of Technology, reported in the journal Science Advances that he worked through hundreds of scientific studies to identify 31 occasions of significant change in 542 million years in the planet’s carbon cycle—in which plants draw down carbon from the atmosphere and cycle it through the animal community and back into the atmosphere.