SOURCE: Scientific American and San Diego Tribune (video)
DATE: September 15, 2017
SNIP: Deadly climate change could threaten most of the world’s human population by the end of this century without efforts well beyond those captured in the Paris Agreement.
That’s the finding of a pair of related reports released yesterday by an international group of climate science and policy luminaries who warned that the window is closing to avert dangerous warming. They say carbon dioxide might have to be removed from the atmosphere.
Scientists Yangyang Xu and Veerabhadran Ramanathan found in a paper published in the Proceedings of the National Academy of Sciences (PNAS) that there already exists a 1 in 20 chance that the 2.2 trillion tons of carbon dioxide in the Earth’s atmosphere could cause an existential warming threat. This “fat tail” scenario would mean the world experiences “existential/unknown” warming by 2100 — defined in the report as more than 5 degrees Celsius above preindustrial levels.
The report also found a 50 percent chance that temperatures would rise to 4 C under a business-as-usual scenario, a less extreme but still highly dangerous level. The long-term goal of the Paris accord was to maintain warming well below 2 C.