Science Now:Earth's greenhouse gas levels approach 400-ppm milestone

Greenhouse gases on target to reach highest levels since dinosaur era

coalplantThe ratio of carbon dioxide in Earth's atmosphere is flirting with 400 parts per million, a level last seen about 2.5 million to 5 million years ago, according to the Scripps Institution of Oceanography at UC San Diego.Scientists estimate that average temperatures during the Pliocene rose as much as 18 degrees Fahrenheit. Sea levels during that 2.8-million-year epoch ranged between 16-131 feet higher than current levels, according to Richard Norris, a Scripps geologist.

"I think it is likely that all these ecosystem changes could recur, even though the time scales for the Pliocene warmth are different than the present," Norris said. Heating the ocean probably will cause sea level rises and change the Ph balance of the ocean, affecting a wide array of marine life, he said. "Our dumping of heat and CO2 into the ocean is like making investments in a pollution bank," he said.

to Read More: http://www.latimes.com/news/science/sciencenow/la-sci-sn-greenhouse-gas-...