Permian Extinction Carbon Release > Mass Of All Fossil Fuels - But Our Rate Of Release Faster

Mods: press release.

EDIT

Scientists have proposed many possible reasons for the extinction, including asteroids, volcanoes and low levels of oxygen in seawater. Payne and his colleagues earlier thought that carbon isotope evidence pointed to volcanoes, but they couldn't definitively distinguish between that and the other possibilities.

Two years ago, they realized that the calcium in limestone could hold the answer, because the types of calcium present in the ancient rocks would be different for each extinction scenario.

By looking at changes in the ratio of heavy to light calcium isotopes in fossils from different time periods and determining their "calcium signature," the team could infer the chemical changes – and their origin – that occurred in the environment.

The scientists ground up the limestone deposits, which spanned the pre- and post-extinction periods, and analyzed them to determine the relative presence of calcium isotopes. They found that the changes in the ratio matched the calcium signature predicted for ocean acidification, and the matching carbon dioxide signature pointed to carbon release from volcanic eruptions.

"Our best geologically supported idea is that the carbon dioxide release is related to the Siberian Traps volcanoes," Payne said.

Payne calculated that the eruptions, which lasted upward of a million years, released 13,000 to 43,000 gigatons (1 gigaton equals 1 billion tons) of carbon in the atmosphere. By comparison, scientists estimate we would release an estimated 5,000 gigatons of carbon if we used up all the fossil fuels in the Earth.

During the eruptions, huge amounts of carbon dioxide and molten rock burst through the Earth's crust, burning through coal and limestone, and releasing carbon dioxide into the atmosphere. That made oceans and rainwater more acidic, and dissolved more calcium from rocks into the ocean.

Payne said humans may not ultimately release as much carbon dioxide as the Siberian Traps, but we may be doing it at a faster rate. The end-Permian extinction could be viewed as a "worst-case scenario" for what we could be facing as we burn more fossil fuels and increase ocean acidity, he said.

"We won't necessarily end up with a world that looks as bad as it did after the end-Permian extinction, but that event highlights the fact that things can go very, very wrong," Payne said.

The National Research Council recently reported that the ocean's chemistry is changing faster than it has in hundreds of thousands of years, because carbon dioxide is being released into the atmosphere and absorbed into the oceans, making them more acidic. Studies have shown increased ocean acidity decreases photosynthesis, nutrient absorption, growth and reproduction of marine organisms.

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http://news.stanford.edu/news/2010/april/prehistoric-mass-extinction-042710.html

""We won't necessarily end up with a world that looks as bad as it did after the end-Permian extinction, but that event highlights the fact that things can go very, very wrong," Payne said.

So it could be worse, I guess.

:sarcasm:

Previously posted:

http://www.democraticunderground.com/discuss/duboard.php?az=show_mesg&forum=115&topic_id=129285&mesg_id=129362

:eyes: