New evidence of a long-term planetary thermostat to remove excess CO2

[sue4e3]

Scientists working in the North Atlantic have found the clearest geologic evidence yet of a planetary thermostat that counteracts the warming cause by massive amounts of greenhouse gas by absorbing CO2 into the rocky sediments of the Earth itself.

The researchers said they analyzed ocean floor sediment off the coast of Newfoundland to confirm a sudden release and subsequent removal of CO2 that occurred 56 million years ago during the Paleocene-Eocene Thermal Maximum (PETM). That event, in which thousands of petagrams of carbon were released into the atmosphere and ocean in just a few thousand years, is considered by many researchers to be the closest ancient analogue to today's rise in atmospheric carbon levels.
"It's long been thought that when the planet warms, as it did during the PETM, the rate of rock weathering on land, which absorbs CO2 from the atmosphere, increases. This draws down CO2 and cools the planet back down again," said Yale University geologist Donald E. Penman, a postdoctoral fellow in the lab of Pincelli Hull and first author of a paper reporting the findings in the journal Nature Geoscience.


Read more at: http://phys.org/news/2016-07-evidence-long-term-planetary-thermostat-excess.html#jCp

[MrModerate]

1. Hmm. Fascinating. Nature never loses its ability to surprise and delight. n/t

[NickB79]

2. And it only took many tens of thousands of years to remove

"We believe this process is going to operate in response to carbon emissions related to human activity," Penman said. "But if the PETM is any guide, it will take tens of thousands of years."

Good luck to humanity and most of the planet's other lifeforms trying to survive in the meantime.

[OnlinePoker]

3. This puts things into an interesting perspective

In the 57 years of record keeping at Mauna Loa, atmospheric CO2 has increased from 316.57 ppm to 400.83 ppm (to the end of 2015) for a net increase of 84.26 ppm. I found a page from 2011 that calculated how many petagrams of CO2 the atmosphere increases for every one PPM and they calculated 2.134 petagrams. Based on this, since the Mauna Loa record started, atmospheric CO2 has increased by 179.81 petagrams. Preindustrial CO2 levels were around 270 ppm so, given that, total CO2 in the atmosphere has increased by 279.2 pg.

http://how-it-looks.blogspot.ca/2011/07/petagrams-of-carbon.html

[NickB79]

4. It is damn scary how similar the PETM is to what we're doing today

For example: http://archive.unews.utah.edu/news_releases/past-global-warming-similar-to-todays/

Bowen and colleagues report that carbonate or limestone nodules in Wyoming sediment cores show the global warming episode 55.5 million to 55.3 million years ago involved the average annual release of a minimum of 0.9 petagrams (1.98 trillion pounds) of carbon to the atmosphere, and probably much more over shorter periods.

That is “within an order of magnitude of, and may have approached, the 9.5 petagrams [20.9 trillion pounds] per year associated with modern anthropogenic carbon emissions,” the researchers wrote. Since 1900, human burning of fossil fuels emitted an average of 3 petagrams per year – even closer to the rate 55.5 million years ago.

And we haven't even seen much of the predicted positive feedbacks from a thawing Arctic really kick in yet.