2011-06-06 10:23:07Today's Carbon Release to Atmosphere 10 Times Faster Than PETM (yup, we're screwed)
Daniel Bailey
Daniel Bailey

Carbon Release to Atmosphere 10 Times Faster Than in the Past, Geologists Find

ScienceDaily (June 5, 2011) — The rate of release of carbon into the atmosphere today is nearly 10 times as fast as during the Paleocene-Eocene Thermal Maximum (PETM), 55.9 million years ago, the best analog we have for current global warming, according to an international team of geologists. Rate matters and this current rapid change may not allow sufficient time for the biological environment to adjust.

"We looked at the PETM because it is thought to be the best ancient analog for future climate change caused by fossil fuel burning," said Lee R. Kump, professor of geosciences, Penn State.

However, the researchers note in the current issue of Nature Geoscience, that the source of the carbon, the rate of emission and the total amount of carbon involved in this event during the PETM are poorly characterized.

Investigations of the PETM are usually done using core samples from areas that were deep sea bottom 55.9 million years ago. These cores contain layers of calcium carbonate from marine animals that can show whether the carbon in the carbonate came from organic or inorganic sources. Unfortunately, when large amounts of greenhouse gases --carbon dioxide or methane -- are in the atmosphere, the oceans become more acidic, and acid dissolves calcium carbonate.

"We were concerned with the fidelity of the deep sea records," said Kump. "How do we determine the rate of change of atmospheric carbon if the record is incomplete? The incomplete record makes the warming appear more abrupt."

Kump and his colleagues decided to look at information coming from areas that were shallow arctic ocean bottom during the PETM. During a Worldwide Universities Network expedition to train graduate students from Penn State, the University of Southampton, University of Leeds, University of Utrecht and University of Oslo in how projects develop, the researchers visited Spitsbergen, Norway. They uncovered a supply of rock cores curated by a forward-thinking young coal-mining company geologist, Malte Jochmann.

"Deep-sea cores usually have from 10 cm to a meter (about 4 inches to 3 feet) of core corresponding to the PETM," said Kump. "The Spitsbergen cores have 150 meters (492 feet) of sediment for the PETM."

The larger sediment section, made up of mud that came into the shallow ocean contains organic matter that can also supply the carbon isotope signature and provide the greenhouse gas profile of the atmosphere. With the larger core segment, it is easier to look at what happened through time and ocean acidification would not degrade the contents.

"We think the Spitsbergen core is relatively complete and shows an interval of about 20,000 years for the injection of carbon dioxide during the PETM," said Kump.

Using the data collected from the cores, the researchers forced a computer model to in essence run backward. They set up the models to find the proper amounts of greenhouse gases and atmospheric temperature that would have resulted in the carbon isotope ratios observed in the cores.

The outcome was a warming of from 9 to 16 degrees Fahrenheit and an acidification event in the oceans.

"Rather than the 20,000 years of the PETM which is long enough for ecological systems to adapt, carbon is now being released into the atmosphere at a rate 10 times faster," said Kump. "It is possible that this is faster than ecosystems can adapt."

Other Penn State researchers on this project include Ying Cui, graduate student and Katherine H. Freeman, professor; geosciences, Christopher K. Junium and Aaron F. Diefendorf, former graduates students and Nathan M. Urban former postdoctoral fellow.

Other researchers include Ian C. Harding, senior lecturer, and Adam J. Charles graduate student, National Oceanography Centre Southampton, University of Southampton, UK and Andy J. Ridgwell, professor of Earth system modeling, School of Geographical Sciences, University of Bristol, UK.

The National Science Foundation, Worldwide Universities Network and Penn State supported this work.

Story Source:

The above story is reprinted (with editorial adaptations by ScienceDaily staff) from materials provided by Penn State, via EurekAlert!, a service of AAAS.

Journal Reference:

  1. Ying Cui, Lee R. Kump, Andy J. Ridgwell, Adam J. Charles, Christopher K. Junium, Aaron F. Diefendorf, Katherine H. Freeman, Nathan M. Urban, Ian C. Harding. Slow release of fossil carbon during the Palaeocene–Eocene Thermal Maximum. Nature Geoscience, 2011; DOI: 10.1038/ngeo1179



From the Abstract:

The transient global warming event known as the Palaeocene–Eocene Thermal Maximum occurred about 55.9Myr ago. The warming was accompanied by a rapid shift in the isotopic signature of sedimentary carbonates, suggesting that the event was triggered by a massive release of carbon to the ocean–atmosphere system. However, the source, rate of emission and total amount of carbon involved remain poorly constrained. Here we use an expanded marine sedimentary section from Spitsbergen to reconstruct the carbon isotope excursion as recorded in marine organic matter. We find that the total magnitude of the carbon isotope excursion in the ocean–atmosphere system was about 4‰. We then force an Earth system model of intermediate complexity to conform to our isotope record, allowing us to generate a continuous estimate of the rate of carbon emissions to the atmosphere. Our simulations show that the peak rate of carbon addition was probably in the range of 0.3–1.7PgCyr−1, much slower than the present rate of carbon emissions.


(Aye, Cap'n: I no cannae find a wee free copy...)

2011-06-06 12:16:51
Rob Painting

Yooper, this being your area, are you planning a post? I've read quite a bit of Ridgewell and Kump's work on ocean acidfication in deep time (no, I'm not volunteering, just sayin').   

2011-06-06 12:17:43
Rob Painting

Oh, just noticed your comment at the bottom.

2011-06-06 13:16:35All yours, Dude ;)
Daniel Bailey
Daniel Bailey

Besides, I owe Agnostic some time, got the Curtis post to work on, Mauri has an idea for a post he wants to explore and the Trenberth thing should start moving soon.

Not to mention it's my son's Prom night tonight, got a job interview process to go through starting tomorrow (about 2 weeks tube time), the wife wants me to paint the kitchen and my daughter's school gets out this week for summer.

Life is beautiful.

2011-06-06 14:48:47
Dana Nuccitelli

This definitely warrants a blog post.  What do you say, Rob?

2011-06-06 16:02:42
Rob Painting

It would be nice to tie this in with studies trying to establish where exactly the carbon came from, the acidification & extinction of the bottom-dwelling marine life, and the comparatively unharmed surface dwellers, suggests that it came from oceanic methane hydrate reservoirs, IIRC.

Dana, if someone can get me a copy of the paper, I'll see if I can do it justice. 

2011-06-06 17:04:07


@Daniel, thank you for pointing that out, very interesting!

The conclusion is:

"The quantities of carbon added during the PETM span the
estimates of current fossil-fuel resources, suggesting that the PETM
could serve as a good analogue for future warming. However, the
peak rates of PETM carbon addition in these simulations (also see
refs 9, 15 and 25), and in complementary simulations based on other
published isotope records, are a small fraction of the present rate
of fossil-fuel burning. Thus, although the current overall capacity
for society to perturb the carbon cycle is comparable to that of the
PETM, the rate at which we are imposing the current perturbation
on the Earth system may be unprecedented."

@Rob: It should be in your email account!