Nature - Strong Evidence That Large-Scale Methane Release Powered Rapid Warming 55 MYA (PETM) - AFP

[hatrack]

PARIS (AFP) - Methane released from wetlands turned the Earth into a hothouse 55 million years ago, according to research released Wednesday that could shed light on a worrying aspect of today's climate-change crisis.

Scientists have long sought to understand the triggers for an extraordinary warming episode called the Palaeocene-Eocene Thermal Maximum (PETM), which occurred about 10 million years after the twilight of the dinosaurs.

Earth's surface warmed by at least five degrees Celsius (nine degrees Fahrenheit) in just a few hundred or a few thousand years. The Arctic Ocean was at 23 degrees Celsius (73 degrees Fahrenheit) -- about the same as a tepid bath -- before the planet eventually cooled. Richard Pancost, a researcher at Britain's University of Bristol, seized an opportunity to dig, literally, into this mystery. Excavation of a site in southeast England to set down the Channel Tunnel rail link exposed layers of sediment from a bog that had existed at the time of the PETM. Pancost's team sifted through the dirt to measure the carbon isotope values of hopanoids, which are compounds made by bacteria.

They found that levels of these isotopes suddenly fell at the onset of the PETM, yielding a signature that can only be explained if the bugs dramatically switched to a diet of methane, a powerful, naturally-occurring greenhouse gas. Reporting in the British journal Nature, Pancost believes that the methane had remained locked up in the soil for millions of years before warming released it into the atmosphere.

EDIT

http://news.yahoo.com/s/afp/20070919/sc_afp/scienceclimatewarming_070919190046;_ylt=AiJeLPvl1G9gypzbYyUKCoprAlMA

[halobeam]

1. is my brain at this point scrambled eggs OR

Can this have an effect on the slowing the gulf stream? Be kind if I'm totally in "omelet stage", please.

[depakid]

2. The earth basically farted.

and with the permafrost turning into wetlands, it's probably about to do the same again.

[skids]

3. And possibly much faster.

It may not be a few hundred years this time. But I guess my sig says it all.

[glitch]

4. Such an awesome, beautiful little planet. It astounds me that some people think it's disposable.

K & R Another fascinating extinction is the Permian, they think unfreezing methane hydrate may've had a hand in accelerating a warming positive feedback loop.
http://www.bbc.co.uk/science/horizon/2002/dayearthdiedqa.shtml and http://www.realclimate.org/index.php?p=227

[Javaman]

5. Thank you for posting those links...

So many people worry about CO2, when CO2 although important is only a small part of the overall issue we have with climate change/global warming. If the methane that is trapped in the permafrost every gets released en masse the game is over.

climate change, to me anyway, isn't just about changing climates, it's about accelerating the end of everything as we know in in a very short amount of time.

The release and eventual flash over that would occur as a result of the methane release makes CO2 problems look like a walk in the park.

No one wants to bring this issue to the forefront.

[glitch]

6. I suppose it's too horrific to contemplate.

I feel that way about most global environmental issues, but runaway feedback loops hit a special panic button. I think I can look at other extinctions because that allows me to look at our current crisis from an imagined distance.

[GliderGuider]

7. The problem is that methane release amounts to a climatic singularity

Events like that are very hard to deal with quantitatively, whereas the slow steady release of CO2 as a result of burning fossil fuel lends itself to comprehensible modeling. I suppose that's the main reason tipping points haven't been incorporated into climate models until now - any predictions you might make about them have enormous error bars in both time and magnitude. Despite the potential magnitude of their effect, they are "known unknowns" and thus hard to deal with scientifically.

The idea that we could go from "not doing so bad" to "it's all over" in a geological instant is pretty dramatic, though, and more people every day are becoming aware of the possibility. Books like "with Speed and Violence" are helping to get the word out.

[Javaman]

8. Very good point.

Yeah, it's hard to measure the critical point of output of the methane, but I would think that a parts per million or billion would do the trick.

It's a sad state of affairs when the hard honest facts are put off till later when later is too late. :(

[GliderGuider]

9. Keep in mind the time factor for the methane release as well

Methane oxidizes to CO2 fairly rapidly following its release. That means it's much less persistent than CO2, even though it's over 20 times as powerful a GHG. That means that the rate of release is very important in determining the overall greenhouse effect that a given amount of methane will have. A huge release over the course of a decade would be much worse than a slow release of the same amount over a century. The greenhouse forcing over the decade would drive up the temperature quite rapidly. The temperature rise would then be augmented more slowly by the CO2 generated by the decay of the original methane. In the case of the slower release, you would end up with the same amount of CO2 oxidation product, but with less initial forcing and a lower final temperature because the concentration of methane wouldn't have been able to build up so high. So predicting the rate of release is critical to having an accurate model.

It's not that the hard facts are being put off, it's that a) we only just figured it out, and b) the mechanism is intrinsically hard to model. That means we can get out a qualitative message about the nature of the effect, but backing it up with numbers on a graph is going to be hard to do until we have some baseline data on what's actually happening out there, and how fast. Once we have some of that data, expect to see some truly frightening temperature models.

[Javaman]

10. Man, thank you for the truly terrifying education.

I don't know whether to thank you or run away from you. lol

I didn't know that methane oxidized to CO2 as quickly as you stated. I thought it took much longer.

I just get this really sick feeling in my stomach that once the calculations are finally in, we will have realized that the cork has been out of the bathtub for a very long time.

[GliderGuider]

11. No, the fact that it oxidizes rapidly is a good thing

The last thing you want is methane hanging around for a century, it's 23 times as potent as CO2. It's better that it decays quickly into the less noxious gas.

[phantom power]

12. Under the conditions of a massive methane release...

that makes me wonder how much free O2 it would bind up. Enough to drop the partial pressure of O2 by a percent or two? Partial O2 pressure has been significantly lower than today, at various times in the past.

[GliderGuider]

14. Fun with numbers

Let's see if I can do this...

CH4+2O2->C02+2H20

Atomic Weight of Hydrogen: 1
Atomic Weight of Carbon: 12
Atomic Weight of Oxygen: 16

So, 12+4(1) = 16 units of methane bind with 4(16) = 64 units of oxygen by mass.

So 1 tonne of methane will bind 4 tonnes of oxygen.

The speculated content of the Siberian peat bogs is about 70 gigatonnes of methane. That's enough to reduce 280 Gt of oxygen. The world's atmosphere contains about 1,000,000 Gt of oxygen, so about 0.03% of it would be reduced if all that methane was released in a big fart.

Clathrates are another concern. The estimate is that they store about 2,000 Gt of carbon, so that means they contain 1.3 times that mass of methane: (from the atomic weights, 12+4(1))/12). Thhat would reduce 2000*1.3*4 = 10,400 Gt of oxygen. That's still only 1% of the total free oxygen, though I bet close to the oceans the local loss of partial pressure might make you a bit short of breath.

However, that 2000 Gt of carbon in the clathrates is 2.5 times the total amount currently in the atmosphere. It would raise the CO2 concentration to 1000 ppmv, and turn the Earth into a giant Easy-Bake Oven. So the big deal really is still the greenhouse effect, not immediate anoxia.

[Javaman]

17. and you call that fun? yikes!

Thanks for the info, I can use this for a little project I'm working on. :)

Cheers.

[phantom power]

18. 1000 ppmv. Wow, that would be something new and different.

Not good, but surely new and different.

[Javaman]

13. yes and no...

it's good that it does oxidize, but it's bad that it can't be potentially controlled the way man made CO2 can be.

If we can get a cap on our CO2 pollution then realistically, it would (hopefully) decrease the methane release to oxidation/CO2, but given the fact that we are unable to control our own output, this, I would believe, only accelerate the positive feed back loop that will be created when to much CO2 is in the atmosphere.

then when to much CO2 is in the atmosphere this will inturn accelerate the permafrost melting and lead to the scary potential of a large melt and methane release that can't oxidize quickly resulting in a flash over.

Is this correct reasoning?

[GliderGuider]

15. Yeah, you've got it right.

Frightening, ain't it?

[Javaman]

16. enough for night sweats. nt