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The phenomenon that is being described where melting ice causes the release of CO2 into the atmosphere seems to have been known to climate scientists, though I
by kdoherty 9y ago
The phenomenon that is being described where melting ice causes the release of CO2 into the atmosphere seems to have been known to climate scientists, though I don't know whether it has been included in climate change models.
There is a great talk (video online here: https://www.facebook.com/WoodsHoleOcean/videos/10154590312681372 https://www.facebook.com/WoodsHoleOcean/videos/1015459031268...) by Richard Alley where exactly this phenomenon is mentioned (see Q&A at ~50:55 in the video, though I highly recommend watching the whole thing).
- logfromblammo 9y agoThe trouser-soiling moment is when the methane clathrate ices start melting. They call that one the "Clathrate Gun" hypothesis, because you can't un-fire a gun. Once that trigger is pulled, no amount of anthropogenic CO2 emissions reductions will have any effect whatsoever. From then, it will take a positive, intentional, globally coordinated effort to reduce temperatures by other means, or we will be well and truly boned.
- crush-n-spread 9y agoWe need that global effort to happen yesterday. It's going to be much easier to get the carbon out of the atmosphere by leveraging the already-existing carbon cycle through accelerated silicate weathering than it will be to artificially reduce atmospheric temperatures once huge amounts of methane have been released from sea ice.
- 2OEH8eoCRo 9y agoDoesn't methane break down in the atmosphere fairly rapidly? From what I'm reading, methane lasts about 12 years while CO2 can stay in the atmosphere for potentially thousands. Unless we choke to death on methane isn't this less of an issue than CO2 buildup?
- stcredzero 9y agoMethane is a very potent greenhouse gas, and the release would be absolutely huge. The momentary spike would well cause a lot of CO2 to be released.
- mirimir 9y agoOn a positive note, while it may not suffice to save human civilization, CO2 likely won't get baked out of rocks. Or at least, it hasn't after previous "methane gun" events.
- stcredzero 9y agoWhat has been released after the previous "methane gun" events?
- mirimir 9y agoThe Paleocene–Eocene Thermal Maximum[0] and the Permian–Triassic extinction[1] may have involved "methane gun" events. 0) http://www.pnas.org/content/113/28/7739.full.pdf http://www.pnas.org/content/113/28/7739.full.pdf 1) http://www.bbc.co.uk/science/horizon/2002/dayearthdied.shtml http://www.bbc.co.uk/science/horizon/2002/dayearthdied.shtml
- istorical 9y ago"While CO2 persists in the atmosphere for centuries, or even millennia, methane warms the planet on steroids for a decade or two before decaying to CO2. In those short decades, methane warms the planet by 86 times as much as CO2, according to the Intergovernmental Panel on Climate Change." Source: https://www.scientificamerican.com/article/how-bad-of-a-greenhouse-gas-is-methane/ https://www.scientificamerican.com/article/how-bad-of-a-gree...
- mikeash 9y agoThe fear is that the change will be so fast and so drastic that the short lifetime won't save us. It's thought that runaway methane release could result in 6+ degrees (celsius) of warming within just a few decades as massive amounts of methane are released. The influence of methane would end relatively quickly too, but the damage would be incredible. Nobody is really sure if this would actually happen, though.
- fencepost 9y agoMethane does break down much faster than CO2, but over the time scales being discussed here it's MUCH more powerful. From memory so probably somewhat off it's >80x more potent a greenhouse gas over a decade, dropping to only 20x more potent when measured over a century. The big problem is tipping points. There are a lot of things where an initial big hit can be something you don't recover from, no matter how light the impact might seem when measured over years.
- ancientworldnow 9y agoThe latest IPCC report does not account for Arctic methane release. There were too many variables and they decided to omit it and avoid being alarmist. This is discussed on page 28 of WG1 AR5 SPM (the final 2013 IPCC policy maker report).