Massive permafrost thaw documented in Canada, portending huge carbon release

We've been largely winning against the sea since 1500, and that's with windmills and wheelbarrels of mud. Look up the Afsluitdijk. Or the Deltawerken. Our combined 'water defense works' are considered one of the modern wonders of the world. The Dutch will never surrender to the sea. Even if the rest of the globe will experience some catastrophic flood, the Dutch will figure out how to stave it off.

"Now" still seems like a very good answer. I doubt that if we stopped emissions today, we'd see any positive changes for decades, and that's if we're very very lucky.

which term do "we" have control of exactly? also... define "we"?

Speaking for myself, I live in a country in which my current elected leader claims that CO2-related climate change is a hoax perpetrated by the Chinese and who plans (essentially politically unopposed, at least for the next 2-4 years) to undo what little protection prior administrations have put into place to try to help.

This does not give me a feeling of having any control whatsoever over the situation, but I'd love to hear what you think the realistic options are.

As no one has mentioned it in the comments, the belief that this is concerning is related to the "Clathrate gun hypothesis"[1].

Essentially, low temperatures have allowed vast quantities of methane and carbon dioxide containing compounds to accumulate for millennia. If the temperatures rise above a critical threshold, a positive feedback loop would exist between temperatures and global warming.

Positive feedback loops are scary.

[1] - https://en.wikipedia.org/wiki/Clathrate_gun_hypothesis

I'm not sure I understand your question correctly. It is not a question of time but of system parameters.

I just dug through the literature to get this right. The only study I found that actually modelled the feedback of the rising temperature due to emitted greenhouse gases (CO2 and CH4 - methane) on the permafrost says that any model they ran with a climate sensitivity above 3°C (how the system reacts to a doubling of CO2 or equivalent in the atmosphere [1]) produced a runaway effect, that is, atmospheric CO2 content keeps rising even if anthropogenic emissions stop in 2013 (which, as you know, they didn't). The current state on climate sensitivity is 3°C +-1.5°C.

They estimated some parameters conservatively too. So it could be worse. Or better - there are still a lot of uncertainties.

- The way carbon is released into the atmosphere can happen in different ways, and that can lead to different ratios of carbon in the air and other reservoirs like water or soil in bound form, as well as different ratios of methane and CO2 (they have vastly different atmospheric lifetimes and warming potential, so this matters).

- The total amount of carbon stored in permafrost soils is unclear. Permafrost can be very thick and deep, and large areas are hard to access. edit: Estimations are that the reservoir holds about twice that of the current atmosphere. Some of that will definitely go into the ocean and biosphere, but it's still a lot.

- Permafrost has a range of interesting behaviour during the freeze-thaw cycle (if you're interested, check it out, the features it produces are really neat). It is unclear how they change with temperature differences, and it influences the melting and release of carbon.

- Other climate-related effects such as flooding, increased vegetation etc have an influence. How much? Hard to say.

- Once the permafrost starts melting, carbon is released with a time delay, which is also not clear.

.. and so on. Non-linear effects, effects highly dependent on topography, micro-climate, vegetation... very hard to model in a consistent way. So.. it might be wrong too. Let's hope so.

The new balanced state will need years to centuries to be reached too, since thawing takes time. There is permafrost beneath the northern oceans. How? It's still there from the last ice age.

A note on time: The numbers I found for increased temperature due to permafrost melting by 2100 are in the 0.1°C-0.7°C range [2]. So we're probably fine. The ones after us.. well. There are some other feedback mechanisms that still require research. It would be great if something there helped us.. or we are all horribly wrong. That would be brilliant.

[1] https://en.wikipedia.org/wiki/Climate_sensitivity

[2] http://iopscience.iop.org/article/10.1088/1748-9326/9/8/0850...

http://www.nature.com/ngeo/journal/v5/n10/full/ngeo1573.html

This one is behind a paywall. :(