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Comment by sprainedankles | Hacker News Reader

> The Arctic has been warming at least twice as fast as the rest of the world for the last 30 years, an observation referred to as Arctic amplification.

I didn't realize this (or at least, am surprised it's _twice_ as fast). Apparently the key factor is loss of sea ice. Can anyone ELI5?

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I'm not sure this is the reason for this specific observation, but one mechanism I've read of was that arctic air is very dry relative to equatorial, and any heating up increases its humidity, and in turn water vapor is a much more intense greenhouse gas than many other things, so it can cause more localized warming, which feeds a cycle. Why it isn't a complete runaway process i don't know, and I may be misremembering the details.

And of course, Siberia and Canada will start emitting vast amounts of methane as permafrost thaws.

At least if the northeast passage opens up, we'll have a sea route between china and europe that doesn't go past the resource-cursed middle east.

https://en.wikipedia.org/wiki/Northeast_Passage

Yeah but I think that diffuses everywhere after it happens, the humidity thing is a more localized effect.

Not sure if this explains it because it would require ice melting enough in areas to become just water with no remaining ice underneath, but albedo of ice and water is fairly different. Snow covered ice in particular. The change in the amount of solar radiation reflected vs. absorbed as ice / snow covered ice becomes water will drastically heat up an area.

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