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Comment by bambataa | Hacker News Reader

Recent research argued that the loss of the Greenland ice sheet is now inevitable: https://www.theguardian.com/environment/2022/aug/29/major-se...

Given the lag in the climate, isn’t 1.5C warming more or less unavoidable now? We would need extremely steep emissions reductions that aren’t happening.

I enjoyed ‘Under a Green Sky’, which combines a brief history of palaeontology (and amusing academic point settling) with the prediction that warming will eventually cause huge releases of hydrogen sulphide.

We are perhaps entering a negative feedback loop where disruption makes countries less keen to work together on emissions reductions as metaphorical bridges get pulled up (is Russia going to bother even pretending to care any more?).

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So historically in the climate modeling world, +6-8 degrees was considered the "we're all screwed" tipping point; this has led to recent optimism where it now looks like we'll probably level out at +2-3.5 degrees, and only some of us are screwed.

The major tipping points that are estimated at 1.5 degrees are Greenland, the West Antarctic Ice Sheet, and coral reefs dying off.

The former two have an associated sea level rise of about 3.5-4.5 meters all together.

So I think this article isn't changing the "some of us are screwed" narrative substantially; it's more interesting because it pulls out all of the major forecast disasters and gives estimates of when (temperature wise) they'll happen.

Also from this article, between 1.5 and 2 degrees:

> widespread abrupt permafrost thaw

Which is “fun” because that releases a boatload more carbon into the atmosphere.

And methane.

Yes, methane contains carbon.

Methane is, over the span of 20 years, a 84--86 times more potent Greenhouse gas, though.

As the sibling comment mentions methane contains carbon, but yes it’s worth pointing out because the short-term GHG potency of methane is extremely high. There’s potential for some terrible feedback loops here.

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

Everybody gangsta till the Clathrate gun pops off.

If you have a Clathrate gun in one chapter, it must go off in the next.

(not sure the scale of controversial this is) and anthrax and various other as-yet-unknown bacteria.

And perhaps small pox and other viruses from dead and frozen bodies in permafrost?

Are these side effects calculated in the models, or are the models too optimistic?

Historically climate change models have been too optimistic.

The other thing we have to consider is that if the model's range is between "everybody suffers" and "everybody dies" do you want to gamble with that?

Probably not. However, it seems that regardless of what they predict, nothing will happen.

Humanity is like a toddler, only learns when you feel the consequences, rather than learning by being told about it. Also like a stubborn toddler like first needing to experience an almost trauma to change behavior, and apparently we haven't had that trauma yet.

This article seems to indicate that the current models don’t account for some of it: https://climate.nasa.gov/news/2785/unexpected-future-boost-o...

> The impact on the climate may mean an influx of permafrost-derived methane into the atmosphere in the mid-21st century, which is not currently accounted for in climate projections.

(Note this is an unexpected type of abrupt thaw; the models probably do include the impact of more gradual permafrost thawing. Cold comfort though, and polar ice is melting at a faster rate than predicted overall.)

So are there any parts of the world that will benefit from global warming? Canadian and Russian wilderness?

Maybe, but it's not like great trade-off on a global scale.

Extreme latitudes are colder because they receive their sunlight at an angle. The tilt of the Earth and the seasons make things more complicated, but conceptually, if you are at latitude 45, you are also at a 45 degree angle relative to the sun, so sunlight is only 70% as intense as it is at the equator.

With increased global temperatures, northern latitudes may have longer growing seasons, but they'll still have a different, probably inferior climate to what you're losing further south.

So while there may be winners and losers on a global scale, the winners will probably win less than the losers lose.

Antarctica used to be a semi-tropical forest. Perhaps we'll all be living there!

I don’t know why, but the author’s writing style in Under a Green Sky irritated me so much I couldn’t get past the first few pages. Maybe it changes if I stick it out.

I think I know what you mean. He has quite an arrogant streak and is amusingly dismissive of large swathes of people (“the Basques are so dour!”). It’s worth persevering with, imo.

I do believe that we are doomed as mass extinction is now inevitable. I also believe that PTB will launch wars of depopulation to ‘thin the herd’, as it were…for survival of the species.

We can’t fight the planet. We quadrupled our population in just one century. Should have invested in anti ageing tech, reproductive technology and controlled our consumption/population. Point of no return now.

IIRC (sorry, no sources) there is no real "lag" or "inertia" in climate. It has been demonstrated that if we stopped any emission right now, the climate would rapidly stabilize to its current state (in a couple of years).

However, and maybe it's worse, human civilizations do have huge inertia when it comes to changing our way of doing things. I have no doubt that someday in the future, we will be a zero emission species. But I'm really unsure it will be soon enough.

I’m fairly certain that’s not the case, because even with current levels of warming all the polar ice that can melt at current temperatures has not yet. A short video on background:

https://youtu.be/Ix2XprA6A7I

That means some level sea level rise and any other climactic changes resulting from melting polar ice are coming regardless of what we do now. We can influence how much this happens, but we’ve already committed to a lot of damage.

Definitely not in a couple of years.

Our current situation is like a big glass of ice tea that you have set out in the sun. For some time it will remain cool and refreshing, but once the ice cubes have finished melting it quickly becomes warm and blah. We need to move it back into the shade, but that's not possible until we've invested heavily into carbon sequestration, and that's not even fully feasible yet. There are a few pilot programs here and there, but nothing that could be scaled up affordably. Not even close. Worse, any solution requires political will to implement, and as you can see from even this thread there are rich and powerful interests willing to spend a lot of lobbying money to make anything like it as politically unpopular as possible. Even in a normally calm and rational HN forum you have them stopping only slightly short of calling climate change activists the new Hitler. Carbon Capture is supposed to be the supply side of the carbon market, but since the technology doesn't exist those markets have never worked.

This goes against everything I’ve read on climate change and its long term effects. The world’s oceans are extremely slow reacting components of the climate. Wikipedia ”climate intertia”. If you have more recent data then please post.

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