[RandomLensman]

In what scenario is climate change removing humans from the planet? If we cannot handle/manage/remove a mere 2-3 degree increase (which is about the current trajectory), sooner or later natural variation will doom us.

The great filter might very well be the unwillingness to consider more than mono-thematic solutions mixed with doomsterism, though.

[esarbe]

You might be underestimating the social upheaval that will result from wast regions of the earth becoming uninhabitable and the effect of the population movements from desperate people trying to get away starvation.

You might also be underestimating the consequences of ecosystem collapse. Since 1970 we've already lost about 60% of biomass of insects, birds and mammals. The impact of rapid climate change will put additional pressure on already vulnerable species.

I have little doubt that widespread ecosystem collapse will be the death nail for our global human civilization.

[RandomLensman]

So you are an expert in these things that you don't trust other experts? Catastrophic collapse is not really something generally assumed on the 2-3 degree warming path.

[gameoverhumans]

> So you are an expert in these things that you don't trust other experts

I don't see how the grandparent comment implied a lack of trust in other experts, nor did they imply themselves to be experts.

> Catastrophic collapse is not really something generally assumed on the 2-3 degree warming path.

Actually, the IPCC, which tends to be rather optimistic on how bad things could be (or already are), predicts pretty significant socioeconomic problems arising from 2-3 degrees warming: https://en.wikipedia.org/wiki/Shared_Socioeconomic_Pathways

It doesn't take much imagination to come up with ways that "Social cohesion degrades and conflict and unrest become increasingly common" leads to "nation states with nukes and experiencing extreme scarcity and high social unrest declare war on each other"...

[RandomLensman]

Your imagination might not be a good guide to take you from degrading social cohesion to something like nuclear war.

Even in general, socio-economic models are not of the same quality as the physics models (and no-one is making that claim anyway). The SSPs are more like share narratives rather than forecasts.

[gameoverhumans]

Okay so we've established that neither my imagination, nor the labors of the Intergovernmental Panel on Climate Change are any good for determining how likely we are on course for nuclear war.

You know that humans do have nukes, right? And a long history of killing each other over pretty much anything? (from land rights to idealogies and everything in between).

So in your estimation, who would be a good source to determine how/whether humans get to a point where nuclear war is a likely scenario?

[RandomLensman]

I explained to you what the SSPs are.

Why the obsession with nuclear war and trying to get totally imprecise scenarios there? They serve very little purpose other than building scary narratives. Some people's job is to worry about them, but that doesn't mean they are central to what we should do.

When a hurricane strikes, things are usually not just Lord Of The Flies - the idea of collapse into violent chaos is a popular one but doesn't really happen much.

[esarbe]

I'm not sure what you are talking about re "experts" - I'm very much basing my statements on the conclusion drawn by experts.

I don't think that there's any expert out there that will deny that 3°C warming will lead to massive population movements.[0] Experts also conclude that there's already significant damage to ecosystems that will only increase with that kind of global warming[1].

But that's a little besides the point.

In the Paris climate agreement of 2015 we agreed to limit global warming to 1.5°C. Barely 8 years later we've blown through that limit and there is no credible effort to reduce or even stop the warming.

Models parametrized so that they predict a 2-3°C increase until the end of the century have already been invalidated since all of them expected 1.5°C to be breached by 2030 earliest - we're seven years ahead of schedule.

Right now we're on a track that even our modern neutered climate models predict will lead to a +5°C before the end of the century.

[0] https://www.ipcc.ch/report/sixth-assessment-report-working-g...

[1] https://www.nature.com/articles/s41586-020-2189-9

[RandomLensman]

1.5C is gone - no point clinging to it. However, there is a lot if effort going into decarbonization. Where we are exactly is unclear, but claiming we are on track to 5C isn't really supported by that many (having past models being invalidated doesn't mean certain future overshoot, how much of invested changes are captured, etc.).

Also, the ecosystem discussion is somewhat orthogonal as we don't now what all is critical to human survival.

[esarbe]

> 1.5C is gone - no point clinging to it.

And soon 2.0C will be gone - no point clinging to it, right?

> However, there is a lot if effort going into decarbonization.

I don't see a lot of effort going into decarbonization. We still have about 7% of global GDP going into subsidies for fossil fuels. That's a lot of effort against decarbonization [0].

There is little actual progress being made[1]. Whatever reduction we had can be directly attributed to the economic upheaval created by the Covid pandemic.

> having past models being invalidated doesn't mean certain future overshoot

Given that our actions in the last 20 years pretty much track the "business as usual" scenario and given that we can eliminate all models that predict a warming of 1.5°C to arise any later than 2024, we're pretty much only left with models that give us a warming of 5°C until 2100[2]. Please note that even that is in the lower bound; the IPC 8.5 has a lower bound of 1.4°C in the 2040 - we've blown past that already. It's only getting worse.

> Also, the ecosystem discussion is somewhat orthogonal as we don't now what all is critical to human survival.

I'm not sure if you are joking or what. Our dependency on an intact ecosystem is absolute - we cannot exist without it. The "services" that the biosystems around us provide is invaluable and we utterly depend on them. Trying to quantify how much of it you can destroy for the sake of industry and profit is akin to asking how much of your liver you can sell away for cocaine.

[0] https://www.imf.org/en/Topics/climate-change/energy-subsidie...

[1] https://ourworldindata.org/co2-emissions

[2] https://en.wikipedia.org/wiki/Representative_Concentration_P...

[MattPalmer1086]

This is a problem in how warming is reported in my opinion. Saying it's just 2 or 3 degrees doesn't sound like a lot. But that is warming the whole planet on average by that amount. This is a lot of energy being injected into the climate, and regional variations and extreme weather will be much more severe.

[gameoverhumans]

Meh I dunno, there's that website that reports how many hiroshimas of energy we're releasing into our planet per second, the skeptics/denialists don't seem to care much for that metric, either.

I don't think the problem is how it's being reported, I think it's just that this is the kind of news some people will do anything but hear.

[MattPalmer1086]

I hadn't heard of the Hiroshima's per second before. That sounds like the kind of metric that might change a few minds.

Denialists won't listen to anything anyway, but I think there's probably a lot of people who hear 1 or 2 degrees (globally) and just think meh, doesn't sound so bad.

[gameoverhumans]

I went looking for the website I was thinking of, but instead I found this article from The Conversation: https://theconversation.com/four-hiroshima-bombs-a-second-ho...

Dated 2013. 10 years ago we were already talking about how we're releasing 4 Hiroshimas into the atmosphere per second. Good thing that woke everyone up and enacted a decisive response to the existential thr---- oh.

[MattPalmer1086]

Well, I think that's the point of that article. It says that we need to communicate in terms people can relate to better (than just some average temperature over the whole planet).

So no, we weren't talking like that 10 years ago, but we had identified that we needed better messaging. But we did nothing about that.

[esarbe]

Just try to imagine the ludicrous amount of energy required to heat up the whole surface - and probably a good part of the ocean - by 2°C.

I think it is in the order of 10^17 joules or so.

[mr_mitm]

But that is distributed over a ludicrous amount of volume. These numbers are so large that I can visualize neither. How is this information supposed to help me?

[esarbe]

First I would check the number that I gave you and make sure it is correct. Then you put it into perspective; e.g. how many millennia would it take for a couple of hundred nuclear reactors to produce that much of energy.

Play with the numbers and see what you can learn about them.

Not sure you need to consider that much of a volume; we're talking about surface temperature, so you can just take an approximation of heat capacity of the surface of Earth.

[adrianN]

For it to be a Great Filter, it needs not to wipe out humanity completely, it's sufficient to end technological civilization. A nuclear war over resources can easily do that. As Covid has shown, even minuscule disruptions can lead to widespread scarcity, so a nuclear war might not even be necessary.

[RandomLensman]

I could also say: covid showed that despite widespread disruption, technology civilization actually didn't collapse at all.

Anyone can imagine any kind of doom scenario, but then I could justify inaction all the time: if it isn't warming, an asteroid will get us or aliens or nuclear war or ..., so why bother?

[theshrike79]

Covid didn't cause a mass migration a 2-3 degree increase in temperatures will make big parts of Africa, India and China unliveable for a good part of the year due to wet bulb temperatures. Anyone without working AC will just die.

Those three contain about 2 BILLION people. That amount of people deciding that it's time to live somewhere else will cause issues. Our current migrant problems are a drop in the bucket compared to that.

[gameoverhumans]

> covid showed that despite widespread disruption, technology civilization actually didn't collapse at all.

What I hear: "hey look, I pulled a piece out of the Jenga tower and it didn't collapse! Clearly from this I can infer that more pieces can be pulled without any consequences!"

> if it isn't warming, an asteroid will get us or aliens or nuclear war or ..., so why bother?

Uh, because we don't have control over foreign sentient beings, nor the path of celestial bodies? Do you really not see the difference between those things and anthropogenic warming as a result of rapid industrialization?

[RandomLensman]

You think we are physically unable to build an asteroid defense?

Anyway, I didn't say we should do nothing about climate change (and we are doing a lot), but if the counter to everything is: not enough, doomed anyway - then, yes, totally happy not to work in that field anymore.

[gameoverhumans]

> You think we are physically unable to build an asteroid defense?

Mate the dino-nuking asteroid that hit Earth was 10km in diameter. Even if we launched every nuke we had at such an object, it wouldn't do much to deter such an object. And that's assuming it's moving at a low enough fraction of c that we could actually detect such an object in time to mobilize all said nukes.

So, no, I don't think we would be able to defend ourselves today (nor by 2100, let's say) against such an adversary. Same deal with any species that is sophisticated enough to do interstellar travel. For them it's even easier, they can just pick up a few rocks from Kuiper belt, stick some mass drivers on them and it's bye-bye Earth within a few weeks/months.

> (and we are doing a lot)

The point is we're not. We haven't even reached peak fossil fuel yet. Even if we stopped everything tomorrow, things would still keep getting worse for at least another few decades. But as it is we're reading today about how bad we made things for ourselves in the 80s. Since then our consumption has only continued to accelerate, which can only mean things will be even worse tomorrow.

> but if the counter to everything is: not enough, doomed anyway

No. That's not what I or anyone else in this thread has been saying.

It's like this. We are on the Titanic. Some very clever people have charted our course and done ocean sonographs and determined there's a big-ass iceberg ahead. Many folks like you are insisting either a) there's no iceberg or b) icebergs are good for ship hulls or c) we'll out-technology the iceberg somehow and thus we don't need to worry about the iceberg. So right now all we've done is ACCELERATE towards the iceberg. If there was sensible suggestions like "let's alter our course slightly" I wouldn't be saying "well that still puts us on course for the iceberg so there's no point". I would be saying "great! that's a start!".

[RandomLensman]

Well, I can see how you don't see that we are doing a lot. Thankfully that is not distracting people from doing.

[Delomo]

With 3-6 degrees we will see sea level rise of a few meters. This already affects a lot of coastal regions.

And there is still a big question mark if we don't break something fundamental on the road ahead.

It might not eradicate us but millions and millions / billions will suffer.

[RandomLensman]

We are not on a 3-6C trajectory, why discuss the implications there?

[Delomo]

We are.on a 2-3 by 2100 projection. That's not far away

[bonzini]

Do we even know what's the trajectory?

[RandomLensman]

Yeah, we have a reasonable good idea because we can not only see the past but also investments and plans etc.

[brookst]

Sooner or later I’ll die of cancer so I might as well go BASE jumping without a parachute.

[nerdponx]

> sooner or later natural variation will doom us.

Correct, but we have managed to convert "later" to "significantly sooner".

The fact that eventually the climate would have changed unfavorably anyway at some unknown point in the future is no reason to be comfortable with humans inducing an unfavorable change right now. That's like saying there's no point in getting an oil change because the car engine is going to wear out eventually anyway. or like saying you might as well smoke and drink as much as you want because everyone dies at some point.

[RandomLensman]

I am saying we already on a path not in the catastrophic collapse space and we need and will be able to handle things, because we need to for far more problematic things in the future anyway.

[solumunus]

“Sooner or later” could be hundreds of thousands or even millions of years though, so I don’t think your point holds much weight.

[ClumsyPilot]

Human race handled the Blacl Death, but was it fun? It can probably survive a global nuclear war, but is it a great idea?