I think even our ability to start fire at will is conclusively known to be only ~50,000 years ago.
https://en.m.wikipedia.org/wiki/Control_of_fire_by_early_hum...
You don't need to be able to start a fire, when you keep the fire burning all the time. And you can do that, once you control the fire and figure out the difference between dry and wet wood.
Also humans are the dominating species on land since quite a while. Hunting certain species to extinctiom has certain effects on the local ecosystem and globally on the global climate. It all adds up.
But things surely changed in dimension since industrialisation.
I'm not sure what your perspective on this situation is but I think the case for modern anthropogenic climate change with deleterious effects is based on a wide range of different evidence, and a careful accumulation of facts and analysis. Simply pointing out that humans had fire 2Mya doesn't change the general conclusion about today.
https://en.wikipedia.org/wiki/Oklo_Mine
Fun to imagine the possibilities.
They is not the same as proof in my book. I also did poorly in school. I'm not good at taking this as stated. I enjoy wallowing in the unknown rather than believe everything I'm told to me own detriment.
And I agree: the history of the Earth is interesting. Which is why so many people study and work in the field of geology.
I'm completely an armchair ponderer.
The American south (Arizona, Florida) were tiny and unimportant until air conditioning entered the chat. Phoenix was at 100 thousand people in the fifties.
The cold makes us think, the cold make us survive, keeps us on the edge - where we need to be. Respek the cold!
Sumeria and Egypt both had seasonal flooding. Italy and Greece have winters that are cold enough to disrupt agriculture. The Aztecs and Mayans had seasonal floods. The ancient Chinese empires had both. Japan has winters. The list goes on.
The Inuits of Greenland and Sami people of Lapland didn’t have Aristotle or Confucius.
I find it hard to believe they wouldn't philosophise at all. Confucius got famous (like sun tzu et al) because his ideas were written down, published and spread.
It does make one wonder if any ancient sea fearing humans happened to carve a world map into a durable material such as granite which could have survived until the modern historic era. Maybe such a map, or other mythological artifact fueld the Roman idea of Terra Australis Incognita
/End rampant unsupported armchair speculation
With no evidence I believe navigation cues were built into the vessel. By keeping celestial bodies aligned with marks on the vessel one can achieve a seasonal calendar as well as documentation on how to modify the configuration for the next leg of the journey.
Source: Have a Pacific art collection, have been to most of the major museums on the subject, interested in sailing, authored some of the Wikipedia (featured) articles on related watercraft.
What I think is interesting is the physical representation of an oral tradition. This is different than writing as employed today.
What I seem to be noticing is that the ancients used calculus all the time but it was the geometric tools that they used.
This gave technology a form.
Arabic numerals made tabular data more useful leading to the more number based tools.
This seems to have removed the form from technology.
- What caused the temperature above Greenland to be 5°C warmer than today? Why is it cooler now compared to 120,000 years ago? What causes the interglacial periods? Is glaciation the more common state of the climate?
- The article says the ice sheet is melting at the bottom? Why? Pressure from above? Friction from movement? Heat from the Earth? Something else?
- Was the ice sheet shrinking or growing when the temperatures above Greenland were 5°C warmer than now? Does existence of the ice sheet imply that 5°C warmer for some period of time is not enough to melt the Greenland ice sheet?
- How much climate data has been lost to melting from the bottom? Is the ice sheet thickening or thinning compared 120,000 years ago? How would we know?
- How much has the Greenland land mass moved in 120,000 years due to plate tectonics? Could this have impacted the ice sheet in this short amount of time?
- Humans adapt. How did humans adapt to a climate that was warmer by up to 5°C 120,000 years ago?
- How long did the warm temperatures persist 120,000 years ago? 10,000 years? 50,000 years? Or more?
- Could a cooling climate be more worrisome to humanity than a warming one?
It’s not a theoretical science thing. We have farms and cities and towns and bridges and dams and reservoirs in particular places, and we are accelerating the depreciation of many of them. The result will be tremendous loss of wealth, movement of populations, and the associated social consequences of those.
Humanity doesn’t hate itself, we like ourselves, which is why we are so concerned about what we are doing to ourselves.
Yeah. The argument that single cellular life or some small animals might survive and eventually evolve into something else is a bit weird for people who are hoping they don't die out like many species have in the past when there have been major changes to climate and carbon levels.
Preventing climate change is about saving humanity, not the planet.
Because it forces us to recognize that the risk isn't to "the Earth" as a separate entity, but to ourselves specifically (well, our future descendants).
We've already confirmed through our behavior that humans largely don't care about any other part of the Earth ecosystem, so asking people to basically do the right thing as a favor to the Earth are probably wasting their time.
But Climate change is different, it speaks to the psyche of humans, the modern story of the flood. And in the same way it gives people meaning & without religion in the West they form morality around it. Those for it, are good, those against it, are bad.
That doesn't mean its not something important or real, and we have to solve it. But it's one of the many things for us humans to solve.
*In worst prognoses, climate changes will affect 10 mil deaths per year, which is the same amount cancer is doing every year today.
The worst case projection for 2100 for just sea rise is 4-5m on global average (but much higher in some areas) https://iopscience.iop.org/article/10.1088/1748-9326/acb504
To put that into perspective the average altitude of Bangladesh is 9m above sea level, but the majority of the population lives in he south at about 0-1m of altitude. So there would just in Bangladesh alone be more people (let's say 50% of 160M) directly affected by climate change than alzheimer world wide. We are not even talking about the indirect effects of displacing 60M people, all the other countries and all the other effects of climate change.
Apart from that, the argument is under the false premise that we shouldnt do anything anyway because there is worse things. By that argument we should also not do something about alzheimer, because more people die of cancer.
So I question what your aim was with your argument. It was clearly using wrong facts and was under a false premise.
If tides are rising over a 100 years, that's not something that happens all of a sudden, people have time to change their environment.
Affected by climate change is not the same as affected by alzheimer, cancer, etc...
[1] this is just one I found from a quick search, there is a lot more out there: https://www.theguardian.com/news/2022/aug/18/century-climate...
UN org claims 3.4 million per year by the end of the century: https://www.v-20.org/new-health-data-shows-unabated-climate-...
The considered things like spread of mosquitos.
See one here: https://www.forbes.com/sites/dishashetty/2021/07/30/climate-...
Oh shut it. You can't have any knowledge at all about this issue and not appreciate that the problem is not temperature as such but the rapidity of the change - over 150 years rather than 15000. Your troll post is an insult to intelligence.
Folks, don't waste your time trying to reason with such bad-faith arguments. It's a form of theft, because the time cost to refute bullshit is about 10x that to spew bullshit. And the above post is just that - bullshit.
Before someone invokes the HN guidelines and talks about curious conversation, recognize that throwing phrases like 'doomsday cult' into a discussion of a serious scientific project that has hit a milestone after many years of effort has only one purpose, and that is to derail. Flagging and downvoting are all very well, but there are also times when it's necessary to call bullshit.
There is also dissent among scientists, including from Nobel Laureates. "The doomsday cult" reference comes from the doom & gloom sensationalism. For example, I a heard chorus of "we are fucked" from coworkers in the office about 15 years ago in response to some news back then. I don't agree that "we are fucked". Humans have been through more environmentally challenging times with less technology & global knowledge.
The climate is changing...always has changed & always will change. What are we going to do about it? Are we going to pretend that we can stave off the inevitable, taxing/restricting the population which weakens their ability to adjust to these inevitable changes...while wealth is concentrated to the elites? There is a widespread perception that is happening. When the issues reach it's crescendo in later in this decade, there will be many who will not buy the APGW narrative as the reason for their problems. The peaceful solution is a decoupling from these systems, which I expect to happen. There will probably be more geopolitical problems though.
I think the animus generated by the present attitude over climate alarmism reduces effective cooperation among people & will be exasperated as the climate does change, as the Geomagnetic wander deepens in it's cycle, as magnetic fields fluctuate in our solar system, etc. A spirit of cooperation will help humanity while the blame game will hurt humanity.
I don't think any mainstream models predicted that? Which model was that?
Also remember that our actions are influenced by models. "If current trends persist, then in 20 years [...]" may very well be true, but if we take action based on those predictions (e.g. change the trend) then the outcome will be different.
You can see this clearly in population levels of things like elephants[1] or whales[2]: people who were predicting the extinction of whales and elephants weren't wrong.
[1]: https://ourworldindata.org/grapher/african-elephants
[2]: https://www.researchgate.net/figure/General-estimated-popula...
The most outlandish sensationalist claims grab mainstream attention (no snow by 2020) and when the predictions turn out not to be true, the advocates retreat to "well it was never a mainstream model". Classic Motte & Bailey. So in this case, the models that predict doom & gloom in the mid-term future saturate the media (Bailey) and when the predictions turn out to be false, it was claimed to never be a mainstream model (Motte).
If it's not a mainstream model, why are news outlets scaring the population with these fringe models? Even the IPCC director is chiding the doomsayers to not be so extreme in their prognostications.
Weather reports now use scary red color schemes to represent highs when a few years ago, higher highs were represented with a sun & blue color scheme. News coverage of heat outweigh coverage of summer time record lows & record sized hail in the mid US & Europe.
> Also, the ozone holes, acid rain, and things like Y2K. “This thing would have been very bad, but we (expensively, with great effort) fixed it, so it was okay” somehow becomes, in the public imagination, “this was not a real thing”.
The decrease in large volcanic eruptions had a large impact on the restoration of the ozone layer, which coincided with the ban on CFCs in 1987.
https://en.wikipedia.org/wiki/List_of_volcanic_eruptions_150...
Don't get me wrong, I'm in favor of reducing air pollution. However, there are other factors. A new ozone hole was recently discovered & the "Cosmic Ray Electron Reaction" model shows that non-human factors have a significant impact. So we have three factors, such as volcanic eruptions, CFCs, & Cosmic Rays which can deplete the ozone layer.
https://bgr.com/science/scientists-found-a-massive-new-hole-...
I think this drives at the heart of this discussion. Even if we ban CFCs, holes in the ozone layer will still occur. Even if we ban CO2, climate change will still occur. Due to change being inevitable, the best investment is in adaptation. An effective system of adaptation covers all of the possible cases. Banning CO2/CFCs does not stop climate change/ozone layer depletion, leaving us in the same position of needing to adapt.
Adaption is pro-people while bans are pro-institutions. I favor helping the people in tangible ways instead of funneling money to large capital interests & the elite cadre. Funneling money to the elites always enables corruption & waste. I would rather everyone be strengthened to adapt to the coming changes to the climate instead of forcing them to have faith in institutions led by the elites that will be unable to stop the climate changes, but have promoted fringe models to scare the people into complying with funneling money to the elites.
https://en.wikipedia.org/wiki/Extinction_event https://en.wikipedia.org/wiki/Holocene_extinction
So although the human species will probably survive a drastic climate change, many individuals will not due to famine, lack of medical supplies and care, and war over the remaining resources.
The major ecological shifts may bring change humanity does not bounce back from.
I'm not saying humans won't be fine but we've never been so dependent on the stability of the climate before. People will die, get displaced, suffer economically, etc as far as I understand.
[0] https://www.climate.gov/news-features/understanding-climate/...
https://en.wikipedia.org/wiki/Carbon_dioxide_in_Earth%27s_at...
Of course, there were also mass migrations and extinctions as the environment changed so radically, which seems like something that would be nice to avoid.
> On the positive, the earth has been much warmer and much colder, and has had more carbon and less carbon in the atmosphere.
the way I read it suggesting that it'll be fine. But it won't be, if co2 increased to 4000 ppm quickly enough, humans would not be fine. There were no humans during the time you were describing.
Of course, for earth it doesn't matter at all.
Is not doomsday as the world won't change overnight, but some areas of the globe will suffer a lot from the higher intensity of the weather and this will probably create a lot of global challenges and might bring (mostly) overcome tragedies, like widespread famine, back to the news
When temperature rises slowly, ecosystems adapt in parallel to the change. When temperature rises fast, ecosystems don't. And so we have major die-offs of coral and trees, without corresponding colonization in places where they could now live.
When CO2 rises slowly, the ocean's pH is buffered by large deposits of calcium carbonate on the bottom. When CO2 rises fast, we get ocean acidification, which is on track to be the most extreme shellfish extinction event in the last 50 million years.
Therefore larger absolute past climate changes were less likely to have extreme impacts than faster present climate changes.
https://en.wikipedia.org/wiki/Holocene_extinction
Life will go on. Humans? Maybe. Human civilization will be disrupted for sure
Also: here's a visualization of how fast the climate changed in the last 20000 years vs today
The short term effects are all about the slope. And the short term is all that matter to us, because if we don't pass through this bottleneck we won't have a long term (it may well be our "great filter" preventing us from spreading through the stars)
The problem with this argument is that 'humans' surviving, is different than 'our nice comfortable human society surviving'.
Yes, the human species as an animal that can survive by foraging, probably will survive. That isn't a great argument.
NONE of them happened at anything approaching the RATE of today's anthropogenic warming.
Our climate is warming literally orders of magnitude faster than any previous change. This is overwhelming the ability of ecosystems to adapt.
Moreover, this is entirely preventable — we're doing it, we can stop it.
The concern is, during these hotter/colder periods of earth's existence - what happened to human life during that time?
Did populations decline? Were humans nearly run into extinction?
* 170,000 years ago: humans are wearing clothing by this date.
* 125,000 years ago: the peak of the Eemian interglacial period.
* ~120,000 years ago: possibly the earliest evidence of use of symbols etched onto bone
* 75,000 years ago: Toba Volcano supereruption that may have contributed to human populations being lowered to about 15,000 people
The Eemian climate is believed to have been warmer than the current Holocene. Changes in the Earth's orbital parameters from today (greater obliquity and eccentricity, and perihelion), known as Milankovitch cycles, probably led to greater seasonal temperature variations in the Northern Hemisphere. During the northern summer, temperatures in the Arctic region were about 2-4 °C higher than in 2011.
The hippopotamus was distributed as far north as the rivers Rhine and Thames. . . . The prairie-forest boundary in the Great Plains of the United States lay further west near Lubbock, Texas, whereas the current boundary is near Dallas. . . . Sea level at peak was probably 6 to 9 metres (20 to 30 feet) higher than today . . . .
Given that we're so close to being able to do it, we honestly need a Manhattan project initiative to push it through to reality (with the outcome being the machine and process to do the drilling).
Though as a corollary, such an event would be civilisation-ending in any regard.
It's also ... highly rare. Somewhere in the 1 in a million to 100 million year range, which is to say, not only longer than the planning horizon of most human institutions, but well outside the existence of the human species for the most part.
It's also well beyond the available supply of terrestrially-minable uranium,[1] and possibly of ocean-extracted uranium,[2] and thorium[3]. Breeders might be another option, though I've seen no substantive estimates of total fuel availability for that case either.[4]
But as an argument favouring nuclear over other energy options ... this is pretty silly, really.
About the only viable defence against such a risk would be, and I say this as someone who's markedly pessimistic on space colonisation, independent and self-sufficient habitations off-Earth: YACP.[5]
________________________________
Notes:
1. If we relied on naturally-occurring terrestrially-mined uranium for all present human energy consumption ... supplies would last fewer than two decades. This is seldom mentioned by nuclear advocates.
2. This offers a potentially much larger supply, as uranium is present as a solute in seawater, but viable industrial-scale extraction is unproven and would require filtering vast quantities of seawater.
3. Thorium is reasonably abundant, though I'm not quite sure how abundant. Thorium-based reactors are not much used, and the concept of molten-salt reactors (MSR) which gained some popularity in the past decade ... faces some very significant engineering hurdles. Managing high-temperature highly-corrosive radioactive salts is ... challenging.
4. Breeders produce plutonium. And now you have two, or more, problems.
5. Yet Another Challenging Proposition.
Which is to say: You Will Be Having Bigger Problems.
Recovery from regional meterological catastrophes is well within human capabilities.
I'm honestly a bit shocked.
And what's with the weird tone? It's a super banal point that our food requires sun. I highly doubt you're "shocked" by it.
How can people not generally understand the connection?
https://en.wikipedia.org/wiki/Cerutti_Mastodon_site#Criticis...
This article is much more sympathetic (and also a fun read):
https://www.latimes.com/local/california/la-me-cerutti-masto...
I’m no expert but it seems like this is still a controversial idea.
The usual shallow, reflexive objection is that the bones must have been broken and carefully re-arranged via being run over by construction equipment. This absurd suggestion has been very thoroughly demolished without assistance from construction equipment. It is hard for dump truck tires to produce green-stick fractures in 130,000-year-old bone, or to put bone fragments into the pores of stones and then move them yards away, all while underground.
The key question is: How much CO2 did that super-eruption emit into the atmosphere?
In our hurry to attribute climate change to our meager impact on this planet, we tend to forget what horrors an eruption of this magnitude can cause. And who knows how many of them happened during the past millennia.
We at least have a significantly large list of what we know [1] - that's part of the purpose of core drilling, the ash deposits worldwide can be linked together to estimate where ash traveled to. Also, craters and their surrounding can be drilled into to determine eruption events.
[1] https://en.wikipedia.org/wiki/List_of_large_volcanic_eruptio...
The size and frequency of the largest explosive eruptions on Earth, Mason 2004
https://www.researchgate.net/publication/227000709_The_size_...
I've never found a CO2 estimate, but did find that it's a significant amount of that mass, as is SO2.
It wasn't worth me doing more of a sketch since it's not clear how to model the effects of such a massive system.
I was struck tho, that the magnitude of this and a few other events in the not too distant past, are vastly larger than even all put nuclear war
It's not clear to me that our CO2 emissions are very significant in comparison
<https://en.wikipedia.org/wiki/List_of_largest_volcanic_erupt...>
As for the gaseous component of ejecta:
Water vapour is consistently the most abundant volcanic gas, normally comprising more than 60% of total emissions. Carbon dioxide typically accounts for 10 to 40% of emissions.
<https://en.wikipedia.org/wiki/Volcanic_gas>
Citing: H. Sigurdsson et al. (2000) Encyclopedia of Volcanoes, San Diego, Academic Press.
One of the largest volcanic events I'm aware of is the Siberian Traps eruption, about 250 mya, with a volume of about 4 million km^3, another three orders of magnitude greater than Tomba.
This has been linked to the Permian–Triassic mass extinction event, with the mechanism being release of methane clathrates and/or stimulating growth of a microbe which released vast quantities of methane into the atmosphere, killing ~81% of all extant marine species and 70% of terrestrial vertebrate species.
<https://en.wikipedia.org/wiki/Siberian_Traps>
"The level of atmospheric carbon dioxide rose from around 400 ppm to 2,500 ppm with approximately 3,900 to 12,000 gigatonnes of carbon being added to the ocean-atmosphere system during this period."
-- Wikipedia, citing Wu, Yuyang; Chu, Daoliang; Tong, Jinnan; Song, Haijun; Dal Corso, Jacopo; Wignall, Paul B.; Song, Huyue; Du, Yong; Cui, Ying (9 April 2021). "Six-fold increase of atmospheric pCO2 during the Permian–Triassic mass extinction". Nature Communications. 12 (1): 2137. Bibcode:2021NatCo..12.2137W. doi:10.1038/s41467-021-22298-7.
<https://en.wikipedia.org/wiki/Permian%E2%80%93Triassic_extin...>
Yeah, it's the comparison between DRE and Gas ejecta that got me bogged down before.
Having now given up, I asked ChatG4. It says "the mass ratio between DRE and gaseous emissions might be on the order of 20:1 to 100:1", no citations ofc.
So, just as a strawman and using your 10-40%, on the low end .01.1 = 0.001, high end .05.4 = 0.02. So .1%-2% of ejecta by mass is CO2 emissions. Hah :)
Using my orig figure for Toba of a billion gigatons of ejecta, of which roughly a million gigatons would be CO2. Correct math?
Human GHG emissions are ~50 Gt/year.
Mt St Helens, for example. Not the largest eruption.
But a landslide of approximately 2.5km^3 (over 3 billion cubic yards).
Okay, some say, so that is a lot of earth...
and then you learn that the landslide was moving at speeds of up to 160mph.
That's a LOT of energy.
Geologists. And the answer is "none" for the past 25 or so millenia, and "one" since Toba.
Also, unless you've had supervolcanoes go off in your bedroom and didn't tell anybody, the evidence for human impact is exceedingly clear.
Geologists might know, same as astronomers might know what Black Holes and Pulsars really are.
On the other hand, it is a geologist's call to search for answers and for truth. Saying that they truly know is the same as saying nothing.
Of course the people will feel the local rise of temperature in asphalt-ridden and industry-polluted streets. It's logical.
This does not mean that global climate has changed.
Bottom line: we need large scale carbon capture quickly because even if we reach net zero CO2 will take millenia to drop to the level it was pre-industrial revolution.
We also have a great deal of methane leakage, which is usually cited as 25-100x, and we may soon have a lot of hydrogen leakage, at >100x. Rocket launches are installing water vapor, another one, into the stratosphere like never before.
So even if we got CO2 down to a pre-industrial level, we would still have heat forcing from the fluorine- and other compounds.
Capturing CO2 is kind of pointless until we get emissions under control. I.e., a dollar spent preventing emissions buys much more than a dollar spent capturing. Solar panels and wind turbines directly displace mass emitters of CO2.
On the other hand, as said, CO2 stays for centuries if not 1,000+ years so at this point net zero is only half the job.
Empirically observed, atmospheric CO2 went from ~320ppm to ~410ppm from 1970 to 2020[0], during which period the human population more than doubled from ~3.7B to ~7.8B and yet deaths caused by climate dropped threefold[1] (not 1/3 the rate; 1/3 in absolute number).
[0]: https://www.climate.gov/news-features/understanding-climate/...
Polonium by that ultra-short-relative-term reckoning is not only harmless as it you still feel fine 10 minutes later, but actually healthsome as you rather feel refreshed by the delicious green tea you just drank in that 5-star hotel bar.
We want to return to pre-industrial levels because we’re used to it and we liked it more then.
Scrappy because, well the planet doesn't quite become uninhabitable and we're starting from the end-game. Science fiction also had me expecting some very cool terraforming infrastructure, not psy-ops to get the serfs to eat bugs.
1. https://energyeducation.ca/wiki/images/8/8f/Ice_ages2.gif
A colossal volcanic eruption could do the trick, and those seem to happen rather unnervingly frequently.
The CO2 curve 800000 years back is an excellent example.
CO2 in air bubbles in ice will diffuse into the ice during the many millenia the ice have been stored under pressure. You can therefore expect the ice core CO2 to be lower than hypothetical atmospheric measurements at the same time.
The diffusion is expected to progress fastest at the start, and then more slowly.
Still the artifact is absolutely obvious as the CO2 concentration peaks are lower and lower the further back in time it goes.
Yet of course someone had to splice it all together and not even add error bars.
[0]: https://www.antarcticglaciers.org/glaciers-and-climate/ice-c...
It is well-understood that many ice cores give the same relative shape of peaks of various gasses through time.
Going from there to claiming knowing the absolue concentrations without very large error bars, is just not science.
"Carbon dioxide measurements from older ice in Greenland is less reliable, as meltwater layers have elevated carbon dioxide (CO2 is highly soluble in water)."
https://www.cambridge.org/core/journals/journal-of-glaciolog...
They have found some meltwater layers with unexpectedly large quantities of CO2 > 750ppm.
But they also show that there is unexpected heavy diffusion around the meltwater layers. And they argue very compellingly, that the ice core CO2 records have been smoothed through natural diffusion.
Why is this information not given when showing this graph?
What's the causal explanation behind that much CO2 though? Super-volcano eruptions?
But from the layers around it, it becomes clear that through the years these high CO2 bubbles leak CO2 to nearby layers.
And so CO2 may very well have been just as high as it is currently, but due to changes in the ice, CO2 highs have been lowered and CO2 lows been raised.
The short term solution/bandaid is pumping SO2 into the stratosphere while we figure out carbon capture.
Because it would be expensive, but it would kill several birds with one stone: we (1) prove whether the concept would work on Mars, (2) develop the technology to do it, and (3) unlike SO2 in the atmosphere, "switching it off" or modifying the scale of the effect can be done almost instantly (you could remove the swarm by having it fall back to an Earth orbit).
As a layperson, it's just one more reason I so wish we'd invest in nuclear. Nuclear powered DAC plants might be the only way to scale it fast enough. Sure, it would still be expensive, but that's much cheaper than not massively reducing CO2 in the atmosphere.
Which is why keeping temperature down with SO2 during that time makes sense.
The mechanism is well known from volcanic eruptions, and it only lasts (from memory) 1-2 years in the stratosphere, so if something goes wrong, it can easily be tapered off.
It also shows how crazy it would be if we get the projected 2-3 degrees average temperature increase. Even in a period where we'd expect to be going into a new ice age; instead shooting to a previously unseen high temperature.
Yeah a warmer climate brings all kinds of horrible changes. But food still grows in the northern hemisphere. A colder climate is arguably even worse for us.
By the way, that’s no excuse to keep doing what we’re doing. Limiting warning at 2-3 degrees will be nice. Things get really horrific above 4. At some unknown point feedback cycles really kick in and we go to 5-10 degrees and get completely fucked. We really have to not find out where that threshold is.
The earth varies in distance to the sun and axial tilt and precession. Like waves, there factors can either overlap and somewhat cancel or they can stack for a larger effect.
The time scales for anthropogenic climate change and the previous temperature cycles are so different as to not be comparable.
I’m just saying that a silver lining of the mess we’ve made is that we probably won’t have that ice age in 50,000 years. We’ve likely disrupted the cycle.
I think you are overestimating the probability that humanity would be "long gone by then". Even if a series of catastrophic events + climate change make life as we know it (modern civilization, globalized society/trade) untenable, humans are smart and many places on earth are reasonably forgiving to survival. Not saying it would be comfortable tho.
It’s unclear that it would play out that way. One could look at what happened the last time it stopped to get some idea, but things are different this time. We have a lot more atmospheric CO2.
IPCC predicts some local tipping points at 4C but global tipping points are much higher.