Yes, we're heading back to Pliocene conditions at full tilt, no doubt about it, and the trigger has been pulled, the tipping point is in the past, so better start adapting to these new conditions. Don't buy property in flood zones, or in wildfire zones, or in low-lying coastal hurricane zones, and if you do, expect to evacuate regularly at the very least. However, life was abundant in the Pliocene, so hysteria about 'existential threat' is overblown - at least, it is if we stop using fossil fuels over the next half-century or so. Given the boom in solar led by China, this is entirely feasible.
Climate change and tropical Andean glaciers: Past, present and future
Vuille et al., Earth-Science Reviews 89 (2008) 79–96
> "Temperature in the Andes has increased by approximately 0.1 °C/ decade, with only two of the last 20 years being below the 1961–90 average. Precipitation has slightly increased in the second half of the 20th century in the inner tropics and decreased in the outer tropics. The general pattern of moistening in the inner tropics and drying in the subtropical Andes is dynamically consistent with observed changes in the large-scale circulation, suggesting a strengthening of the tropical atmospheric circulation. Model projections of future climate change in the tropical Andes indicate a continued warming of the tropical troposphere throughout the 21st century, with a temperature increase that is enhanced at higher elevations. By the end of the 21st century, following the SRES A2 emission scenario, the tropical Andes may experience a massive warming on the order of 4.5–5 °C. Predicted changes in precipitation include an increase in precipitation during the wet season and a decrease during the dry season, which would effectively enhance the seasonal hydrological cycle in the tropical Andes."
Well, the degree of "existential threat" depends on whether you're a rich industrialized country at mid-to-high latitudes or not. And even that is conditional on the question of how many hundreds of millions of climate refugees there will be in the next 50 years, and what exactly can be done about them.
A nontrivial fraction of Earth's land area, currently populated by a billion+ humans, will almost certainly become incompatible with such density. No matter how sedentary a part of humanity has become, people will not just sit down and die when conditions become unbearable; they will start walking. I'm reminded of Sagan's poignant words, even if spoken in a much more optimistic context:
Even after 400 generations in villages and cities, we haven't forgotten. [...] has been meticulously crafted by natural selection as an essential element in our survival. Long summers, mild winters, rich harvests, plentiful game—none of them lasts forever. It is beyond our powers to predict the future. Catastrophic events have a way of sneaking up on us, of catching us unaware.
The refugee issue is something that many people have either not thought about at all, or try their best not to think about to avoid cognitive dissonance, or think that it can be solved by building high enough walls and shooting anyone who tries to get through. Even without regard to the practicality of the latter solution, it is morally abhorrent enough to make it incompatible with any reasonable definition of a civilized society. Particularly because it's the rich industrialized societies that are directly responsible for the crisis in the first place!
China is currently directly involved in helping Africa leapfrog the fossil fuel technology that the industrialized West relied on for economic growth. You won't find much about this in the Western corporate media for fairly obvious reasons, but clearly the world can completely eliminate fossil fuel use within 50 years.
My point is this trajectory still absolutely guarantees steady warming at around current rates 0.1 - 0.2 C per decade IIRC for the next several hundred years. All the tech fixes, aerosol injection etc., only mask the issue for a decade or two and are best classified as worthless scams. The only option is adaptation to new conditions, with replacement of fossil fuels with renewables and storage as priority #1.
Of course fossil fuel producers and exporters like the United States, Russia, Venezuela, Saudi Arabia etc. don't want to hear this, but that cash cow is going the way of whale oil and the kerosene lamp, and fast. There will be much howling and gnashing of teeth.
As far as climate refugees, well maybe - but don't underestimate the capability of humans to adapt to new (degraded) conditions. I'd expect a steep decline in birthrate across much of the world as the pressure rises, however.
The tremendous, astronomical injustice of the climate catastrophe is that specifically the societies that are the least responsible for it, and the least able to mitigate and adapt to it, are going to be the worst affected by its consequences.
This is really not as definitive as you claim, although it is a popular talking point. Polar amplification of warming is well-understood, that's where the greatest temperature swings will take place, and that's going to impact Europe, North America, Japan, Russia, etc. heavily. Nobody is going to escape the consequences, it's planet-wide.
Aug 2022 "The Arctic has warmed nearly four times faster than the globe since 1979"
Well I initially thought the same thing (as some rando who put negligible thought or research into it). Then it was pointed out by a science youtuber that mass migration of people is a problem, which I promptly ignored.
However upon reflection, suppose the population of Mexico did try to go north due to drought. Mexico outnumbers the US army by 126:1, so it's definitely not something to dismiss out-of-hand. Also a lot of manufacturing is done there.
So it may not be a "die of heat" type existential threat for people in North America, but it seems plausible that a collapse of the system type existential threat is possible.
Unfortunately it’s not hard to imagine that these pressures are going to cause a huge amount of political instability and dramatically increase the odds of catastrophic conflict though.
it's an existential threat to our way of life, as we know there we be plenty of plants and animals after we're gone just like there were plenty before us
that's not to say that we haven't left a bit of a scar, but even meteor craters fill with time
Also critical, which you failed to notice, is the fact that this anthropogenic-forced climate change is happening 10,000+ times faster than prior unforced climate changes. Changes that took a million years now happen in a mere century.
Systems require time to adapt and this is essentially demanding ecosystems adapt to an explosive shock wave.
When speed increases by orders of magnitude, the phenomena become not only quantitatively different, they are fundamentally different. For example, consider sipping your coffee only 1000x as fast as normal; instead of ~one seconds from table to lip, it's a millisecond. You'll need to accelerate your cup to 2000 fps, almost Mach3, then decelerate it. In is not even close to the same sort of event, considering the required explosive-level forces involved.
Some ecosystems, such as certain bird nesting patterns can move that fast. But others, such as trees with a reproduction cycle of centuries — and the habitats dependent upon them, may be wiped out before their younger generation can establish itself closer to the poles...
With climate change, it really is true that speed kills.
Looking at the scale legend on the photo, this seems like a relatively tiny glacier. What is the significance of it melting away? (I mean, obviously, the smaller the glacier, the easier it melts.)
You are comparing a 2015 picture versus a 2024 picture. It was not a tiny glacier. The glacier you see on that picture I sent was not on Peak Humboldt, it was one of the many other glaciers that covered the Venezuelan Andes.
This is just the final glacier. There's a previous article [0] linked in the piece that shows the decline of multiple glaciers in other areas since 1975.
nah, ice ages come and go with the earths gyroscopic precession. next ice will come as we tilt such that the sun is mostly over the sea through the year.
26,000 year period if I recal correctly, which we are nearly at the end of this phase since the last one finished.
you need a source for land being hotter than water during the day really?
Please dont tell me you need a source to prove it snows in winter.
seasons are caused by the earths tilt, that tilt changes over a 26000 year period, giving ice ages and periods like now, thats like primary school geography.
I know most of the media guys were too busy eating crayons to listen to basics like that in school, but I expected better from here.
Im not worried we won’t survive as a species, but more worried about an imminent population collapse, it has the potential to be catastrophic for a large part of it. And very ugly for the survivors too. It has the potential to alter what it means to be human.
The Bronze Age Collapse (now largely attributed to natural climate change) didn't seem to alter what it means to be human. Iliad and Odyssey portrays normal human beings busy with love, politics and war. Greeks lost almost everything including their writing system, had to pass these poems orally for centuries until a completely different alphabet was invented, and yet nothing changed much in the end. Same for surviving Egyptian texts or the famous "wrong grade of copper" cuneiform tablet.
Given how similar were societies across the globe even before globalization have started, I doubt you'll get something different even from humans on an isolated island if the island can support a big enough population to develop culture.
Yes. Our imagination allows extraordinary levels of doublethink. We know there is crisis underway and yet Nvidia, Microsoft and Apple are the most valuable companies in the world.
End of days was predicted by a nile delta farmer named Billy or Jason about 7256 years ago. It was eventually debunked by a dam.
We'll figure something out when confronted by x catastropha
Yeah we're doing so well at facing this one now. Half the people who might do something about it are still denying it (while updating their air conditioning)
It's a race that we haven't started running yet. By the time we decide to hit the track, it might already be too late to change anything. It's pretty sad that our solution is probably going to end up being "build a colony ship and leave Earth".
Only on HN would I think this is a serious comment.
"We have a problem with the system, that's why we need to apply more of the system as hard as possible!"
That’s just negativity IMO. “Things are hard so we’re definitely doomed for extinction” is... well, at the very least it’s not very scientific.
There are good things too! We recently launched the biggest rocket ever - that was pretty cool. Also we invented computers that can think, which seems likely to be useful! Giving up now would be like giving up in 1924 because corruption was rampant and the Spanish flu was still recent in the mind… our “polio vaccine” or “penicillin” is just around the corner, my friend
No, we didn't. They produce useful text but can't think.
And to create these texts we produce more carbon dioxide in the process.
And not all AI generated text are useful.
Climate change and tropical Andean glaciers: Past, present and future Vuille et al., Earth-Science Reviews 89 (2008) 79–96
> "Temperature in the Andes has increased by approximately 0.1 °C/ decade, with only two of the last 20 years being below the 1961–90 average. Precipitation has slightly increased in the second half of the 20th century in the inner tropics and decreased in the outer tropics. The general pattern of moistening in the inner tropics and drying in the subtropical Andes is dynamically consistent with observed changes in the large-scale circulation, suggesting a strengthening of the tropical atmospheric circulation. Model projections of future climate change in the tropical Andes indicate a continued warming of the tropical troposphere throughout the 21st century, with a temperature increase that is enhanced at higher elevations. By the end of the 21st century, following the SRES A2 emission scenario, the tropical Andes may experience a massive warming on the order of 4.5–5 °C. Predicted changes in precipitation include an increase in precipitation during the wet season and a decrease during the dry season, which would effectively enhance the seasonal hydrological cycle in the tropical Andes."