5/1/2026 at 3:18:34 AM
Most people do not know that we are in an icehouse phase, which is rare.Earth spends most of its time in greenhouse phases.
"A "greenhouse Earth" is a period during which no continental glaciers exist anywhere on the planet... Earth has been in a greenhouse state for about 85% of its history.
"Earth is now in an icehouse state, and ice sheets are present in both poles simultaneously... Earth's current icehouse state is known as the Quaternary Ice Age and began approximately 2.58 million years ago... Earth is expected to continue to transition between glacial and interglacial periods until the cessation of the Quaternary Ice Age and will then enter another greenhouse state."
by chasil
5/1/2026 at 5:21:31 AM
We'll be much closer to a greenhouse earth than a glacial earth if we get that 4°C warming, so the distinction is more academic than practical in most contexts. What's a century here or there in geologic time?by AlotOfReading
5/1/2026 at 6:39:29 AM
The Cambrian and Eocene reached around +14C compared to today[1]. Two of the warmest periods in Earth's history, granted. But life thrived. Governments, private property ownership, civilization, not as battle tested.1: https://en.wikipedia.org/wiki/Geologic_temperature_record#/m...
by timschmidt
5/1/2026 at 1:00:37 PM
Our bodies won't be able to handle a temperature regime that hot overall. The factor to research is Wet Bulb Temperature Effect. Basically our bodies are like sports cars and keeping our body cool is a challange under high humidity with temperature near our body temp.https://www.weather.gov/ict/WBGT
https://www.psu.edu/news/research/story/humans-cant-endure-t...
UNIVERSITY PARK, Pa. — As climate change nudges the global temperature higher, there is rising interest in the maximum environmental conditions like heat and humidity to which humans can adapt. New Penn State research found that in humid climates, that temperature may be lower than previously thought.
It has been widely believed that a 35°C wet-bulb temperature (equal to 95°F at 100% humidity or 115°F at 50% humidity) was the maximum a human could endure before they could no longer adequately regulate their body temperature, which would potentially cause heat stroke or death over a prolonged exposure.
Wet-bulb temperature is read by a thermometer with a wet wick over its bulb and is affected by humidity and air movement. It represents a humid temperature at which the air is saturated and holds as much moisture as it can in the form of water vapor; a person’s sweat will not evaporate at that skin temperature.
But in their new study, the researchers found that the actual maximum wet-bulb temperature is lower — about 31°C wet-bulb or 87°F at 100% humidity — even for young, healthy subjects. The temperature for older populations, who are more vulnerable to heat, is likely even lower.
by Projectiboga
5/1/2026 at 3:45:38 PM
> Our bodies won't be able to handle a temperature regime that hot overall. The factor to research is Wet Bulb Temperature Effect.That's a problem at the Equator, but not at the higher latitudes.
by timschmidt
5/1/2026 at 5:14:29 PM
It's a problem anywhere, just that the dry bulb temperature needed to reach a given wet bulb temperature goes up as humidity goes down.by SAI_Peregrinus
5/1/2026 at 5:20:48 PM
It's a problem anywhere that temperatures reach that high. Higher latitudes have colder climates. Hence, not a problem. If it becomes a problem, people move toward the poles. No longer a problem.Earth would have to experience > +35 to +50C for the poles to be uninhabitable due to heat.
by timschmidt
5/1/2026 at 5:44:32 PM
> Higher latitudes have colder climates.Not reliably, not continually, and much less often when you dump enough energy into the atmosphere to disrupt major wind patterns.
British Columbia hitting 121°F/49.6°C at 50°N latitude would sort of suggest your generalization doesn't hold true anymore.
by clark_dent
5/1/2026 at 5:55:53 PM
Yes, polar regions are reliably colder than equatorial regions. Lytton, BC hit the temperature you cite for one day on Tuesday, June 29, 2021. That's a sign of warming, and we should expect more warm days than in the past at any given lattitude. But it is not evidence against the general case that polar regions have colder climates than equatorial regions.Here's a citation demonstrating that over the last 95 million years if you need one: https://www.pnas.org/doi/10.1073/pnas.2111332119
One more just for fun: https://journals.ametsoc.org/view/journals/clim/12/4/1520-04...
by timschmidt
5/1/2026 at 4:20:31 PM
This explains something about why I haven't understood casually mentioning 40c+ temps, 34c in Hong Kong with no breeze is about as much as I can handle.by interstice
5/1/2026 at 7:34:47 AM
Hmm. I do like civilization. How about humans, would human life thrive?by reverius42
5/1/2026 at 7:39:59 AM
No reason not. It would push human habitable zones into the high mid-latitudes and subpolar regions though. 55–65° N/S would be closest to comfortable temperatures. So, northern Canada and Russia, Greenland, Antarctica.The mad rush to get there would likely extract a heavy toll.
by timschmidt
5/1/2026 at 7:49:17 AM
The main problem is agriculture. If rain patterns get severely disrupted in most of world's current breadbaskets, it takes time to increase production in areas that may now have more favourable climate. During that time lots of people would starve.Rain patterns and extreme weather events are the things to really worry about. Temperature changes alone can be mostly dealt with by planting different crops.
by rwyinuse
5/1/2026 at 7:55:52 AM
Oh, yeah, like even if it's survivable for humanity in general, it's going to kill billions of humans.by reverius42
5/2/2026 at 2:16:05 AM
It’s not just about time to increase production. A lot of crops that grow at lower latitudes won’t have enough time to mature in the short summers of higher latitudes and may suffer from weaker sunlight due to the lower angle resulting in more intervening atmosphere. We might eventually be able to breed or genetically modify crops to be hardier — but the former takes time and the latter requires sufficient remaining civilization and security to support the labs.by apothegm
5/1/2026 at 7:55:25 AM
No doubt the transition period would likely involve more death than most catastrophes in history. In part because there are simply more people. Available sunlight is also less nearer the poles, which already affects agriculture in places like Greenland. Crops would shift. We'd be more dependent on energy and supplemental light for certain crops. Adjustment would be difficult. But quite a bit of land would still be habitable.by timschmidt
5/1/2026 at 1:44:32 PM
Disease and parasitic life would also explode in all previously-habitable parts of the Earth due to increased temp.by Throaway199999
5/1/2026 at 9:46:46 AM
> The mad rush to get there would likely extract a heavy toll.Climate refugee situation will dwarf any war refugee issues. They claim "invasion" now, but this one will be an actual invasion.
by exe34
5/1/2026 at 7:55:25 AM
Interesting. Paying close attention to geopolitics lately, it kind of seems like we're already in a slow-motion mad rush to own these places. Remember when Trump almost invaded Greenland?by reverius42
5/1/2026 at 7:57:28 AM
Certain investment firms purchased cold-weather ports which were iced in 8 months a year, 20 years ago, which now operate nearly year-round.by timschmidt
5/1/2026 at 8:30:05 AM
Sounds like a good long term investment. And maybe not that long term!by reverius42
5/2/2026 at 9:48:56 AM
> Remember when Trump almost invaded Greenland?That one may not be out of the woods yet.
by justinclift
5/1/2026 at 8:58:01 AM
I know civilization sounds appealing but have you considered giant dragonflies?by avadodin
5/1/2026 at 9:40:13 AM
From what I read recently (and I don't remember where it was), the current thinking is that it wasn't oxygen levels or temperatures, but the lack of predators that let dragonflies grow that big. A big dragonfly is much slower and an easier target. So unless you get rid of birds, you won't have giant dragonflies.by VorpalWay
5/1/2026 at 1:04:15 PM
You need high oxygen content in the air though. Insect style circulatory systems aren't efficient enough to get oxygen to the cells without the air having a super high concentration of oxygen to begin with.Basically like how when people can't breath good you put them on oxygen to keep them alive only getting oxygen into the blood is the bottleneck rather than into the body.
by cucumber3732842
5/1/2026 at 7:28:21 AM
[dead]by lukeify
5/1/2026 at 11:13:31 AM
Assume that there will be a mass extinction event somewhere in the next 1000 years - meteor, WW3, whatever. If you'd then play a timelapse of earth, you'd see it on fire, cooling down, oceans forming, greenery forming, continental drift, north/south poles icing over and clearing, snowball (?) earth a few times, then in a short blip the rise and fall of humanity, then uh. more of the same. Geological (and universal) time scales are mind blowing.by Cthulhu_
5/1/2026 at 7:03:08 PM
It's called the Holocene extinction and it's happening right now.by padjo
5/1/2026 at 11:53:24 AM
Yeah, this is also why the "the climate has changed before and will always change" comments are so misleading - indeed it does, and currently, it's in a cold phase, so if we're seeing rapid warming right now, then something is seriously off.by xg15
5/1/2026 at 11:58:29 AM
It is worth pointing out that there is evidence of warming on Mars just now. I don't doubt anthropogenic warming is a thing, but it appears there is a solar factor too.by nephihaha
5/1/2026 at 1:19:37 PM
If this is some kind of attempt to excuse human massive carbon emissions by mis-attributing warming to a broader geological or astro-pysical phenomenon, it completely ignores the insane RATE of warming.The rate of warming in the last century is orders of magnitude faster than any natural geological warming trend. It is the mother of all hockey-stick graphs, conveniently drawn for us by Randall Munroe [0]. Note: you will need too scroll a lot.
by toss1
5/1/2026 at 6:26:27 PM
I've read that, and I wasn't attempting to say anything about human activity.The intention was to draw attention to the grand scope of the earth's history, and the rare climate in which we reside.
by chasil
