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."
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?
timschmidt 1 hours ago [-]
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.
Hmm. I do like civilization. How about humans, would human life thrive?
timschmidt 2 minutes ago [-]
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.
Just as a thought experiment, what would be worse for humanity. Global warming or global cooling by the same amount of degrees C?
I'm in western Europe and really hope the AMOC will not collapse.
timschmidt 3 hours ago [-]
Global cooling could be worse. But the danger from either comes from the speed with which it happens, and inflexible sociopolitical structures, more than the absolute difference in temperature. Rapid change doesn't permit gradual adaptation like relocation to more habitable areas. The danger from the current global warming trend comes from it's incredible rapidity compared to historical trends.
Given time, humans and other animals will move toward the poles or toward the equator to find habitable zones. Put that on a rush schedule and everyone suffers.
arjunchint 2 hours ago [-]
there are no guarantees in life, can look up any random day and see a meteor streaking across the sky and realize that this is the end regardless of "sociopolitical structures".
All that matters is sociotechnological progress to be able to progress further enough to overcome these tests of existence.
timschmidt 2 hours ago [-]
> look up any random day and see a meteor streaking across the sky
That's happened rather more times in Earth's history than most folks are comfortable admitting. Tunguska would have leveled any major metropolitan city on the planet. I still think an impact is one of the more likely initiators of the Younger Dryas abrupt cooling and worldwide ~100M sealevel rise ~12,000 years ago. Conspicuously aligned with the oldest surviving traces of city living, agriculture, etc. It's increasingly accepted that a large portion of human history is 100M underwater on the continental shelves, estuaries, and other coastal areas where humans would have liked to live.
vkou 1 hours ago [-]
Sea level rise was much faster before the cooling of the Younger Dryas.
It's possible the sea level rise could have initiated the cooling. But there is much disagreement as to what exactly initiated the de-glaciation which caused the sealevel rise.
The Lithos Carbon idea is interesting. The mine they show looks like they can just scrape it rather than needing to mine it with explosives. Unfortunately the site's blog has 1 post and it is 3.5 years old. Is it still a going concern?
chris_va 7 hours ago [-]
It's really the alkalinity (e.g. the Mg++ or Ca++), which silicate rocks often have (but technically not limited to silicates).
As an aside, we need to dissolve roughly one large mountain into the mix layer (top ~50m) of the ocean to have it fully take up atmospheric CO2. Without dissolving, the reaction is very slow (co2 in atmosphere => slightly lower pH rain => reaction with mostly passivated rock + erosion).
russearyus 5 hours ago [-]
[dead]
Rendered at 07:41:51 GMT+0000 (Coordinated Universal Time) with Vercel.
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."
https://en.wikipedia.org/wiki/Greenhouse_and_icehouse_Earth
1: https://en.wikipedia.org/wiki/Geologic_temperature_record#/m...
I'm in western Europe and really hope the AMOC will not collapse.
Given time, humans and other animals will move toward the poles or toward the equator to find habitable zones. Put that on a rush schedule and everyone suffers.
All that matters is sociotechnological progress to be able to progress further enough to overcome these tests of existence.
That's happened rather more times in Earth's history than most folks are comfortable admitting. Tunguska would have leveled any major metropolitan city on the planet. I still think an impact is one of the more likely initiators of the Younger Dryas abrupt cooling and worldwide ~100M sealevel rise ~12,000 years ago. Conspicuously aligned with the oldest surviving traces of city living, agriculture, etc. It's increasingly accepted that a large portion of human history is 100M underwater on the continental shelves, estuaries, and other coastal areas where humans would have liked to live.
It's possible the sea level rise could have initiated the cooling. But there is much disagreement as to what exactly initiated the de-glaciation which caused the sealevel rise.
silicate rocks basically traps co2 over millions of years and causes temperatures to fall
https://www.lithoscarbon.com/
https://en.wikipedia.org/wiki/Carbfix
https://co2crc.com.au/
https://sgeas.unimelb.edu.au/research/carbon-trap-lab
As an aside, we need to dissolve roughly one large mountain into the mix layer (top ~50m) of the ocean to have it fully take up atmospheric CO2. Without dissolving, the reaction is very slow (co2 in atmosphere => slightly lower pH rain => reaction with mostly passivated rock + erosion).