9 ms·

What’s the hottest the Earth’s ever been?

58 points by throwaway2474 5y ago

cable2600 5y ago
During the age of dinosaurs it was hotter than it is now.
- beowulfey 5y ago
  Yes, we live in a relatively cold era in the history of our earth. It’s a great, very informative article.
WaxedChewbacca 5y ago
matkoniecz 5y ago
During Hadean geologic eon, when Earth surface was molten and cooled to form the first rocks. https://en.wikipedia.org/wiki/Hadean https://en.wikipedia.org/wiki/Hadean
- bcraven 5y ago
  Yes, the article acknowledges that but also makes the point that it's not interesting from a human perspective. "None of these techniques help with the very early Earth. During the time known as the Hadean (yes, because it was like Hades), Earth’s collisions with other large planetesimals in our young solar system—including a Mars-sized one whose impact with Earth likely created the Moon—would have melted and vaporized most rock at the surface. Because no rocks on Earth have survived from so long ago, scientists have estimated early Earth conditions based on observations of the Moon and on astronomical models. Following the collision that spawned the Moon, the planet was estimated to have been around 2,300 Kelvin (3,680°F)." "Even after collisions stopped, and the planet had tens of millions of years to cool, surface temperatures were likely more than 400° Fahrenheit. Zircon crystals from Australia, only about 150 million years younger than the Earth itself, hint that our planet may have cooled faster than scientists previously thought. Still, in its infancy, Earth would have experienced temperatures far higher than we humans could possibly survive." "But suppose we exclude the violent and scorching years when Earth first formed. When else has Earth’s surface sweltered?"
melling 5y ago
“For most of the time, global temperatures appear to have been too warm (red portions of line) for persistent polar ice caps. The most recent 50 million years are an exception”
- egberts1 5y ago
  Our Sun probably ate a planet thereby disrupting the solar cycle.
egberts1 5y ago
I often wonder about terraforming (on places like Mars planet). Earth obviously had the leg up on water accumulation during its accretation stage (Hadean period). Perhaps we can start generating oxygen early over there on Mars using a one-step CO2->O2+C catalyst. This comes to mind: https://www.pnas.org/content/109/39/15606 https://www.pnas.org/content/109/39/15606
- skywal_l 5y ago
  I wonder if terraforming is possible, not because of technological limitations but just because of the limitation of humanity's ability to execute such large scale projects. Given an unlimited amount of raw materials and energy, terraforming a planet like mars would probably take decades (centuries?). Private funded projects usually have a TTL of a couple of months to at best 4/5 years and are driven by short to medium term profits. Public funded projects are on a longer timeframe. Taking a recent example, according to Wikipedia, "serious planning" for James Webb started in early 90s. So that's ~30 years. But do we have example, in modern times, of project lasting more than a century? I have Notre-Dame in mind, any other? The construction of Notre-Dame was driven by religious fervor. I wonder if we could muster the same amount of will based only on a profit motive.
  - matkoniecz 5y ago
    Sagrada Família is under active construction since 1882, 139 years ago (with some pauses due to civil war etc). https://en.wikipedia.org/wiki/Sagrada_Fam%C3%ADlia https://en.wikipedia.org/wiki/Sagrada_Fam%C3%ADlia (it is much better inside than outside)
    - eCa 5y ago
      As awesome as it is[1], I don’t think it is ’based only on a profit motive’ as the gp implied they were looking for. [1] Both the building and the project.
- isoprophlex 5y ago
  There's like... six millibars of pressure on mars? Admittedly almost all of those six millibars are CO2, but still. Turning all that into O2 might still not support ~photosynthesis~ bootstrapping plant life, let alone humans breathing. Edit: also sorry to be a party pooper but I studied organocatalysis for a while and you must understand that these research papers about catalysts are almost always so incredibly far away from industrial viability. The ligands take long to prepare, the metals are expensive... and whilst these things might be solvable with enough money, the fact remains that they have turnover numbers that are finite. (The TON is the amount of substrate the catalyst can transform before becoming deactivated) Even with a TON of 1.000 (paper quotes < 10) you'd be able to produce 1.000 moles (32 kg) of O2 from one mole (has 100 g Ru, 2000 USD) of this expensive ruthenium gizmo. Oh and it's an electrocatalyst so better get some planet-scale power generation in place, first.
iqanq 5y ago
Helmut10001 5y ago
It is strange why many politicians and countries (Germany included) appear to close their eyes and still promote or work on the 1.5 °C goal, which seems pretty unrealistic at this stage. Maybe it is to calm the public, besides knowing better. Instead, there is a need for more realistic plans to model and prepare for 3°C or 5°C increase of average temperature by 2060 (or 2100). Looking at these bigger swings in temperature, it is more likely that we're seeing temperature peaking beyond our expectations than below.
- samwillis 5y ago
  Trouble is most politicians are incentivised to think in the short term and are increasing just in a perpetual campaigning mode. They are thinking about their careers and re-election. They cannot except and talk about bad news, and a 3-5degC increase is bad news. On top of that you have had climate activists pushing for very large change to happen incredibly quickly (arguably needed). But it’s an incredibly hard sell to the public who won’t except a negative impact on their quality of life. Basically: 1. People are unwilling to make changes that they perceive as being a net negative to their quality of life. 2. Businesses are unwilling to make changes that they expect to have a net negative to their bottom line. 3. Politicians are unwilling to ask for either of the above to happen because they want to be re-elected.
  - dav_Oz 5y ago
    Update after 2 years of 'crisis management': The social fabric of the western societies had been severely damaged. Trust in science is at an all time low. The absurdly rich are absurdly richer. Not few people are now flirting openly with the idea to simply abandon those bulky civil liberties of the 20th century (2nd half) in order to save the world in the long run. So, in order to satisfy 2. ("green washing") and 3. ("emergency state") 1. (civil liberties) is the obvious pawn "sacrifice".
    - thatguy0900 5y ago
      I don't know how fair it is to bring the last two years up. Our society was no closer in 2018 to solving climate change.
gorpovitch 5y ago
It is interesting to keep these numbers in mind, but these facts are not sufficient to think correctly about climate. The earth is a dynamic system, and the rate of temperature growth is as much, if not more, important than temperature average here. A car going from 100 to 0 kmph in 15 seconds is definitely not the same as a car going from 100 to 0 kmph in 0.1 seconds in terms of damage. the temperature rises described in the article (e.g. during the eocene) are about a few degrees every few hundreds of thousands of years. Flore and fauna had time to evolve. Today we are talking about 4 degrees in less than a hundred years. That's more than thousand times faster.
- dalmo3 5y ago
  Without any knowledge in the field I wonder if the timescale difference could be attributed to the measurement methods used for the last centuries vs literal ages ago. I.e. if we (or someone a million years from now) tried to estimate the 21th century's temperatures using the same techniques used to estimate temperatures a million years ago, would we be able to detect that 4 degree change? Conversely, can scientists today detect or rule out that there was an outlier century a million years ago in which temps varied as much as today?
  - have_faith 5y ago
    > would we be able to detect that 4 degree change? I'm far from an expert on this. Assumedly the damage we are seeing currently and expecting in the near future due to our current warming would be detecteble over a a very large time scale. We seem to be able to detect much more subtle changes going very far back with our current techniques.
  - WithinReason 5y ago
    This is a great question, and it seems that our methods can't detect temperature variation in past data that's similar to the recent rise. See the bottom answer: https://earthscience.stackexchange.com/questions/8746/is-this-xkcd-comic-an-accurate-timeline-of-the-earths-average-temperature https://earthscience.stackexchange.com/questions/8746/is-thi...
MichaelZuo 5y ago
On the positive side of things, northern cities of the world will likely not be buried under an ice sheet anytime soon.
- tim333 5y ago
  That's a relief. I'm old enough to have gone through the 1970s global cooling scare stories https://en.wikipedia.org/wiki/Global_cooling https://en.wikipedia.org/wiki/Global_cooling
tamaharbor 5y ago
Instead of trying to stop the changes (which is probably impossible), why don’t we focus on adapting to what will inevitably become the new normals.
- Tagbert 5y ago
  The efforts are to reduce the degree of change. Full on stop is not likely at point. Adaptation will be even more expensive, but we still get people complaining that efforts to head off climate change are too expensive.
tim333 5y ago
I like to see stuff like this published that gives some hope that a bit of warming in the next century or two is probably not going to lead to a "we're all going to die" situation.
mrlonglong 5y ago
Interesting article, but one thing let it down, it didn't give the Celsius equivalent for the temperatures quoted in Fahrenheit, I think it would have been nice to have those in brackets for those who can't quite make the mental contortions converting from one to the other. Apart from that quite fascinating to see that life did find a way to exist in temperatures higher then today or in the past.

58 points by throwaway2474 5y ago

cable2600 5y ago

During the age of dinosaurs it was hotter than it is now.

beowulfey 5y ago
Yes, we live in a relatively cold era in the history of our earth. It’s a great, very informative article.

WaxedChewbacca 5y ago

matkoniecz 5y ago

During Hadean geologic eon, when Earth surface was molten and cooled to form the first rocks. https://en.wikipedia.org/wiki/Hadean https://en.wikipedia.org/wiki/Hadean

bcraven 5y ago
Yes, the article acknowledges that but also makes the point that it's not interesting from a human perspective. "None of these techniques help with the very early Earth. During the time known as the Hadean (yes, because it was like Hades), Earth’s collisions with other large planetesimals in our young solar system—including a Mars-sized one whose impact with Earth likely created the Moon—would have melted and vaporized most rock at the surface. Because no rocks on Earth have survived from so long ago, scientists have estimated early Earth conditions based on observations of the Moon and on astronomical models. Following the collision that spawned the Moon, the planet was estimated to have been around 2,300 Kelvin (3,680°F)." "Even after collisions stopped, and the planet had tens of millions of years to cool, surface temperatures were likely more than 400° Fahrenheit. Zircon crystals from Australia, only about 150 million years younger than the Earth itself, hint that our planet may have cooled faster than scientists previously thought. Still, in its infancy, Earth would have experienced temperatures far higher than we humans could possibly survive." "But suppose we exclude the violent and scorching years when Earth first formed. When else has Earth’s surface sweltered?"

melling 5y ago

“For most of the time, global temperatures appear to have been too warm (red portions of line) for persistent polar ice caps. The most recent 50 million years are an exception”

egberts1 5y ago
Our Sun probably ate a planet thereby disrupting the solar cycle.

egberts1 5y ago

I often wonder about terraforming (on places like Mars planet). Earth obviously had the leg up on water accumulation during its accretation stage (Hadean period). Perhaps we can start generating oxygen early over there on Mars using a one-step CO2->O2+C catalyst. This comes to mind: https://www.pnas.org/content/109/39/15606 https://www.pnas.org/content/109/39/15606

skywal_l 5y ago
I wonder if terraforming is possible, not because of technological limitations but just because of the limitation of humanity's ability to execute such large scale projects. Given an unlimited amount of raw materials and energy, terraforming a planet like mars would probably take decades (centuries?). Private funded projects usually have a TTL of a couple of months to at best 4/5 years and are driven by short to medium term profits. Public funded projects are on a longer timeframe. Taking a recent example, according to Wikipedia, "serious planning" for James Webb started in early 90s. So that's ~30 years. But do we have example, in modern times, of project lasting more than a century? I have Notre-Dame in mind, any other? The construction of Notre-Dame was driven by religious fervor. I wonder if we could muster the same amount of will based only on a profit motive.
- matkoniecz 5y ago
  Sagrada Família is under active construction since 1882, 139 years ago (with some pauses due to civil war etc). https://en.wikipedia.org/wiki/Sagrada_Fam%C3%ADlia https://en.wikipedia.org/wiki/Sagrada_Fam%C3%ADlia (it is much better inside than outside)
  - eCa 5y ago
    As awesome as it is[1], I don’t think it is ’based only on a profit motive’ as the gp implied they were looking for. [1] Both the building and the project.
isoprophlex 5y ago
There's like... six millibars of pressure on mars? Admittedly almost all of those six millibars are CO2, but still. Turning all that into O2 might still not support ~photosynthesis~ bootstrapping plant life, let alone humans breathing. Edit: also sorry to be a party pooper but I studied organocatalysis for a while and you must understand that these research papers about catalysts are almost always so incredibly far away from industrial viability. The ligands take long to prepare, the metals are expensive... and whilst these things might be solvable with enough money, the fact remains that they have turnover numbers that are finite. (The TON is the amount of substrate the catalyst can transform before becoming deactivated) Even with a TON of 1.000 (paper quotes < 10) you'd be able to produce 1.000 moles (32 kg) of O2 from one mole (has 100 g Ru, 2000 USD) of this expensive ruthenium gizmo. Oh and it's an electrocatalyst so better get some planet-scale power generation in place, first.

iqanq 5y ago

Helmut10001 5y ago

It is strange why many politicians and countries (Germany included) appear to close their eyes and still promote or work on the 1.5 °C goal, which seems pretty unrealistic at this stage. Maybe it is to calm the public, besides knowing better. Instead, there is a need for more realistic plans to model and prepare for 3°C or 5°C increase of average temperature by 2060 (or 2100). Looking at these bigger swings in temperature, it is more likely that we're seeing temperature peaking beyond our expectations than below.

samwillis 5y ago
Trouble is most politicians are incentivised to think in the short term and are increasing just in a perpetual campaigning mode. They are thinking about their careers and re-election. They cannot except and talk about bad news, and a 3-5degC increase is bad news. On top of that you have had climate activists pushing for very large change to happen incredibly quickly (arguably needed). But it’s an incredibly hard sell to the public who won’t except a negative impact on their quality of life. Basically: 1. People are unwilling to make changes that they perceive as being a net negative to their quality of life. 2. Businesses are unwilling to make changes that they expect to have a net negative to their bottom line. 3. Politicians are unwilling to ask for either of the above to happen because they want to be re-elected.
- dav_Oz 5y ago
  Update after 2 years of 'crisis management': The social fabric of the western societies had been severely damaged. Trust in science is at an all time low. The absurdly rich are absurdly richer. Not few people are now flirting openly with the idea to simply abandon those bulky civil liberties of the 20th century (2nd half) in order to save the world in the long run. So, in order to satisfy 2. ("green washing") and 3. ("emergency state") 1. (civil liberties) is the obvious pawn "sacrifice".
  - thatguy0900 5y ago
    I don't know how fair it is to bring the last two years up. Our society was no closer in 2018 to solving climate change.

gorpovitch 5y ago

It is interesting to keep these numbers in mind, but these facts are not sufficient to think correctly about climate. The earth is a dynamic system, and the rate of temperature growth is as much, if not more, important than temperature average here. A car going from 100 to 0 kmph in 15 seconds is definitely not the same as a car going from 100 to 0 kmph in 0.1 seconds in terms of damage. the temperature rises described in the article (e.g. during the eocene) are about a few degrees every few hundreds of thousands of years. Flore and fauna had time to evolve. Today we are talking about 4 degrees in less than a hundred years. That's more than thousand times faster.

dalmo3 5y ago
Without any knowledge in the field I wonder if the timescale difference could be attributed to the measurement methods used for the last centuries vs literal ages ago. I.e. if we (or someone a million years from now) tried to estimate the 21th century's temperatures using the same techniques used to estimate temperatures a million years ago, would we be able to detect that 4 degree change? Conversely, can scientists today detect or rule out that there was an outlier century a million years ago in which temps varied as much as today?
- have_faith 5y ago
  > would we be able to detect that 4 degree change? I'm far from an expert on this. Assumedly the damage we are seeing currently and expecting in the near future due to our current warming would be detecteble over a a very large time scale. We seem to be able to detect much more subtle changes going very far back with our current techniques.
- WithinReason 5y ago
  This is a great question, and it seems that our methods can't detect temperature variation in past data that's similar to the recent rise. See the bottom answer: https://earthscience.stackexchange.com/questions/8746/is-this-xkcd-comic-an-accurate-timeline-of-the-earths-average-temperature https://earthscience.stackexchange.com/questions/8746/is-thi...

MichaelZuo 5y ago

On the positive side of things, northern cities of the world will likely not be buried under an ice sheet anytime soon.

tim333 5y ago
That's a relief. I'm old enough to have gone through the 1970s global cooling scare stories https://en.wikipedia.org/wiki/Global_cooling https://en.wikipedia.org/wiki/Global_cooling

tamaharbor 5y ago

Instead of trying to stop the changes (which is probably impossible), why don’t we focus on adapting to what will inevitably become the new normals.

Tagbert 5y ago
The efforts are to reduce the degree of change. Full on stop is not likely at point. Adaptation will be even more expensive, but we still get people complaining that efforts to head off climate change are too expensive.

tim333 5y ago

I like to see stuff like this published that gives some hope that a bit of warming in the next century or two is probably not going to lead to a "we're all going to die" situation.

mrlonglong 5y ago

Interesting article, but one thing let it down, it didn't give the Celsius equivalent for the temperatures quoted in Fahrenheit, I think it would have been nice to have those in brackets for those who can't quite make the mental contortions converting from one to the other. Apart from that quite fascinating to see that life did find a way to exist in temperatures higher then today or in the past.