Yup.
And we in an Ice Age.
Also called an ice house global climate.
Ice house climates have cold ocean [our average
ocean temp is about 3.5 C] and a drier world with
lots of desert [more 1/3 of land is deserts].
A warmer world has warmer ocean, and warmer ocean
causes higher global vapor, so, less deserts.
The End of World is suppose to arrive when our ocean is 4 C.
What effect is caused by having an Ocean +.5 C warmer. Well apparently our ocean has warmed by about .05 C.
Though in the Little Ice Age the ocean may cooled by .1 C.
I think it has warmed up by about .1 C since coolest ocean got during the centuries of the Little Ice Age.
But what happens if ocean could somehow warm by .5 C?
End of World, ice free polar sea ice in the summer, and a lot polar sea ice in the winter.
This would large effect upon Northern Hemisphere.
The southern hemisphere polar sea ice has been growing, but it still has ice free polar sea ice in summer. Or said differently Arctic ocean has older polar sea ice, Antarctic has very little, Though Antarctic has it’s ice sheet going into ocean {land formed ice- as does the Arctic}.
Anyhow having less of Arctic ocean frozen during the winter means a less cold and less dry Arctic ocean surface which effects the land around it,
Or causes significant polar amplification- Russia and Canada have less cold winters, though they could have significantly more snow and rain.
So in these dry northern regions, one could get a crazy amount of snow and also more rain.
And days of -50 C weather, end.
When the National Park Service pushed to import Canadian Wolves into Yellowstone, one of their prime “arguments” was “to restore the ecosystem”. Restore to what state? Never actually specified.* Now it appears, decades later, it got “restored” to a state that was never before observed or predicted by all the biologist “experts”. Welcome to the Law of Unintended Consequences.
* I once suggested that they push to restore it to the way it was 20,000 years ago, when the area was covered in ice hundreds of feet deep.
“I once suggested that they push to restore it to the way it was 20,000 years ago, when the area was covered in ice hundreds of feet deep.”
“We narrowly missed a new ice age, and now we won’t see one for a long time Before fossil fuels rendered this moot, conditions were nearly right.”
“The researchers conclude that we narrowly missed an ice age off-ramp in the past few thousand years because CO2 was just a touch too high. Lower the concentration by just 40 parts per million in the model, and ice sheets would already be growing by now—though the fossil fuel revolution would still be dictating a planetary U-turn.”
“There’s a debate among climate scientists about whether the advent of agriculture and deforestation had a significant impact thousands of years ago, forestalling the beginning of an ice age as a result.”
Most of the last several million year mother Earth has been in a period of almost perpetual ice ages lasting many 10’s of thousands of years interspersed with relatively brief interglacial periods of 10-20K years (like what we are in now). The advent of Homo Sapiens agricultural revolution probably prevented our over due next ice age. A kind of crude unintended “climate engineering”.
I doubt the next ice age was overdue. It has only been 11,000 years or so since the last one definitively ended. The process only began 20,000 years ago. There also weren’t all that many people, lots of them lived in the tropics. Can’t see there were enough to deforest much although the Australian aborigines did a pretty thorough job of making our megafauna extinct and burned the place almost to the ground. They are now regarded as “custodians of the land”. Barf.
It might be a good idea to restore Chicago to the state it was in 20,000 years ago. A mile of ice will do wonders for the place.
Native Americans used fire to change landscapes too.
“I doubt the next ice age was overdue. It has only been 11,000 years or so since the last one definitively ended.”
The “inflexion point” was only a few thousands years ago the article isn’t that specific as to the date. It could easily have been several thousands of years after the start of large scale agriculture by humans. They are suggesting that even a modest contribution of CO2 by humans at that critical point was enough to stave off the ice age. By the time of the birth of Christ I believe the human population had grown to around ~250 million (from about 5 million 10K years ago.) And also not only agriculture but if things started getting cold around that time people around the world would have almost certainly have been burning increasing amounts of wood/peat etc. to stay warm generating additional CO2 added to the agricultural contribution.
“The researchers conclude that we narrowly missed an ice age off-ramp in the past few thousand years because CO2 was just a touch too high. Lower the concentration by just 40 parts per million in the model,”
There is so much speculation that no one should take any of it seriously. Interesting to ponder but not something to take seriously because what we know about the past changes quite a bit.
Geologists have a lot more humility in what they claim to know and are willing to change their beliefs as more is learned.
We don’t even know how many humans were alive during the last period of glaciation as many of their settlements would be in places currently underwater. Humans have existed in their present form for at least 300,000 years and it is safe to assume they were burning all kinds of things.
Don’t forget the Younger Dryas, which is a very, very weird brief glacial. Nobody has successfully explained it, but my money is on the impact hypothesis (it’s the romantic in me).
If you eliminate that, it’s a bit more like 13 kyr and that’s getting uncomfortably close to the length of your typical interglacial.
I think the clearer oncoming threat is that North America is going to slam into Asia due to ongoing plate tectonics. Few Japanese or West Coasters will survive the resulting vulcanism and mountain uplift.
We must start preparing now, before it’s too late to take action.
It is something to worry about considering the effects of Mexico crashing into the PNW.
Precession plus orbital shape changes have put us at the point where we could slip into a glacial period at any time. The idea that we were saved by rising CO2 is probably a fairy tale. CO2 does not appear to modulate us getting into a glacial, but it does seem to be the main contributor to getting out of one, and it’s by an unusual mechanism.
I really like the Ellis and Palmer hypothesis that getting INTO a glacial period is determined by a Milankovic cycle where the N. hemisphere has shorter (oddly, hotter) summers and ice can accumulate in N. Canada. Never misses. But getting OUT of a glacial and into an interglacial is a more difficult process. The positive feedback from ice covering the north is just too difficult to overcome and it takes several “warm” cycles to snap out of the glaciation. The oceans keep getting colder and colder, sucking CO2 out of the atmosphere until it drops below ~200ppm.
That’s when the magic happens. Vegetation starts dying off from CO2 starvation, even C4 grasses that evolved to handle our relatively low CO2 levels. This leads to dust storms, and the dust is deposited on the glaciers. Then the next time a warm cycle comes by, the lower albedo helps to melt the glaciers and we wind up in an interglacial, for ~10-15 kyr or so. However, the next cold cycle leads to a glacial period. I’m not sure owning an SUV will save you.
So watch out for reports that snow cover in N. Quebec doesn’t melt one summer. That’s the sign that things can go very bad, very quickly. Maybe we can prevent it, but it will take more than cars to do it.
Someone proposed a very interesting idea over at Judith Curry’s blog, which was that agriculture wasn’t practiced until CO2 levels recovered because plants wouldn’t be as productive.
I expanded on that thought a bit, noting that in the earliest agricultural societies, and for millennia thereafter, farming was barely break-even because the early farming populations could only support a small percentage of non-farmers, and could only do so reliably in the especially rich areas where civilization eventually took off, such as the Nile valley and Fertile Crescent.
If primitive farming at the higher, post-glaciation CO2 levels was barely above break-even, farming at lower CO2 levels likely wouldn’t pay off at all, so hunting and gathering would’ve been a better strategy.
The question it raises is whether we weren’t farming because we weren’t smart enough to farm, or whether we weren’t farming because we were smart enough not to, given the primitive tools and methods available, lower overall plant productivity, and paucity of crops that had been improved by generations of domestication.
“If primitive farming at the higher, post-glaciation CO2 levels was barely above break-even, farming at lower CO2 levels likely wouldn’t pay off at all, so hunting and gathering would’ve been a better strategy.”
It was several thousand years after the end of the last ice age ~11K ago before we started large scale agriculture in the fertile crescent. Once it took off the human population blew up; more people equals more fires set to clear land, cook food, general warmth/comfort etc. All of which would cause the CO2 levels to increase modestly over millennia or so of our doing so. Perhaps (maybe) forestalling the beginnings of the next inflection point to flip into another ice age; don’t how long it typically takes before a cold snap becomes full blown cascade to another ice age.
Yup.
And we in an Ice Age.
Also called an ice house global climate.
Ice house climates have cold ocean [our average
ocean temp is about 3.5 C] and a drier world with
lots of desert [more 1/3 of land is deserts].
A warmer world has warmer ocean, and warmer ocean
causes higher global vapor, so, less deserts.
The End of World is suppose to arrive when our ocean is 4 C.
What effect is caused by having an Ocean +.5 C warmer. Well apparently our ocean has warmed by about .05 C.
Though in the Little Ice Age the ocean may cooled by .1 C.
I think it has warmed up by about .1 C since coolest ocean got during the centuries of the Little Ice Age.
But what happens if ocean could somehow warm by .5 C?
End of World, ice free polar sea ice in the summer, and a lot polar sea ice in the winter.
This would large effect upon Northern Hemisphere.
The southern hemisphere polar sea ice has been growing, but it still has ice free polar sea ice in summer. Or said differently Arctic ocean has older polar sea ice, Antarctic has very little, Though Antarctic has it’s ice sheet going into ocean {land formed ice- as does the Arctic}.
Anyhow having less of Arctic ocean frozen during the winter means a less cold and less dry Arctic ocean surface which effects the land around it,
Or causes significant polar amplification- Russia and Canada have less cold winters, though they could have significantly more snow and rain.
So in these dry northern regions, one could get a crazy amount of snow and also more rain.
And days of -50 C weather, end.
When the National Park Service pushed to import Canadian Wolves into Yellowstone, one of their prime “arguments” was “to restore the ecosystem”. Restore to what state? Never actually specified.* Now it appears, decades later, it got “restored” to a state that was never before observed or predicted by all the biologist “experts”. Welcome to the Law of Unintended Consequences.
* I once suggested that they push to restore it to the way it was 20,000 years ago, when the area was covered in ice hundreds of feet deep.
“I once suggested that they push to restore it to the way it was 20,000 years ago, when the area was covered in ice hundreds of feet deep.”
“We narrowly missed a new ice age, and now we won’t see one for a long time Before fossil fuels rendered this moot, conditions were nearly right.”
“The researchers conclude that we narrowly missed an ice age off-ramp in the past few thousand years because CO2 was just a touch too high. Lower the concentration by just 40 parts per million in the model, and ice sheets would already be growing by now—though the fossil fuel revolution would still be dictating a planetary U-turn.”
“There’s a debate among climate scientists about whether the advent of agriculture and deforestation had a significant impact thousands of years ago, forestalling the beginning of an ice age as a result.”
https://arstechnica.com/science/2016/01/we-narrowly-missed-a-new-ice-age-and-now-we-wont-see-one-for-a-long-time/
Most of the last several million year mother Earth has been in a period of almost perpetual ice ages lasting many 10’s of thousands of years interspersed with relatively brief interglacial periods of 10-20K years (like what we are in now). The advent of Homo Sapiens agricultural revolution probably prevented our over due next ice age. A kind of crude unintended “climate engineering”.
I doubt the next ice age was overdue. It has only been 11,000 years or so since the last one definitively ended. The process only began 20,000 years ago. There also weren’t all that many people, lots of them lived in the tropics. Can’t see there were enough to deforest much although the Australian aborigines did a pretty thorough job of making our megafauna extinct and burned the place almost to the ground. They are now regarded as “custodians of the land”. Barf.
It might be a good idea to restore Chicago to the state it was in 20,000 years ago. A mile of ice will do wonders for the place.
Native Americans used fire to change landscapes too.
“I doubt the next ice age was overdue. It has only been 11,000 years or so since the last one definitively ended.”
The “inflexion point” was only a few thousands years ago the article isn’t that specific as to the date. It could easily have been several thousands of years after the start of large scale agriculture by humans. They are suggesting that even a modest contribution of CO2 by humans at that critical point was enough to stave off the ice age. By the time of the birth of Christ I believe the human population had grown to around ~250 million (from about 5 million 10K years ago.) And also not only agriculture but if things started getting cold around that time people around the world would have almost certainly have been burning increasing amounts of wood/peat etc. to stay warm generating additional CO2 added to the agricultural contribution.
“The researchers conclude that we narrowly missed an ice age off-ramp in the past few thousand years because CO2 was just a touch too high. Lower the concentration by just 40 parts per million in the model,”
There is so much speculation that no one should take any of it seriously. Interesting to ponder but not something to take seriously because what we know about the past changes quite a bit.
Geologists have a lot more humility in what they claim to know and are willing to change their beliefs as more is learned.
We don’t even know how many humans were alive during the last period of glaciation as many of their settlements would be in places currently underwater. Humans have existed in their present form for at least 300,000 years and it is safe to assume they were burning all kinds of things.
Don’t forget the Younger Dryas, which is a very, very weird brief glacial. Nobody has successfully explained it, but my money is on the impact hypothesis (it’s the romantic in me).
If you eliminate that, it’s a bit more like 13 kyr and that’s getting uncomfortably close to the length of your typical interglacial.
I think the clearer oncoming threat is that North America is going to slam into Asia due to ongoing plate tectonics. Few Japanese or West Coasters will survive the resulting vulcanism and mountain uplift.
We must start preparing now, before it’s too late to take action.
I agree, George. It’s kind of like this: https://youtu.be/y_PrZ-J7D3k
It is something to worry about considering the effects of Mexico crashing into the PNW.
Precession plus orbital shape changes have put us at the point where we could slip into a glacial period at any time. The idea that we were saved by rising CO2 is probably a fairy tale. CO2 does not appear to modulate us getting into a glacial, but it does seem to be the main contributor to getting out of one, and it’s by an unusual mechanism.
I really like the Ellis and Palmer hypothesis that getting INTO a glacial period is determined by a Milankovic cycle where the N. hemisphere has shorter (oddly, hotter) summers and ice can accumulate in N. Canada. Never misses. But getting OUT of a glacial and into an interglacial is a more difficult process. The positive feedback from ice covering the north is just too difficult to overcome and it takes several “warm” cycles to snap out of the glaciation. The oceans keep getting colder and colder, sucking CO2 out of the atmosphere until it drops below ~200ppm.
That’s when the magic happens. Vegetation starts dying off from CO2 starvation, even C4 grasses that evolved to handle our relatively low CO2 levels. This leads to dust storms, and the dust is deposited on the glaciers. Then the next time a warm cycle comes by, the lower albedo helps to melt the glaciers and we wind up in an interglacial, for ~10-15 kyr or so. However, the next cold cycle leads to a glacial period. I’m not sure owning an SUV will save you.
So watch out for reports that snow cover in N. Quebec doesn’t melt one summer. That’s the sign that things can go very bad, very quickly. Maybe we can prevent it, but it will take more than cars to do it.
Someone proposed a very interesting idea over at Judith Curry’s blog, which was that agriculture wasn’t practiced until CO2 levels recovered because plants wouldn’t be as productive.
I expanded on that thought a bit, noting that in the earliest agricultural societies, and for millennia thereafter, farming was barely break-even because the early farming populations could only support a small percentage of non-farmers, and could only do so reliably in the especially rich areas where civilization eventually took off, such as the Nile valley and Fertile Crescent.
If primitive farming at the higher, post-glaciation CO2 levels was barely above break-even, farming at lower CO2 levels likely wouldn’t pay off at all, so hunting and gathering would’ve been a better strategy.
The question it raises is whether we weren’t farming because we weren’t smart enough to farm, or whether we weren’t farming because we were smart enough not to, given the primitive tools and methods available, lower overall plant productivity, and paucity of crops that had been improved by generations of domestication.
“If primitive farming at the higher, post-glaciation CO2 levels was barely above break-even, farming at lower CO2 levels likely wouldn’t pay off at all, so hunting and gathering would’ve been a better strategy.”
It was several thousand years after the end of the last ice age ~11K ago before we started large scale agriculture in the fertile crescent. Once it took off the human population blew up; more people equals more fires set to clear land, cook food, general warmth/comfort etc. All of which would cause the CO2 levels to increase modestly over millennia or so of our doing so. Perhaps (maybe) forestalling the beginnings of the next inflection point to flip into another ice age; don’t how long it typically takes before a cold snap becomes full blown cascade to another ice age.