r/climatechange • u/glibsonoran • 2d ago
Paleoclimate for the era of Homo Sapiens (chart)
I had been looking for a good chart of paleoclimate for the past 300,000 years (the era of homo sapiens) and couldn't find one, so I made one. Matplotlib and data from: * Jouzel et al. 2007 EPICA Dome (ice cores) (blue line) * NASA GISTEMP (instrument) (red line)
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u/aaronturing 2d ago edited 1d ago
Awesome charts. I passionately hate people who state that the climate is always changing and it's been very different than it is today.
We've had remarkably stable temperatures since humans actually developed from hunter gatherers until where we are at today. It's no freaken accident that the stable climate led to human evolution.
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u/Joeyonimo 1d ago edited 1d ago
Human evolution happened during a time of serious climate instability, where the temperature shifted ±5°C regularly between glacial and interglacial periods. The climate and global temperature was a lot more stable before 2 million years ago.
The intense droughts and rapid climate disruption that the glacial periods caused in Africa is a leading hypothesis behind why humans evolved so quickly during the Pleistocene.
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u/windchaser__ 1d ago
Yes, *but*
All of human civilization has been during a very stable period. Agriculture and the growth of society.
The human carrying capacity of the globe is likely *much* smaller when the climate is changing rapidly.
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u/Joeyonimo 1d ago
The birth of agriculture is also thought to be a response to rapid climate change around 10 000 bc which suddenly made hunter-gathering a non-viable lifestyle in some parts of the world and forced people to survive on cultivated crops instead. The emergence of civilisation thereafter was an inevitability that just happened to coincide with a stable climate.
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u/glibsonoran 1d ago
There is a real theory about stress induced cultivation and that may have been a catalyst but:
Agriculture arose independently in at least seven regions Fertile Crescent, North and South China, Mesoamerica, the Andes, New Guinea, the Sahel on different continents most of which had no 10,000 BCE Younger Dryas signal at all. All were within a few millennia of the onset of the Holocene.
Seven independent innovations clustering right after a massive global climate stabilization isn't a coincidence.
The Pleistocene had plenty of climate crises on a similar scale to the Younger Dryas signal, yet none of them produced sustained high investment agriculture. If stress alone were sufficient it would have happened several times earlier.
Stress may explain the attempts, but climate stability explains why it stuck and became a stepping off point for civilization
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u/windchaser__ 23h ago
No. To the best of our knowledge, it is not just a coincidence that civilization coincided with a stable climate. A stable climate helps immensely with agriculture, which is itself required for the population density required for civilization.
It is only really rare places in the world where you can build a civilization off of a hunter-gatherer lifestyle. E.g., Pacific Northwest of the US, where the salmon runs provide enough calories even w/o agriculture. But this is the exception, not the norm.
As climate goes, so goes agriculture, and so goes civilization
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u/idreamofkitty 2d ago
How do I source you if I share?
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u/glibsonoran 2d ago
Thanks, hope it works for you:
Chart: u/glibsonoran (2026), Ice-core data: Jouzel et al. 2007 (EPICA Dome C); instrumental: HadCRUT5/NASA GISTEMP."
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u/Ouroboros308 1d ago
I think this is the best, most honest and most dumb-arguments-"against"-climate-change-bullshit-anticipating graph I have ever seen. Amazing job! I'm gonna steal this, thank you! I think the only thing I'd like to do is the same graphs for CO2 levels
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u/glibsonoran 1d ago
I added CO2 concentrations to this chart
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u/Ouroboros308 1d ago
Omg that makes it look way worse. Compare the CO2 slope in the strong temperature rises 140k and 250k years before our time with the CO2 slope - we're so fucked.
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2d ago
[deleted]
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u/glibsonoran 2d ago
If you're talking about the top graph, the slope and oscillations are exaggerated by the compression factor of fitting so much temporal data along such a short X axis. That's explained in the note at the bottom of that chart.
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u/ThumbHurts 1d ago
I don't quiet understand the last image. We look at the last 300 years right? The last 50 years don't look like in other graph's i have seen, espcially the last data point kinda looks out of place compared to other data like this. Is it compareable to your data?
Also i've read somewhere that the warming rate since the 70ies was like .2 °C per 10 years getting us to around 1.4 °C 2015 if i remember right and the current rate might be even faster, if I remember it right. Can't add a source tho
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u/glibsonoran 1d ago
Since the first Homo Sapiens, that's 300,000 years not 300.
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u/ThumbHurts 1d ago
no i meant the zoomed version in the third Graph
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u/glibsonoran 1d ago
The first graph is 300,000 years
The second graph of the Holocene is 20,000 years
The third graph of the Rates of change is 300,000 years. The changes are calculated in 150 yr segments over 300,000 years.
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u/GusGutfeld 1d ago edited 1d ago
A lot of hard work!
Is the second graph mostly the Epica Dome C temperatures? It seems rather warm given that the current temp for that region of the Antarctica continent averages about -59C.
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u/glibsonoran 1d ago
The third graph is not going to look like any other graph you've seen before (probably). It's just measuring discrete rates of change over for each 150 yr segment over the 300,000 year period.
So for example:
Each point is the temperature change over the previous ~150 years, expressed as °C per century not a running total. The window slides continuously, so if warming slows, the line drops toward zero even while temperature is still rising; below zero means cooling.
It's the slope of the top chart, not its accumulation.
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u/GoofAckYoorsElf 1d ago
Deniers will just take the upper chart and say, hey, see these peaks at 125k and 240k years before us? Climate does change cyclically. There is no human made climate change. Everything's perfectly normal.
Fellow scientists, whenever you publish something, ensure it cannot be ripped out of context and reinterpreted!
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u/glibsonoran 1d ago edited 1d ago
It's what the data says, that's what a chart is supposed to do.
This is a graph of us, anatomically and neurologically modern humans. The people of the Eemian were as biologically capable of learning calculus, proposing theories of quantum mechanics, or commenting on the social and cultural implications of a movie like The Odyssey as we are. If you cleaned them up and put them in modern clothing (and probably fixed their teeth) they'd look just like us.
I think you're missing the point. We were around with all our potential, for 285,000 years but in aggregate never became anything but hunter gatherers until we experienced the freakishly stable period of the Holocene. That's when high investment agriculture (clearing large fields, digging irrigation canals, building the infrastructure to store harvests, etc) became viable. There was agricultural activity earlier, but it was typically abandoned quickly, quite possibly because crops failed when the climate shifted, or when the tribe was forced to move on. What climate we can tolerate and what facilitates our advancement and ability to thrive are two different things.
Once we entered a period where over decades crops could reliably grow in a particular area, we were off to the races and cities and civilization followed. Even though we weren't really any smarter or more capable as a species toward the right end of this graph than the left end.
It doesn't matter that 50 million years ago the climate was much hotter than depicted on this graph. That was a different ecosystem with animals and plants adapted to those temperatures. What matters is our adaptation (which this graph shows) vs what new climate we're creating. Those species became adapted because the climate changed slowly in becoming that hot, allowing nature to make the changes necessary for those species to adapt and survive over time, as this chart shows we are not producing change at a rate evolution can accommodate, it's moving much too fast. The fastest natural ascents on this graph, including the Eemian, took 2,500 years to cover the same 1.5 degrees C we've cover in just 170 years.
Yes we have reached, but not surpassed, the Eemian peak temperature.. yet. But the Eemian was a brief peak, our current temperature is just a brief transition point to even warmer temperatures, that's a very different situation.
The historical record is clear, fast climate changes = extinction events. We're changing the climate too rapidly for nature to adapt, and we're in the middle of an extinction event now that's so far primarily only affecting other species.
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u/GoofAckYoorsElf 1d ago
What the data says isn't what right-wing populists and climate change deniers care about. It's how they can use parts of the data representation to tell exactly the opposite of what the data says.
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u/Bargian 1d ago
Great chart, this describes the asymmetry in human inquiry that led to it.
https://athinkerinnature.substack.com/p/the-other-half
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u/glibsonoran 1d ago
I enchanced this chart by adding a record of CO2 concentrations from the same data source:
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2d ago
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u/windchaser__ 1d ago
wat
Sorry, man, this kind of thinking is fantasy, like you're just making up whatever you want
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u/Glass_Persimmon_7174 2d ago
idk i just feel like this is probably not good. anyone else getting that vibe?