/sci/ - Science & Math

Ignoring AGW the earth has been in a stable oscillation between glacial and interglacial cycles. The regularity of the cycle is due to changes in the earths orbital properties over tens of thousands of years. Ignoring AGW we would slowly begin entering into the next glaciation in about 7 to 10 thousand years.

The data for the 10k years and those that preceded it does not exist. so your question is useless. Impossible to measure global temperatures prior to modern instrumentation.
Proxies and their interpretation are no different than reading tea-leaves.
Climate science is junk science.

>>10734067
>So why did this stabilise
there is a 100k year and a 400k year cycle
https://youtu.be/ztninkgZ0ws?t=10m

>>10734084
>>>/x/

>>10734084
Based if I can't fit it in my lab it's not real poster.

>>10734090
Cease with your projection.
Junk science and baseless speculation belongs in
>>>/x/
Tree ring, soil samples, and other means of divination are not reliable methods of taking temperature and are certainly NOT remotely tantamount to thermometers. The global presence of thermometers and temperatures recorded from them is a recent phenomenon, spanning the world over for little over a century, and most of the world two centuries, and a small portion of the world beyond that point. To compare the two samples as remotely similar is pure delusion.

>>10734095
>Imagine being this retarded

OP here, my next question would be whether there were analogous long, stable temperature phases at earlier times when humans were also around? My pet theory was that civilisation may have got started as soon as temperature stabilised. Temperature stabilisation would allow people to be in one place for a long time, where they could have continuous interaction with the same exact plants in a particular location. This would enable those plants to undergo the process of developing into a domesticated strain through continued interaction with humans.
But if there were analogous periods of stable temperature before 10,000 years ago then my theory is pretty much fucked, or at least needs additional qualifiers.

>>10734099
Terrific argument!

>>10734105
Well you haven't provided an argument, just
>ICE CORES AND TREE RINGS ARENT REAL BEACUSE I SAY THEY AREN'T!!!
So we can just laugh at you until you substantiate your claims

>>10734102
Here's the average temperature throughout all of human history and prehistory. Also domestication isn't dependant on temperature

>>10734067
That's not global temperature, it's Antarctic temperature from ice cores.

>>10734110
>implying tree ring samples are as accurate as a thermometer

>>10734114
Didn't modern humans arise at least 350,000 years ago?

>>10734114
Also my claim isn't that it's dependent on temperature (although, frankly, it does tend to kick off in places with the ideal temperature for humans [about 21 degrees C]). My claim is that it may be dependent on temperature STABILITY, since stable temperature would remove one thing that encourages people to move around, thus allowing humans to enter into a relationship with a particular line of plants, gradually altering their characteristics during this time until total domestication and the agricultural relationship emerging.
If one looks at the temperature record in the graph in OP, one sees a continuous high speed of temperature change, then a sudden shift to much slower temperature chance, just before civilisation kicks off. Coincidence? I would guess no.

So give it to me straight. Assuming the global temperature becomes highly unstable again, could agriculture still be maintained via people:
a) living underground as mole people farming fungi and feeding the fungi to animals for meat, or
b) by constructing greenhouses so the same crops could be planted repeatedly, or
c) by some other method?
Would rapid temperature fluctuation #cancel agriculture, and thus civilisation, or do we have the know-how to make it work?
Certainly got me thinking about the value that NASA has in terms of trying to make liveable hermetic environments.

>>10734126
>if they aren't as accurate they don't exist

>>10734270
>everything is equally accurate

>>10734194
Sure, and if you consider all of their existence "prehistory" then that graph is only all of history including every major civilization. Here's another one that includes all of prehistory

>>10734205
That's flawed reasoning

>>10734270
>not what was said anywhere
Only you've said this.
Excellent straw man. Thanks for proving yourself to be a retard yet again.

>>10734355
Can you explain how it's flawed?
I am seeing multiple phases of relative temperature consistency resembling our own right now, so perhaps that means my theory is wrong or at least needs more factors taken into account.
Does anyone here know why humans started civ when they did?

>>10734390
It's almost entirely based on assumptions and completely ignores other possibilities. There are other problems with it, but the biggest one is that you worked backwards and weren't very vigorous in doing so

>>10734292
That's the opposite of what I said

>>10734372
>not what was said anywhere
Oh just like >>10734126

>>10734402
Which assumptions and which other possibilities? How did I "work backwards"? How wasn't I "vigorous" (I guess you meant "rigorous")?

>>10734067
Bases on what?

>>10734450
I'm assuming you started with this idea and then tried to back it up with evidence which is considered poor practice because it's easy to get tunnel vision. It would be more vigorous to try to disprove your idea by finding other explanations that fit the observations and then reasoning which are impossible and which are more probable. Then you gather more data and do it again.

>Which assumptions?
>stable temperature would remove one thing that encourages people to move around
>allowing humans to enter into a relationship with a particular line of plants

>which other possibilities?
All of them

>>10734067
Ice core scientist from the other thread >>10725772 here

You should not believe anything presented by the World Economic Forum and bunch of economist. From first glance alone I can already tell that he's plotting Greenland water isotopes proxy and not global temperature. Protip: the way to know at first glance is to look at 12ka during Younger Dryas. If the temperature reverse, then it is a northen hemisphere proxy. If you look at pic related, southern hemisphere warms during the younger dryas.

>Based unstable global temperature that only stabilised about 10,000 years ago.
The glacial periods are characterized by abrupt T increase in greenland called D-O events named after Wili Daansgaard and Hans Oeschger, 2 pioneers of ice core research. For each given DO events there is an associated Antarctic Isotope Minima (AIM). This means that Greenland warms abruptly and Antarctica cools, and vice versa. The leading hypothesis to explain DO events is the bipolar seesaw https://www.nature.com/articles/4571093a.. Basically changes in deepwater formation forces redistribution of heat among Earth's hemispheres. As an ice core scientist, the guy on OP pic is dishonest in representing Greenland temperature as global temperature.

>So why did this stabilise and when is it going to go apeshit again?
DO events only happen in glacial period, not interstadial (warm) period. In glacial period there is less energy overall on earth because lower global temperature. Therefore small changes in ocean circulation can make relative big changes in local temperature (as shown in Greenland isotopes). During interglacial there is more energy to spread around, so everything is more stable. Temperature did not only stablilized 10k years ago. Marine isotope stage 5, Marine isotope stage 11, and Marine isotope stage 1e were also fairly long and warm interglacials.

>>10734532
So one might ask, how does global temperature looks like during glacial periods characterized by abrupt DO events?

The answer is nobody knew. Tree rings doesn't go beyond 15k, and there's not enough lake sediments or marine record proxies around to make coherent global temperature plot. Therefore, the only robust temperature reconstruction from the period comes from Greenland and Antarctica. We know that the poles are doing seesaws, one pole warms while the other cools. But we don't know how the seesaw effect affects global temperature.

>>10734540
Interesting. Thank you. Are there any ways to estimate the likely temperature of other parts of the world based on the temperature at the poles?

>>10735580
>Are there any ways to estimate the likely temperature of other parts of the world based on the temperature at the poles?

They are couple ways, but none of them ready for primetime science publication yet.

1. There's the classic compile all of your local proxies (lake sediments, marine records, terrestrial records). Essentially the shame thing that Shaun Marcott did >>10734114 and Michael Mann did 20 years ago when the 2000 yr hockey stick came out. However the data coverage is not great and the uncertainties would probably be high.

2. Another stretch would be assign correlation coefficients through empirical orthogonal function https://en.wikipedia.org/wiki/Empirical_orthogonal_functions and assign temperature of other regions based on how it correlates with present day Greenland and Antarctica. The problem is that the correlation that we found today might not be valid in the glacial period and even today there are many areas uncorrelated to both greenland and antarctic temperature.

3. One of the most interesting proxies developed for ice core is the Xe/Kr (xenon/krypton) noble gas ratio (https://www.nature.com/articles/nature25152).). Krypton, Xenon and Nitrogen are inert gases in the atmosphere. They only dissolve/outgass in/out of the ocean as proxy of temperature, and because they're well mixed, the amount of Kr/Xe in the atmosphere is a proxy for the whole mean ocean temperature. However, for some reasons we don't know there's a nagging difference that prevented this proxy from working as well as we thought. In theory all ice cores should show the same Xe/Kr ratio after all corrections and should converge to the same MOT (mean ocean temp). In practice it doesn't and it is an area of active research.

>>10734496
I started by noticing the temp stability coincided with the rise of civilisation. I then decided to see if my theory was false by looking for comparable periods of temperature stability in human history. Frankly, it seems like you got pissy that you posted a graph that wasn't super relevant to the discussion and now you're mad at me personally.

>>10736197
You are not completely wrong, agriculture was invented 23ky ago. https://www.sciencedaily.com/releases/2015/07/150722144709.htm and did not start to flourish until the Holocene at 12ka..

Agriculture did not exist during the previous interglacial, so it make sense that the first interglacial after agriculture was invented, civilization flourishes