Support the Arctic Sea Ice Forum and Blog

Author Topic: Credible source for a CO2 and Temperature graph over the past 100 million years?  (Read 377 times)

harpy

  • ASIF Lurker
  • Posts: 4
    • View Profile
I'm looking for a graph showing CO2 values and temperature values over the past 1 million + years.
I usually see just CO2 or JUST temperature.

1.  Is there a credible source of CO2 and temperature overlaid on the same graph (or just individual graphs for both temperature and CO2 with the same x axis) for the past 10+ million years or even just 500 thousand years anywhere?

2.  Is there a direct correlation between CO2 levels and global average temperature levels?


Pmt111500

  • ASIF Upper Class
  • Posts: 1124
    • View Profile
You could try to look for EPICA ice core measurements or other similar East Antarctic cores. The East Antarctic ice sheet has been there for the duration. Granted the lower layers get squished under several tons of pressure but similarities between cores allow making combinations of the records. They of course suffer somewhat of the limited geographical range. Else you might try to find Raymos foraminifera study of ocean sediments. The creatures have a specific temperature range in which they like to live before dying and dropping to ocean bottom and rather readily fossilize. Here the geographic range is not much of an issue, but rather the properties of water, which tend to lessen the fluctuations. If we accept the generally accepted theory of Meteorology that says the West Wind Drift isolates the Antarctic continent we may take the Antarctic T and [co2] to represent the southern hemisphere rather well (it would be a ~fixed amount off the hemispherical value.) Raymo and EPICA overlaps are supporting each other. This leaves the record of northern hemisphere for the period of 180000 - 1000000 years to be somewhat poorly attested, there aren't too many well preserved cores of sediment collected. Some have been obtained from north Atlantic, some from Siberia, the main trouble here is the sites shouldn't have had glaciers on them even during the severest glacials (ice ages in common parlance) as these very easily destroy or at least mix up the elder sediments. Then there's a whole bunch of science to be accepted to trust the methods scientists use to derive temperatures and CO2 levels.

Combining various sources of data to present a uniform graph you seem to be asking is not a task for any individual scientist, this might be seen as inappropriate tampering with data. I'd guess no one has gone through the trouble of going through 40 years of sedimentology and glaciology papers and data sources to produce exactly what you ask. But take this as a short introduction to an answer. There might be a direct pointer to what you ask, and I would also like to see the references in such a graph, I'd throw a guess of some 2000-3000 papers referenced.
« Last Edit: January 17, 2018, 06:06:30 AM by Pmt111500 »
A quantity relates to a quantum like camel's back relates to camel's _______ ? (back, vertebra, vertebral tendon, spinal disc, paralysis)

Pmt111500

  • ASIF Upper Class
  • Posts: 1124
    • View Profile
This might be of use too, https://skepticalscience.com/co2-lags-temperature.htm

The case is comparable to a situation in which both parties of a discussion are aggravating each other. It does not matter who (solar or greenhouse gas) started it. Things heat up and then they sulk to each other for the period of interglacial ;-) , or this time around, for the anthropogenic deglaciation.
A quantity relates to a quantum like camel's back relates to camel's _______ ? (back, vertebra, vertebral tendon, spinal disc, paralysis)

Pmt111500

  • ASIF Upper Class
  • Posts: 1124
    • View Profile
Oh, the question was also of the earlier millions of years. These distant times of over c.3.5 million years back and earlier, are not directly comparable to current values. This is because the ocean currents have changed so much. Currently there is no tropical connection between Pacific and Atlantic Oceans. The Middle America prevents the heat of El Nino to directly affect Northern Atlantic temperatures. Earlier still, the Drake Passage was formed in full scale some 30 million years ago, allowing the west wind drift to form. Prior that, very little of the worlds' oceans got so cold that they could form ice cover. (Writing these from memory, please correct if there are terrible mistakes and/or omissions of the generally accepted scientific assesements)
« Last Edit: January 17, 2018, 08:47:50 AM by Pmt111500 »
A quantity relates to a quantum like camel's back relates to camel's _______ ? (back, vertebra, vertebral tendon, spinal disc, paralysis)

Tor Bejnar

  • ASIF Upper Class
  • Posts: 1613
    • View Profile
Richard Alley's 2012 talk has some geological time temperature and CO2 graphs.  Look at minute 20 and 25, 31, 32, 35, 41 (and around those times, at least - I just skimmed this time).  The entire talk is worth watching!
Arctic ice is healthy for children and other living things.

Pmt111500

  • ASIF Upper Class
  • Posts: 1124
    • View Profile
Thanks Tor Bejnar for the link (recommended to people new to the subject at hand.)

As a sample of studies made of the way back times of Pliocene, I'll present a recent study of the effects of the closure of Central American Seaway: https://www.nature.com/articles/srep39842 , I admit the terminology is awful and newcomers to the subject won't get much from it. Many here though may find it interesting. I likely missed several points of it and didn't delve into it deeply, still found it express profound climatic changes tied to the event. It's a wonderous thing that genus Homo might thank this remote geological event for its existence!
A quantity relates to a quantum like camel's back relates to camel's _______ ? (back, vertebra, vertebral tendon, spinal disc, paralysis)

harpy

  • ASIF Lurker
  • Posts: 4
    • View Profile
How much of a lag is there between current atmospheric CO2 levels and the resulting increase in global average temperature?

Apparently, global average temperatures have not increased nearly as rapidly as CO2 levels have over the past 100+ years.

Looks like there should be an increase in global average temperature by something like 4-6 C compared to CO2 levels according to that climate skeptist graph.  Definitely more than 1C.

We're at 1.5+ C above baseline, right?

Thanks.

Human Habitat Index

  • NewMembers
  • ASIF Lurker
  • Posts: 1
    • View Profile
What is baseline ?

I'm astounded there is uncertainty about this.

Is it intentional obfuscation ?

Surely baseline is 1750.

Pmt111500

  • ASIF Upper Class
  • Posts: 1124
    • View Profile
How much of a lag is there between current atmospheric CO2 levels and the resulting increase in global average temperature?

Apparently, global average temperatures have not increased nearly as rapidly as CO2 levels have over the past 100+ years.

Looks like there should be an increase in global average temperature by something like 4-6 C compared to CO2 levels according to that climate skeptist graph.  Definitely more than 1C.

We're at 1.5+ C above baseline, right?

Thanks.

That is the question...of the 'test tube earth'. We have none to close to none (see 'Paleocene hyperthermals') records of such global warming events where the rise of co2 precedes warming. Not good ones, at least. Thus climate models. This question is a mess to solve. Much of climate science connects to this question,  as it is the one that gives rise to the threats to mankind. The 4 to 6 degrees rise of T the atmospheric levels of ghgs seem to indicate is delayed by the ice and oceans. By how much? We might check the speeds of ocean currents their heat capacity, how long does it take the atmospheric heat to reach specific levels in oceans? Add in ice on the planet you get questions people ask here, how stable are ice sheets to warm water intrusions, how much (and if) the clouds in summer delay the yearly melt in the arctic... This is not much of an answer.

We might seek the fastest local or areal changes seen in records. These, for sure, have happened. Thus we get headlines of western (and central) American megadroughts or speedy restructurations of ocean currents in North Atlantic, there are many such events in areal records. These somewhat tie to the studies of 'stuck weather' several top scientists are nowadays pursuing. I, for one, am not surprised anymore if I hear of a heat wave of over some 2-3 degrees above previous records, that is what the atmosphere would be giving us, if the oceans (and remaining ice) would not warm up so slowly. Areal changes in climte system may change very rapidly geologically speaking, the system could enter 'permanent (or was it mega-) el nino' imho at anytime. The same goes for currents in North Atlantic giving rise to some 'alarmist' calls here in the forum of imminent 'Blue Ocean Event' after which it is assumed that most of the North Atlantic would soon warm up. This imho takes at least 10 years, but the catch 22 here is there would be no going back to ice gerönerating condition (potential searches 'hysteresis in climate system', 'irreversible climate change' ?). A large rise in T belittleling the size of medieval warming period would ensue, according some. More conservative estimates (style ipcc) are plentiful in the forum (40-50 years), some still hope the meltwater off of Greenland Ice Sheet provides a buffer against this for longer period ('stopping of the Gulf stream (and the whole north atlantic gyre)). I don't see this last one happening.

I don't remember if the Alley lecrure included an estimate of this.  The simplest way to look at this question, we might take the 1,5 degrees pretty close realised (-aerosols) nowadays and look for the time when the co2 was on equivalent level... Here too we have a bit of complications due the 'early anthropocene hypothesis' and due the earliest temperature measurements ('18th to 19th century temperature records). Without going to detail, the resulting answer to the question of delay doesn't change much, but this is again speaking climatologically, so the exact answer may vary by a decade or even two.

Still not much of an answer, if one is after a specific number of years, but some might throw in an exact number in discussions if they've calculated one recently. Not much more I remember straight away wrt Big Question without going through some notes snd papers so 'PMTs crash course on Paleoclimate' stops here. And mind you, I'm not a practising scientist, though have studied some climate stuff. All the errors in the above are my owm and as before, please correct if the text is dramaticlly off the regular scientific thoughts.

« Last Edit: January 19, 2018, 09:40:12 AM by Pmt111500 »
A quantity relates to a quantum like camel's back relates to camel's _______ ? (back, vertebra, vertebral tendon, spinal disc, paralysis)

crandles

  • ASIF Upper Class
  • Posts: 1829
    • View Profile
How much of a lag is there between current atmospheric CO2 levels and the resulting increase in global average temperature?

Apparently, global average temperatures have not increased nearly as rapidly as CO2 levels have over the past 100+ years.

Looks like there should be an increase in global average temperature by something like 4-6 C compared to CO2 levels according to that climate skeptist graph.  Definitely more than 1C.

We're at 1.5+ C above baseline, right?

Thanks.

I think you might be making mistake along following lines: (I am converting to last 800,000 years rather than 1 million + because we have better data  from ice cores.)



could suggest up to 15C change from CO2 change of 185 to 280 (.6 of a doubling) which could suggest a long term earth system climate sensitivity of 15/.6=25C.

This just isn't right:
Firstly, those are EPICA dome C temperatures so local temperatures at high latitude not global average temperatures and we would suspect high latitude temperatures vary more by a factor of 2.

Secondly, there was much more ice extent in glacial periods meaning much more albedo feedback so this is another factor 2 effect. See http://onlinelibrary.wiley.com/doi/10.1002/2017PA003190/full

So I think we can divide that 25 by at least 4 to get climate sensitivity of 6ish. But it would be foolish to use this crude analysis of climate sensitivity of 6 only when there are other better lines of evidence that suggest nearer 3C.

We have had just over half a doubling.
Giss Loti 2017 (non Nino or Nina year) 1.15C above preindustial
so 0.5C of committed warming re oceans take a long time to warm up would make this add up for 3C sensitivity.

Of course a longer term earth system sensitivity could well be 6C but ice sheets take a very long time to change their area significantly and they are much smaller now than in past. So yes, you can get to a couple more C to come, but it will take a long time to arrive and who knows what we will be capable of doing by then.