Reader “Markx” writes in Tips and Notes on a paper I hadn’t noticed before (because it was published before WUWT was born). Of course it only works if CO2 has a long residence time and/or our elevated emission levels continue. We need at least 3x more CO2 to pull off the delay.
A movable trigger: Fossil fuel CO2 and the onset of the next glaciation. David Archer and Andrey Ganopolski
Published in G3 Geochemistry Geophysics Geosystems Research Letter Volume 6, Number5 5 May 2005
Abstract:
The initiation of northern hemisphere ice sheets in the last 800 kyr appears to be closely controlled by minima in summer insolation forcing at 65N. Beginning from an initial typical interglacial pCO2 of 280 ppm, the CLIMBER-2 model initiates an ice sheet in the Northern Hemisphere when insolation drops 0.7 s (standard deviation) or 15 W/m2 below the mean. This same value is required to explain the history of climate using an orbitally driven conceptual model based on insolation and ice volume thresholds (Paillard, 1998). When the initial baseline pCO2 is raised in CLIMBER-2, a deeper minimum in summertime insolation is required to nucleate an ice sheet. Carbon cycle models indicate that 25% of CO2 from fossil fuel combustion will remain in the atmosphere for thousands of years, and 7% will remain beyond one hundred thousand years (Archer, 2005). We predict that a carbon release from fossil fuels or methane hydrate deposits of 5000 Gton C could prevent glaciation for the next 500,000 years, until after not one but two 400 kyr cycle eccentricity minima. The duration and intensity of the projected interglacial period are longer than have been seen in the last 2.6 million years.
Some excerpts:
“Models require some amplifying feedback, from sea ice … or the terrestrial biosphere ….to nucleate on the basis of insolation forcing, but insolation is always the primary driver.”
and
An anthropogenic release of 300 Gton C (as we have already done) has a relatively small impact on future climate evolution, postponing the next glacial termination 140 kyr from now by one precession cycle.
Release of 1000 Gton C … is enough to decisively prevent glaciation in the next few thousand years, and given the long atmospheric lifetime of CO2, to prevent glaciation until 130 kyr from now.
If the anthropogenic carbon release is 5000 Gton or more….[…]… The model predicts the end of the glacial cycles, with stability of the interglacial for at least the next half million years…
Figure 3. Effect of fossil fuel CO2 on the future evolution of climate. Green represents natural evolution, blue represents the results of anthropogenic release of 300 Gton C, orange is 1000 Gton C, and red is 5000 Gton C. (a) Past and future pCO2 of the atmosphere. Past history is from the Vostok ice core [Petit et al., 1999], and future anthropogenic perturbations are from a carbon cycle model [Archer, 2005]. (b) June insolation at 65N latitude, normalized and expressed in s units. 1 s equals about 20 W m2. Green, blue, orange, and red lines are values of the critical insolation i0 that triggers glacial inception. The i0 values are capped at 3 s to avoid extrapolating beyond model results in Figure 3; in practice, this affects only the 5000 Gton C scenario for about 15 kyr. (c) Interglacial periods of the model. (d) Global mean temperature estimates.
Not having mile thick ice sheets crush northern hemisphere cities is a good thing, don’t you think?
Full PDF here: http://geosci.uchicago.edu/~archer/reprints/archer.2005.trigger.pdf
The term pCO2 is more commonly used as the partial pressure of CO2 in a gas or liquid, and its units are pressure units, eg mm Hg.
Hansen shouts ‘Neanderthal’!
Not having mile thick ice sheets crush northern hemisphere cities is a good thing, don’t you think?
Depends on the city. Some festering pits of pestilence are best covered over and left to decompose for a very long time, like with landfills, you know? 😉
I am looking forward to the next ice age, as it will wipe out all the idiotic progressives. While I too will suffer the same fate, I recall Kennedy’s sage advice: “ask not what your country can do for you…”
This, of course, was Bert Bolin’s original hypothesis way back in 1959 when he was an obscure scientist. Then it was good news when interviewed for a BBC program “The Weather Machine”. Later he saw all the money and influence he could get (and did get) by pretending it was bad news.
Uh huh, its another paper that missed April 1.
I think the have the sign inverted,man caused co2 actually causes cooling, the last 15years provide IPCC certainty and we must cut emissions or we will all freeze here after.
Jimbo says:
April 27, 2013 at 1:03 pm
” John says:
April 27, 2013 at 8:54 am
…………..
“But the earth is nevertheless warmed by CO2…It stands to reason that the “right” amount of CO2, at the right time, could keep us out of another ice age….”
Oh really! Click here and look at the later half of the Cretaceous and start of the Tertiary.”
Jimbo, from your link I note that the global temp curve maxes out at ~25C. This is rather high in terms of global T even though it is still below Willis’s Thermostat Limit of 30 for the ocean temp. Also, although there is a very general correlation with the widest swings in CO2 levels, levels between 1000-7000ppm appear to support this 25 C suggesting not a strong correlation.
Here is a nice zoom-in of the Milankovitch Cycles (mid-June solar insolation at 65N) from David Archibald (derived from Loutre and Berger, 2000).
http://wattsupwiththat.files.wordpress.com/2009/02/insolation-at-65-north.jpg
Generally, in looking back at all the ice ages in the last 1.0 million years (which is when the length of the ice ages switched to about 100,000 years), it appears to me that this value needs to drop below about 470-465 W/m2 to kick us into an ice age. After that initial drop, a lot of ice volume builds up and it takes two or three good up-swings to break the back of glaciers to put us back into an interglacial (essentially Gerald Roe’s ice volume model which is really the only explanation that seems to work ).
The June solar insolation forecast for 65N is that we are not going to get into that 465 W/m2 range until 55,000 years from now (or more likely 125,000 years from now).
It really comes down to, is the summer sun warm enough to melt all the winter snow at lower altitudes (and melt some of the Arctic sea ice in September) at 75N (which is a more accurate latitude than 65N. 75N is where all the action is.
If the snow and ice melts at 75N in the summer, there is no ice age and no glaciers build up on Ellesmere Island, Baffin island and northern Greenland kicking us into an ice-Albedo feedback loop that puts glaciers in Chicago.
Over the next 2,000 years, solar insolation at 65N declines by about 0.5 W/m2 (a tiny, tiny amount) and the Arctic sea ice and the snow on Ellesmere Island will continue melting in the summer.
We’re stuck in the interglacial which will likely be the longest one since the ice ages started 2.6 million years ago. The Milankovitch Cycles are not as regular as many people believe.
http://wattsupwiththat.com/2009/02/23/ice-ages-and-sea-level/
From Sean on April 27, 2013 at 2:12 pm:
Nah. As always happens with these infestations, there’s an elite class of smart “progressives” who are in control of the lesser ones, positioned to take advantage regardless. The idiotic progressives are like worker bees, generated by the queen bees as needed, although new queens can be “adopted” by and take over other worker bees like after an old queen dies or has a sex scandal with the wrong species. The “idiotic” group lives and dies for the benefit of the hive, while not realizing the hive exists for the benefit of the queen, who would be nothing without it.
The smart ones are rich enough to migrate where needed, towards poles or equator. They’ll make more idiotic progressives when they get there.
Wow, you’re expecting a really long life.
That was superseded by the Obama Indoctrine: Ask not what your country is doing to you, ask how you can let your country do you even more.
Mitchell @9:27:
Nicc calc. 64% “missing”? Consider this: never was produced. A negative Trenberth Event. All eco-green activist use top-end estimates, all governments exaggerate industrial activity for ego and green policies and future claims of reduction. Compounding error:eco.green then say government lies to prevent need for action, say situation worse than stated. Trouble is, observations then show Earth more resilient than modeled, mitigation without regulation sufficient.
Initial exaggeration drives scare, later refutes models. Like the BP Gulf Coast oil spill. I say way less oil spilled than claimed, reason couldn’t find oil plume or mess on seafloor later. But high volume resource estimates benefit company, environ-activsts and government. Also competitors who want oil leases on-trend.
ALL climate change data that is a calculation and not a direct measurement should be viewed suspiciously. Ask, who benefits from the benefit-of-doubt going one way or the other.
Graph CO2 global production per year vs CO2 ppm.
Ain’t that interesting: bio-processes, ocean absorption or exaggerated data?
“The Carboniferous Period and the Ordovician Period were the only geological periods during the Paleozoic Era when global temperatures were as low as they are today. To the consternation of global warming proponents, the Late Ordovician Period was also an Ice Age while at the same time CO2 concentrations then were nearly 12 times higher than today– 4400 ppm. According to greenhouse theory, Earth should have been exceedingly hot. Instead, global temperatures were no warmer than today. Clearly, other factors besides atmospheric carbon influence earth temperatures and global warming.”
http://www.geocraft.com/WVFossils/Carboniferous_climate.html
Indeed – politics and climate models?
Bill Illis says:
April 27, 2013 at 3:21 pm
Tzedakis appears to believe that Milankovitch orbital phase takes precedence over insolation magnitude. Note the text in bold in the abstract below.
Thus it may be within 1500 years, not 55,000 years, that glacial inception occurs.
Determining the natural length of the current interglacial
P. C. Tzedakis, J. E. T. Channell, D. A. Hodell, H. F. Kleiven & L. C. Skinner
Nature Geoscience (2012) doi:10.1038/ngeo1358
Received 23 May 2011 Accepted 28 November 2011 Published online 09 January 2012 Corrected online 10 January 2012, corrected by WUWT 28 April 2013.
The current orbital configuration is characterized by a weak minimum in summer insolation. However, the timing of the hypothetical next glaciation remain unclear. Past interglacials can be used to draw analogies with the present, provided their duration is known. Here we propose that the minimum age of a glacial inception is constrained by the onset of bipolar-seesaw climate variability, which requires ice-sheets large enough to produce iceberg discharges that disrupt the ocean circulation. We identify the bipolar seesaw in ice-core and North Atlantic marine records by the appearance of a distinct phasing of interhemispheric climate and hydrographic changes and ice-rafted debris. The glacial inception during Marine Isotope sub-Stage 19c, a close analogue for the present interglacial, occurred near the summer insolation minimum, suggesting that the interglacial was not prolonged by subdued radiative forcing. Assuming that ice growth mainly responds to insolation, this analogy suggests that the end of the current interglacial will occur within the next 1500 years.
[Note – some irrelevant discussion on trace gasses was removed from the text to clarify the text.]
To everyone on this site who thinks that CO2 has zero or almost no effect on warming the planet — riddle me this:
Why is it that people like Patrick Michaels get such cheers (as they should) when they do the science better and find out that the actual CO2 sensitivity is about 2 degrees C for a doubling of CO2, using actual temperature records in many of those studies? What is good about this is that the IPCC mean temperature increase for a doubling of CO2 is about 80% too high, and a crisis isn’t nigh. In other words, the IPCC is part of trying to panic people into thinking that if we don’t completely stop emitting CO2, right now, all sorts of bad things will happen. Thanks to Michaels and others, almost all of them featured on WUWT at some time (e.g., Schmittner et al), we now have good evidence that the IPCC, like Michael Mann, has been playing games (in fact, Mann hid the decline while a lead author for the IPCC).
But the message is also that CO2 does in fact cause warming, about 2 degrees C, more or less, from a doubling.
And no, I didn’t forget that water vapor is a powerful greenhouse gas.
The issue is what happens when you double CO2, INCLUDING reducing the high feedbacks that the IPCC assumed from water vapor. That answer, according to Michaels and the several new studies he cites, is about 2 degrees C, plus or minus:
http://wattsupwiththat.com/2013/04/25/a-compilation-of-lower-climate-sensitivities-plus-a-new-one/
Skeptics: they look at reality, at what temperatures have done the last 15 years, and say the IPCC and Michael Mann are feeding us BS, and that doubling of CO2 won’t get nearly the increase in temperatures that are claimed by the IPCC and Mann.
Deniers: they ignore the huge amount of science that says that, yes, CO2 does increase temperature, and say that doubling CO2 in the atmosphere won’t affect temperatures, or will do so hardly at all.
I’m on the side of the scientific skeptics, like Michaels. Just because Mann and the IPCC feed us BS doesn’t mean that we can believe whatever we want — we still must be true to what the science actually says, when the process works out and we get more reliable answers. And then the policies that follow must be based on the new, better science, not what the IPCC and their PR teams want us to do.
phlogiston says:
April 27, 2013 at 4:01 pm
—————
I’m not sure how they were calculating a bi-polar see-saw, but they did use Lisiecki and Raymo (2005) to come up with this. The authors improved on the dating from their 2005 paper with (LR 2009) for the north Atlantic and north Pacific.
This might be the first time this is shown but the correlation between Antarctica and the north Atlantic over the last 800,000 years is scary close. They are both moving almost exactly the same.
http://s14.postimg.org/gqap88co1/Last_800_K_NAtl_Antarctica_Temps.png
shepherdfj is correct. It is the Isthmus of Panama that is the cause of the Pleistocene era, and only its removal, allowing warmer waters from the Pacific to mix with the Atlantic, will prevent this from recurring again and again.
Only the action above, and halting Impactors from causing immediate sudden drops in temperature, will allow the planet to go back to a more stable climate scenario.
shepherdfj is correct. It is the Isthmus of Panama that is the cause of the Pleistocene era, and only its removal, allowing warmer waters from the Pacific to mix with the Atlantic, will prevent this from recurring again and again.
Only the action above, and halting Impactors from causing immediate sudden drops in temperature, will allow the planet to go back to a more stable climate scenario.
Those carbon cycle models couldn’t predict their way out of a brown paper bag.
What is readily apparent from this post and many of the comments that follow is that we are nowhere near understanding what triggers glacials and interglacials. What is more, we are unlikely to achieve a full understanding for millenia, if ever. While the summer insolation at 65N may be the current favourite explanation, it can neither be proved or disproved, just like all the other theories expounded or linked to in comments.
“Not having mile thick ice sheets crush northern hemisphere cities is a good thing, don’t you think?”
The mile-thick ice sheets are part of the natural rhythm of life. Why do you hate the Earth so much?
It is the Isthmus of Panama that is the cause of the Pleistocene era
=================================================
One tries to be tolerant, but this is just plain ignorant. Puleeese, check out the reconstructions of Scotese or Blakely. Even at the PETM, about 48 million years before the Pleistocene, there was a very significant island arc and continental shelves blocking the Isthmus on Panama. the most that can be imagined even then is an “Atlantic Warm Pool” at the restriction.
It is crystal clear from continental reconstructions that Ice Ages, meaning extended periods with multiple glacial/interglacial cycles, are not about continental drift. There have only been a few of them in the last 600 million years and they have occurred in a wide variety of continental configurations, none of them, except the current, like today.
Jimbo, I didn’t say that we will have any problem in 100 or 200 or 300 years. Quite on the contrary. I agree with your comment – and with Crichton’s comments on manure in New York – as much as you do. But I said that the fossil fuels won’t be our main source of energy because of a combination of the natural (not requiring any subsidies!) research of the alternatives and the increasing price of the fossil fuels whose easily accessible volume is limited (the limit depends on how we define “easily”) and that will require more complicated technologies to be obtained – not just fracking which may be OK for 150 years.
Not bad trick for a trace gas. So it really is responsible for global not-cooling – a very normal cyclic event – at the same time it is responsible for global warming – another expected event following a cold period. The alarmists are right – we’re going to be warm (and comfortable though they don’t make this claim) for centuries. Meanwhile I’m still wearing a wool shirt every day outside because it is freezing cold. I’m going to go light my burn barrel and hustle this warming along.
John:
Nice try at damage limitation in your post at April 27, 2013 at 4:51 pm.
But it is a total fail.
Climate sensitivity is so low that any effect of increased CO2 will be much too small for it to be detectable because natural climate variability is much, much greater.
Empirical measurements (n.b. NOT model-derived estimates) show climate sensitivity is much lower than you claim (i.e.you claim 2°C for a doubling of the air’s CO2 content).
Climate sensitivity is only ~0.4°C for a doubling of the air’s CO2 content equivalent.
This is indicated by the independent studies of
Idso from surface measurements
http://www.warwickhughes.com/papers/Idso_CR_1998.pdf
and Lindzen & Choi from ERBE satelite data
http://www.drroyspencer.com/Lindzen-and-Choi-GRL-2009.pdf
and Gregory from balloon radiosonde data
http://www.friendsofscience.org/assets/documents/OLR&NGF_June2011.pdf
Richard
Total rubbish. Present atmospheric CO2 levels are not high but low compared to the past. No amount of CO2 will prevent an ice age—- 8000ppmv did not prevent a severe ice age during the Ordovicean.
Emitting an enormous slug of CO2 is the least efficient and most damaging way to prevent the next glaciation.