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
Conclusions
We need to achieve major warming to prevent the catastrophe of another glaciation in about 1500 years.
We need validated models with an accurate climate sensitivity to reliably predict the onset of the next glaciation and the impact of measures to avoid it.
And a good dose of humor such as provided by Minnesotans for Global Warming
Richard says
http://wattsupwiththat.com/2013/04/27/good-news-elevated-co2-may-extend-interglacial-prevent-next-ice-age/#comment-1289646
henry says
clearly you have not been paying any attention at all to the remarks by various commenters here
don’t worry, we do not consider you a fool,
just one of the more ill-informed
If Humanity can Geo-engineer so readily, Why not turn Mars into Hawaii.
The hubris, it burns.
No, it will not.
CO2 is not a climate driver.
Is there a bit of schizophrenia among some readers at WUWT? Some seem to think that CO2 has NO warming influence, or too little to matter. Yes just a few posts ago, the scientist and skeptic Patrick Michaels reviewed a number of papers, including his own perspicacious 2002 study, which found that the climate sensitivity to CO2 is lower than forecast by models. Wonderful news, and for those of us who use data instead of model results to develop our opinions, expected news.
But the earth is nevertheless warmed by CO2 (and black carbon, and methane, and tropospheric ozone, and cooled by sulfate from humans and from volcanos). It stands to reason that the “right” amount of CO2, at the right time, could keep us out of another ice age, given that CO2 lasts in the atmosphere for over a hundred years, once emitted. Make no mistake, based on the previous several interglacials, we are (or should be) headed down into another ice age.
So the science question is, what is the “right” rate of emissions, not too cold, not too hot? When we get the models right, IF we ver get the models right, we will probably conclude that we want to slow down our CO2 emissions in this century (not come to a grinding and economically damaging halt), so that we will have CO2 to emit in the right quantities in future millennia. Obviously, this is a guesstimate. Don’t shoot me.
Readers of WUWT should know that this is not the first paper to find that CO2 emissions from humans have kept the world warmer. William Ruddiman at U VA published a paper in 2003 saying that the deforestation of temperate areas where farming began, as humans cleared more land to grow crops, has very slowly made the earth warmer for 6000 years (the CO2 from decayed or burnt trees goes to the atmosphere, the crops don’t take up as much CO2 as the trees had stored).
Here is a link for Ruddiman:
http://en.wikipedia.org/wiki/William_Ruddiman
Here is a link to his most well known paper (see Figs. 5, 6, and 9 especially, but the whole paper is worth your time):
http://stephenschneider.stanford.edu/Publications/PDF_Papers/Ruddiman2003.pdf
it seems many of you still do not get it
we are already cooling for the past 11 years (= one whole Schwabe solar cycle)
http://www.woodfortrees.org/plot/hadcrut4gl/from:2002/to:2013/plot/hadcrut4gl/from:2002/to:2013/trend/plot/hadcrut3vgl/from:2002/to:2013/plot/hadcrut3vgl/from:2002/to:2013/trend/plot/rss/from:2002/to:2013/plot/rss/from:2002/to:2013/trend/plot/gistemp/from:2002/to:2013/plot/gistemp/from:2002/to:2013/trend/plot/hadsst2gl/from:2002/to:2013/plot/hadsst2gl/from:2002/to:2013/trend
it will not get better
it will only get worse
http://blogs.24.com/henryp/2012/10/02/best-sine-wave-fit-for-the-drop-in-global-maximum-temperatures/
John says
But the earth is nevertheless warmed by CO2
henry says
who knows for sure? I don’t think it was properly tested? why would the net effect not be cooling rather than warming?
http://blogs.24.com/henryp/2011/08/11/the-greenhouse-effect-and-the-principle-of-re-radiation-11-aug-2011/
The effect CO2 as a Greenhouse gas becomes ever more marginal with greater concentration
The political target of limiting the effect of Man-made global warming to only +2⁰C can never be attained. According to well understood physical parameters, the effectiveness of CO2 as a greenhouse gas diminishes logarithmically with increasing concentration and from the current level of ~390 ppmv, (parts per million by volume). Accordingly only ~5% of the effectiveness of CO2 as a greenhouse gas remains beyond the current level.
This inconvenient fact is well understood in the climate science community. It can be accurately modeled using the Modtran program. The logarithmic diminution of the effect of CO2 is probably the reason why there was no runaway greenhouse warming from CO2 in earlier eons when CO2 levels were known to be at levels of several thousands ppmv.
Remarkably, IPCC Published reports , (TAR3), do actually acknowledge that the effective temperature increase caused by growing concentrations of CO2 in the atmosphere radically diminishes with increasing concentrations. This information is in their report. It is well disguised for any lay reader, (Chapter 6. Radiative Forcing of Climate Change: section 6.3.4 Total Well-Mixed Greenhouse Gas Forcing Estimate).
The diminishing percentage effectiveness of CO2 as a greenhouse gas as acknowledged by the IPCC and its concomitant diminishing temperature effect are as follows:
increment cumulative
0-100 ppmv: according to David Archibald / Modtran data ~2.22°C ~2.22°C
100-200 ppmv: plants die below this level of CO2 +~0.29°C ~2.51°C
200-300 ppmv: noted as the preindustrial CO2 level +~0.14°C ~2.65°C
300-400 ppmv: current level IPCC attributes all as Man-made +~0.06°C ~2.71°C
400-600 ppmv: business as usual till 2100 +~0.08°C ~2.79°C
600-1000 ppmv: improving levels for plant growth +~0.06°C ~2.90°C
Accounting for the diminution effect the actual temperature reductions achievable, the calculated values are in the range of few hundredths to a few thousandths of a degree Centigrade. As the margin of error for temperature measurements is about 1.0°C, these miniscule levels the temperature effects for all the efforts of those nations attempting to control their CO2 emissions, (only about 12% of world CO2 emissions), are marginal, immeasurable and thus irrelevant.
Although the IPCC tacitly acknowledges that this crucial diminution effect with increasing concentrations effect exists, it certainly does not go out of its way to emphasise it. Like the Medieval Warm Period, that they attempted to eliminate with the Hockey Stick graph in 2001, the panel knows that wide public knowledge of the diminution effect with increasing CO2 concentration would be utterly detrimental to their primary message.
“Man-made CO2 emissions are the cause of climate change”.
The IPCC certainly does not explain these devastating consequences for the CAGW theory in their Summary for Policy Makers. This is because the IPCC is an essentially political organisation, that is solely tasked with the promotion and presentation of Man-made Climate Change from CO2 emissions, as an accepted and non-contentious fact for world’s politicians.
Thus the IPCC is entirely misleading in its central claim for Policy Makers, as they say:
“Warming of the climate system is unequivocal. Most of the observed increase in global average temperatures since the mid-20th century is very likely due to the observed increase in anthropogenic greenhouse gas concentrations.”
Any unquestioning, policy maker is lead to assume that all increasing CO2 concentrations are progressively more harmful because of their escalating Greenhouse impact.
But that is not so.
From the present concentration of atmospheric CO2 at approaching 400 ppmv, only ~5% of the effectiveness of CO2 as a Greenhouse Gas remains.
Increasing CO2 concentrations certainly do not have the ability to save the world from a coming Ice Age, at the end of the Holocene likely this millennium.
Since the SST which regulates CO2 absorption, it is unlikely that the onset of the next ice age has anything to do with CO2 concentration.
The earth may not see another ice age on schedule, unless there is regression in evolution of Greenland-Scotland ridge. However, if the G-S ridge has not opened sufficiently to prevent it at some time in future (further along the Milankovic cycle), than a degree of submarine engineering on the ridge could do the job as outlined here
So the enormous hockey stick blade of Mann and Marcott must be greatly exaggerated (hyperbolic sarcasm). Do tell! Otherwise, we would have already prevented the next ice age. I think with climate sensitivity down to a third and dropping since the 2005 paper, we would need 3 times as much CO2 as stated IF CO2 INDEED CAN BE PROVEN TO BE AN IMPORTANT PLAYER AT ALL.
Anyway, I can see where this is all going – refusing to let go of CO2 as the “control knob”, we are in for a few thousand years of papers in Nature, GRL, PNAS etc. calculating how CO2 is carrying us through what would otherwise be an ice age. “Try to debunk this Mr. McIntyre!” they will be able to say. They’ll be able to extend the hockey stick blade to be longer than the shaft in a graph subtracting the temperature of a deep glaciation – science will be dead.
The true-believer syndrome merits study by science. What is it that compels a person, past all reason, to believe the unbelievable. How can an otherwise sane individual become so enamored of a fantasy, an imposture, that even after it’s exposed in the bright light of day he still clings to it–indeed, clings to it all the harder? –M. Lamar Keene
http://skepdic.com/truebeliever.html
It would seem that the AGW theory is ripe with folks who exhibit this malaise.
Doesn’t make sense.
shepherdfj says: April 27, 2013 at 7:03 am
“I have read that the only way to get us out of the Ice Age, in which we currently live and have so lived for that last 2.5 million years, is to remove the Isthmus of Panama. CO2 does not come into play with this equation at all.”
A more efficient way would be to block Drake’s Straigth. The Ice Age began when South America broke off from the Antarctic Peninsula, creating a circumpolar current, which made Antarctica a deep freeze.
Given that the atmosphere contains roughly 750 gigatons of carbon, and that CO2 flux between the atmosphere and the earth/oceans is something on the order of 150 to 200 gigatons a year, where do these absurd statements about fossil fuel CO2 remaining in the atmosphere for thousands of years come from?
More “models”? Are they counting only the specific molecules of CO2 (tagged somehow) that are produced by fossil fuel and not counting the rest of the normal flux? How do they get these numbers?
Seems to me, as a first approximation, that 5 to 10 years would be more like it.
A point I keep banging on about. At around the end of the 18th century, or thereabouts, it was assumed London would, in some years ahead, be swamped by horse manure several storeys high. I am an optimist when it comes to human ingenuity. Assumptions are often the key ingredient in failed predictions. Just ask Malthusians or peak oilers.
Here’s another geo-engineering project: Straighten up the Earth’s axial tilt by placing 2 mammoth nuclear-fueld jet turbines 180 degrees out of phase on top of very high lever towers – one at the north pole and the other at the south pole. Call it project Archimedes.
Not only can co2 prevent another ice age it can also cause Northern Hemisphere ice sheets to GROW! Oh noes! / sarc
Sorry, here is the link
http://www.nature.com/nature/journal/v355/n6357/abs/355244a0.html
No.
Ed Zuiderwijk says: (April 27, 2013 at 8:52 am)
“No, it will not. CO2 is not a climate driver.”
Exactly. CO2 follows warming; it doesn’t cause it.
With the evidence for little, no or even slightly negative feedback from clouds and watervapor, any level of CO2 and any change of it will have little or no impact on climate. Case closed imho.
Climate is driven by the sun, the oceans, cosmic rays, clouds and watervapor. CO2 has nothing to do with it..
Jimbo says
…and thus to ice-sheet growth.
henry says
global cooling will result in more arctic ice,
http://blogs.24.com/henryp/2012/10/02/best-sine-wave-fit-for-the-drop-in-global-maximum-temperatures/
count 88 years back, where are we?
http://wattsupwiththat.com/2008/03/16/you-ask-i-provide-november-2nd-1922-arctic-ocean-getting-warm-seals-vanish-and-icebergs-melt/
sounds familiar with recent reports?
remember by 1950 all had frozen back.
we will see the same again by 2040
but will man be ready for the coming cold?
Nope. But if we make this whole thing complicated enough, it may not matter.
scarface says
Climate is driven by the sun, the oceans, cosmic rays, clouds and watervapor. CO2 has nothing to do with it..
henry says
true
how do we get that msg out to the whole world?
I almost wish I had stayed in academia, but it probably would have made me a bad person.
I quote the philosopher Ray Stantz: “Personally, I liked the university. They gave us money and facilities; we didn’t have to produce anything! You’ve never been out of college. I’ve worked in the private sector. They expect results!”
Seriously, *basic* inconsistencies remain unresolved and the general response seems to be “shrug and move on.”
Nothing can stop the next ice age.. All we can do is migrate to the equator.. Luckily sea levels will be way down and we have the technology to live on and under the ocean..
What worries me more is now fast it will happen.. Its not like we can pick up and move nuclear reactors or storage, not to mention toxic chemicals or cities or garbage dumps.. The leading edge of the glaciers will be the largest imaginable toxic radio active dump, that will be next to impossible to contain..
When the melt comes this will run off into our smaller oceans..
Imagine the northern hemisphere scraped clean and ground up, running off into our oceans in a short period of time.. A ten year melt will pretty much deal with the leading edge and release it all..
IMHO a true environmental disaster that our oceans may not be able to handle..