The Earth’s Climate is Tracking into Uncharted Territory: A Note from Andrew Glikson
Posted by jennifer, September 2nd, 2008 - under Uncategorized.
Tags: Climate & Climate Change
Studies of Pleistocene glacial-interglacial cycles based on sediments and ice cores back to 640 000 years (640 kyr) document abrupt initiation of global warming and cooling events over short time scales of decades to a few years, implying extreme instability of the Earth’s atmosphere, with implications for 21st century climate change projections.
Current rise rates of atmospheric radiative forcing toward ~450 ppm CO2 are tracking toward an ice-free Earth.
Time tables of carbon emission reduction targets which take little account of the rates of ice sheet melt/water feedbacks and carbon cycle feedbacks, including release of methane hydrates from sea bottom sediments and from bogs, are unlikely to be able to prevent runaway global warming on a scale similar to the last glacial terminations.
Extreme climate change events in the recent history of Earth include:
A. Intra-glacial warming cycles, termed Dansgaard-Oeschger (D-O cycles), between 80 kyr and 20 kyr, including 21 ~1470 years-long cycles, each initiated over decades-scale time frames (Figure 1). The D-O cycles are attributed to interactions between weak solar radiation maxima and ocean current systems [1, 2].
Figure 1. An example of a Dansgaard-Oeschger abrupt climate event. 1 of 21 cycles during the alst ice age, 80 000 – 20 000 years-ago. Greenland ice core. From Rahmstorf, 2004.
B. Evidence for the last glacial termination based on deuterium and oxygen isotopes from the Greenland NGRIP ice core indicates sharp 3-years-long warming by 2 to 4oC at 14.7 kyr, sharp 1 year-long cooling at 12.9 kyr, and sharp 3 years-long warming at 11.7 kyr (Figure 2) [3].
Figure 2. deuterium-drived determinations of temperatures from Greenland NGRIP ice core for the period 14 740 – 11 660 years-ago, displaying abrupt warming and cooling changes between the ‘oldest dryas’ cold period, Allerod and Bolling warm periods, youngest dryas cold period and the Holocene. Note transitions occur over periods of 1 – 3 years. From Steffensen et al., 2008.
C. Evidence for the last glacial termination from the Greenland GISP-2 ice core, based on Nitrogen and Argon isotopes, indicates abrupt warming by 10±4oC at 12.8 kyr over a period of ~100 years and abrupt warming by 4±1.5 oC at 11.27 kyr over period of 70 years [4]. Sea level rose by 40 metres following the termination up to about 8500 years-ago [5].
Mean global temperature changes are estimated as about half the polar temperatures.
The origin of the D-O cycles is interpreted in terms of interaction between weak insolation signals and the thermohaline current system [2]. Glacial terminations at intervals of about 100 kyr, 41 kyr and 23 kyr (Milankovich cycles) were triggered by axial tilt toward the poles, elevating mid-June insolation by up to <60 Watt/m2 at latitude 65N [6]. The glacial terminations involved mean global solar radiation anomalies of 4 to 5 Watt/m2, triggering ice melt feedback loops and greenhouse gas release loops [6].
The intertwined synergy of these processes resulted in:
(1) Ice sheet and glacier melt, reduced short-wave reflection (albedo) by sea ice and ice sheets, exposure of water surfaces absorbing infrared, further melting of ice by warming water, migration of boreal forest northward causing decrease in albedo.
(2) Carbon gases (CO2, CH4) released from warming oceans, drying biosphere and fires; methane released from sea-bottom methane hydrates (clathrates: water-CH4 molecules) in sea bottom sediments and from drying bogs. Rapid release of methane hydrates is invoked as a mechanism for a runaway greenhouse effect and consequent mass extinctions through the history of Earth, specifically the Permian-Triassic (251 Ma) mass extinction and the Paleocene-Eocene (55 Ma) extinction (~ +6oC global warming) [7]
The combined radiative synergy of ice melt-feedback and greenhouse gases-feedback triggering rapid polar meltdown affected pole-ward migration of the inter-tropical convergence zone (ITCZ), subtropical arid zone and mid-latitude zones, affecting the ocean thermohaline circulation. The Greenland ice-melt flow result in abortion of the Gulf Stream which warms Europe and northeast America. Warming of the southern oceans weakens the Humboldt current west of South America and the trade winds, indirectly enhancing El-Nino events which result in droughts in the southwestern Pacific, India and Africa [8].
The rise in mean global temperature by several degrees Celsius over time scales of a few years to a century testifies to a high susceptibility of the atmosphere to minor to moderate energy forcings. According to Hansen et al. 2007 [6] the solar energy pulse from orbital variations which triggered the glacial terminations is up to 0.25 Watt/m2. Mean global atmospheric energy rise associated with the glacial terminations of +4 to +5 Watt/m2 (~ +5 to +7oC) are consistent with the upper range of the IPCC projections for the 21st century, +1.1 to +6.4oC.
Comparisons between abrupt glacial-interglacial terminations and 21st century projections are complicated by the lower mean global temperatures at which the glacial terminations commenced and the large volumes of ice compared to the Holocene, including the Laurentian and Fennoscandian ice sheets. The fast rise of the greenhouse gas forcing component since the mid-1800s, at rates since 1960 reaching 387 ppm in 2007 at rates of >1.6 ppm/year, are two order of magnitude higher than CO2 rise rates of 0.012 ppm/year at the last termination. Where 1 ppm CO2 induces an atmospheric energy rise of ~0.02 Watt/m2, this equates to an increase of 1.7 Watt/m2 in atmospheric radiative energy since 1750, not counting carbon cycle and ice melt feedbacks.
The non-linear nature of atmospheric CO2 and CH4 rise, from 1.3%/year in 1990-1999 to 3.3%/year in 2000-2006 [9], combined with further ice melt and albedo decline and carbon cycle feedback effects, including release of CH4 hydrates, drying/burning biosphere, reduced CO2 sequestration by the oceans, threatens to move the Earth’s atmosphere into glacial termination-like conditions. Rapid ice melt rates in Greenland, the Arctic Sea and west Antarctica, the latter continuing through the southern winter, are documented from satellite and on the ground. The polar ice sheets, initiated about 34 million years ago, when CO2 levels declined below 450 ppm, are in danger.
The Earth’s climate is tracking into uncharted territory.
Andrew Glikson
Canberra, Australia
Andrew Glikson undertakes earth and paleo-climate research at the Research School of Earth Science, Australian National University.
[1] Broecker, 2000. Earth-Science Reviews 51, 137–154;
[2] Braun et al., 2005. Nature, 438)
[3] Steffensen et al., 2008. Science Express, 19 June, 2008 ;
[4] Kobashi et al., 2008. Earth Planet. Sci. Lett, 268, 397 ;
[5] Siddall et al., 2003. Nature 423, 853.
[6] Hansen et al., 2007. Phil. Trans. Roy. Soc. London 365A, 1925. Hansen et al., 2008. Am. J. Sci (in press;
[7] Zachos et al., 2008. Nature 451 (7176): 279; Ryski, 2003. Geology; 31, 741;
[8] Trenberth et al., 2002). J. Geophys. Re. 107, 4065..
[9] International Carbon Project 2006. Recent Carbon Trends and the Global Carbon
http://www.globalcarbonproject.org/global/ppt/774,1,
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NT; you’re such a verballEr; I bet you haven’t even read the Chilingar paper; this one is bit simpler; just for you, and try to avoid any bad puns; more seriously, barry what do you think of Drake’s thesis?
But Louis we’d raise the tax free threshold and cut the dole. Thus forcing the newly fired science frauds and public servants to get real jobs.
And no its no comparative problem having them on the dole. They are cheaper that way and its harder for them to pretend to be experts.
As for Big Bang theory its only evidence for the idea that the very stupid are upwardly mobile in high physics as well as in many other areas of life.
I consider that rightful certitude comes from convergence. Whereas the very stupid seem to think that it comes from deductive or mathematical exactitude.
See how the idea that the universe is expanding and accelerating in its expansion rests on red shift alone. Thats pathetic when all is said and done. And one wonders how things could have fallen so far. They ought not have locked in the orthodoxy unless the distance of remote objects could have been calculated on the basis of at least two more methodologies. And they ought to have been on the lookout for reductions-to-absurdity that would tip them off to the fact that their reliance on a single line of evidence had been a risk that didn’t pay off.
The reductions to absurdity came thick and fast. But the academy was not predisposed to recognise them. With the singularity and the “inflation” theories intact, the received version of the Big Bang is clearly the most ridiculous creation story yet invented bar none.
It’d help if I gave the link;
http://homepage.ntlworld.com/jdrake/Questioning_Climate/userfiles/Ice-core_corrections_report_1.pdf
NT
“Ha ha, so there’s no more evidence for the Big Bang? Crikey, a lot of people take it seriously though don’t they? They must be mighty stupid.”
Evidence usually means observation of some physical phenomena – but as the Big Bang is before the appearance of anything capable of observing anything, and thus collecting evidence, your explanation is pure, 100%, baloney, as is your explanation for a imaginary atmospheric greenhouse effect.
I assume the initials NT are a compression of NitwiT.
Cohenite/Jan – for you guys (re Miskolczi etc)
Page 18
http://www-ramanathan.ucsd.edu/publications/Ram_ILEAPSnewsletter-apr08.pdf
For those who believe that the ‘Big Bang’ is gospel, reading this may give them pause for thought-
http://www.thunderbolts.info/thunderblogs/archives/mgmirkin08/060108_incorrect_assumptions.htm
but maybe not, for it takes a giant step to displace a belief
Julian,
Science is about explaining observations with known processes – in the Electric Universe case the equations of Lorentz and Maxwell can describe them in terms of, say, spiral galaxies.
Proponents of relatavistic theory need to invoke ad hoc additions to explain observation – black holes, dark matter, and other mathematical abstractions to make the belief work.
Empiricists are limited to what we know and according to the principles behind Occam’s Razor, EU theorists have a better explanation.
Thanks Steve; clouds throw a big shadow over AGW; your paper asks was Earth’s albedo always 29%; this paper speculates it wasn’t;
http://www.sciencemag.org/cgi/content/abstract/320/5873/195
The biological connection is interesting.
Cohenite… You keep linking to papers that use a Greenhouse Effect… This is getting embarrassing.
The stupid Barry Brook blog (bravenewclimate sick)
has an encomium today for the fatuous book by his mate, Ian Enting (Twisted). This claims that both Sir David King and James Lovelock predicted that by 2100 the human race would be restricted to a handful of breeding pairs in the ARCTIC. Presumably wewould have evolved by then into dolphins or polar bears. What jerks not to be aware, neither Enting nor Brook, that the Arctic has no landmass, and if they are to believed is already ice free. Enting also claims that King is a Brit, he is in fact originally South African (like me).
Tim, did you see the spray he gave Drongo?
Wow, that was a power serve!
NT; I have asked you what part of the blackbody differential of 33K you think is due to GHG’s, and you squibed it. I, on the other hand, think that GHG’s contribute to it; but in a miniscule way. I’ve said it before, so you’re still verballing.
I said I didn’t know… But I suspected it would be most of it.
I wouldn’t want to pretend I knew…
James Haughton said…”Replace light photons with IR photons, one mirror with the earth’s surface and one with the atmosphere, and you have a basic understanding of back-radiation. It doesn’t break the laws of thermodynamics, which apply to closed systems.
James…what does break the laws of thermodynamics is the flow of heat from the atmosphere at 0.25 C to the calculated 0.6 C average of the surface. Satellites are showing the atmosphere is 1/3 of the surface temperature and it has been pretty well established that the higher we go in the atmosphere, the cooler it gets.
You’re talking about heat flowing from the cooler atmosphere to the warmer surface. Unless you have an external means of doing that, like the motor in a refrigerator, you have the basis of a perpetual motion machine.
In this paper:
http://arxiv.org/pdf/0707.1161v3
it is explained why realclimate’s Rahmstorf’s has the concept mixed up. See Page 44 of 114 and 77 of 114.
The authors of the paper call his concept a ‘perpetuum mobile of the second kind’.
They go on to say:
***The second law is a statement about heat, not about energy. Furthermore the author introduces an obscure notion of “net energy flow”. The relevant quantity is the “net heat flow”, which, of course, is the sum of the upward and the downward heat flow within a fixed system, here the atmospheric system. It is inadmissible to apply the second law for the upward and downward heat separately redefining the thermodynamic system on the fly.***
It is understandable for the heat of the Sun to flow from a much hotter source to the cooler Earth’s surface but not from the cooler atmosphere to the surface, unless the Sun is heating the atmosphere to a higher temperature than the surface.
In fact. I am wondering if the model theory that a hot spot is being created in the troposphere due to CO2 warming is not based on that apparently faulty theory. The satellites are not showing that warming.
NT said…”The Large Hadron Collider. Yeah it’s supposed to give more clues about the Big Bang…”
NT…I didn’t know about the big hadron collider in the universe, so I guess that might explain the Big Bang.
You said something about red shifts being measured with an optical telescope. Do you know what they are? When atoms and molecules have transitions in their shells, they emit signature radiation at a specific frequency/wavelength. That spectra is normally collected with a radiotelescope but I imagine they have ways to do it with an optical telescope. It doesn’t seem like a great idea, however, since optical telescopes on Earth are not nearly as large as radiotelescopes. Their ability to collect that kind of radiation is limited.
When the spectra are collected, they are examined for their signature wavelengths. If they are shifted toward the red end of the visible spectrum, that’s a red shift, and if toward the blue end, that’s a blue shift. What can that possibly tell us about a Big Bang?
Red and blue shifts are Doppler shifts. In other words, if a celestial body is moving away, the emitted wavelength is at a lower frequency than it should be, and the difference is due to its relative velocity compared to us.
You put way too much faith in that kind of science. I’m not knocking the science because someone has to do the research and good on them for doing it. However, the amount of information out there is scant, and I’m afraid many physicists are claiming way to much knowledge for what is available.
I asked a question recently, “what’s on the other side of the universe”? Can you answer that, or can any scientists answer it? We haven’t the slightest clue as to the size of the universe, so how can we talk about a centre where a Big Bang might have happened? The relative motion measured by red and blue shifts is meaningless in the overall picture.
BTW, NT…a humourous story about astrophysics. On the first day of classes, I showed up to the lecture theatre only to find it over-flowing. I was disappointed because I had looked forward to the course and thought I might not get in.
I fought my way to the front and asked the prof what was up. He grinned and told me he’d sort it out fast when the bell went. When it rang, he called for quiet and explained to the crowd that the class was for astronomy, not astrology. He explained the difference. There was a huge groan and about 80% of the people left, most of them being arts students.
I don’t know why I had been looking forward to the class so much because it was about the driest class I have ever taken. It was all about calculating hydrogen gas, brightness and mass of stars, celestial mechanics, etc. It was interesting enough, but I was looking for a bit of sci-fi, which I quickly realized had very little to do with the reality of the universe.
The Big Bang Theory isn’t so much a theory as a totally baseless and mindless piece of work that would do fine as a reduction-to-absurdity.
But to what extent we can show the stupidity of the believers as correlated to the stupidity of the belief is a matter entirely other.
This is where idiots like you are coming off the beam NT. You look for everything to be evidence except for actual evidence.
Only evidence is evidence. And non-evidence is not evidence.
Whether really brainy people believe in various stupid beliefs is not evidence for those stupid beliefs.
Plus its instituionally harmful for idiots like yourself to be encouraging people to substitute the alleged beliefs of allegedly brainy people for evidence.
All that this is evidence for is that allegations exist that brainy people believe this or that.
This is not evidence for the proposition at all. But only evidence for the allegation that certain people hold certain beliefs.
And since the person I’m arguing with might be one of the creators of these allegations of beliefs we see ourselves getting further and further away from actual evidence.
Can you find evidence for the Big Bang NT? No you cannot. So your belief amounts to a mindless superstition.
But its worse than that. Because the Big Bang as presented is far more stupid than any other creation myth yet invented.
Jen, your pics have gone from this post.
link
Hope your break in Japan was good for you. Seems to have been an enjoyable trip.
:-)
Clothcap
Belay that, they just appeared after commenting. Must be a browser/server glitch!
As you were.
:-)