The International Geological Congress (IGC) is sometimes referred to as the geologists’ equivalent of the Olympic Games and is an extremely large gathering of geologists from all over the world, taking place at 4-year intervals. This time, the IGC took place in Lillestrøm, a small place just outside Oslo, Norway (August 6-14). The congress was opened by the Norwegian King (before he continued to the real games in Beijing), and was attended by some 6,000 scientists from 113 countries. Even the Danish Minister of Energy & Climate participated in a panel discussion on climate change. In other words, this was a serious meeting.
I didn’t attend the meeting myself, but the scientific programme for the session on climate, shows that the ‘climate contrarians’ were quite well represented. The organizers probably wanted to give room to “other views”. Together with web cast of the panel discussion on climate change (by the way, you may need Windows to view this because of the video format…), the proportion of attendees with a skeptical attitude to the notion of anthropogenic global warming appeared to be notably higher than in other conferences, such as the European Geosciences Union or European Meteorological Society, or indeed the scientific literature. So be it.
Svensmark was there, even though he’s not a geologist, and said that he didn’t understand what he was doing on the panel. He didn’t say much during the panel debate, apart from that clouds are not well described by GCMs (which is true and discussed in the latest IPCC report), and that the 90% confidence in the human influence on recent trends is derived only from models (not true). There is an irony in that, whereas detailed microphysics in clouds are not well understood (hence the uncertainties in the GCMs), Svensmark’s own hypothesis hinges entirely on the cloud response to cosmic rays (which is even less well understood).
Robert Carter said a great deal more than Svensmark on the panel. He made a point of the last couple of years being cold. But he did not appear to understand Jansen’s explanation of the difference between trends and natural variability (see here). What really struck me was not who was saying what, but the intellectual level of discussion: the debate often got stuck at misunderstood trivialities which for a long time have been regarded as solved or explained in the climate research community. When you keep starting at square one, you’ll never make much progress.
Other statements did not have a scientific basis (e.g. Morner popped out from the crowd and said that the sea levels are not rising – not true – and then saluted the panel). Thus the debate seemed to be a step backwards towards confusion rather than a progress towards resolution.
What is going on? Is there a higher proportion of geologists that have a completely different view on climate change, or was this a biased representation of the community? The thought of stifling a scientific debate by insisting on outrageous or ignorant claims also has struck me.
Update: Marc Roberts sent along this mildly relevant cartoon:
YouTube offers some wonderful video squabbling over the subject of creationism.
Some great videos debunking Top 25 Creationist Fallacies
A very serious use of YouTube.
http://www.youtube.com/watch?v=EXMKPvWqgYk
Professional Denialism v. Climate Destabilization studies needs this kind of fun stuff.
Re 148 –
If the semimajor axis stays constant (not sure if that’s true or if that’s part of the cycle), then – I have a calculation for the annual average TSI change. I’ll get it out tomorrow. I can say from memory that it’s very small, though.
The most familiar explanation to me for Milankovitch – glaciation forcing is that when the various Milanovitch cycles line up in some way, high latitude regions may have reduced seasonal variation, so that winters may be more wet, with increased snowfall perhaps, and – perhaps more importantly? – the summer doesn’t get warm enough to melt all of the snow from the preceding winter. When that happens the snow can accumulate over years, and then the ice-albedo feedback causes a global cooling, and then the CO2 feedback kicks in, etc. And then when the summers get hot enough, the reverse may occur. Precession has the opposite effect on each hemisphere, but it is the Northern Hemisphere that currently has the most land at the right latitudes available for continental ice sheets (aside from Antarctica which remains glaciated during the interglacials), so the glaciation/deglaciation process may be most sensitive to forcing in the Northern Hemisphere high latitudes. But there are complexities…
Among those complexities:
Considering the threshold of Milankovitch forcing which, when crossed in one direction, could trigger an ice age, will not generally be the same threshold to cross in reverse to trigger deglaciation. This is in part because of the albedo and greenhouse gas feedbacks that would tend to maintain the Earth in one or the other state. There are also other factors – the surface of a thick ice sheet, even after isostatic adjustment of the crust to the weight of the ice, is at a higher elevation than the surface on which it first formed – thus it will tend to be colder, even without the albedo feedback. The height of the ice surface is influenced by how rapidly the ice sheet spreads out under it’s own weight and by how rapidly additional ice is added over time. The rate of spreading may be faster if there are loose sediments underneath – in a series of ice ages, the first few ice sheets may spread out more rapidly because they have not yet scoured away the lubricating top layer of sediment and soil (this might have something to do with the change in ice age duration around 900,000 years ago (or is it 700,000 years ago?)).
If the land surfaces at the ‘right’ latitudes are too large, they may not recieve enough moisture in the winter to have remaining snow cover at the start of the next winter. Also, larger continents tend to have more extreme seasons.
And then there’s the ocean currents…
Over at The Oil Drum is another view of this conference from Charlie Hall (a good guy on energy issues and other things). See comments #9 & #10 in particular, i.e., a an outsiders’ view of the fights.
BTW: the sort of work Charlie does is really important on the economics of climate change: if he (and Bob Ayres & co) are right, the happy several-percent CAGR in world GDP baked into the economics models … is not going to be so easy.
I have a tangential sandbox-1 question (or clarification) re Milankovitch cycles. If the long (major) axis of the ellipse increases does not the minor axis have to shorten to maintain/conserve momentum?
RE #155 Rod B,
Wikipedia – Milankovitch Cycles says “the semi-major axis is an adiabatic invariant” i.e. it does not change. So as the Earth’s orbit becomes more circulat the minor orbit must increase. This means that the total solar energy reaching the earth over a year decreases. That, added to the effect of the other orbital orbital cycles can lead to a glacial period in the current ice age.
HTH,
Cheers, Alastair.
RE #155
John,
I reckon we should be honest about this.
In #9 Charlie Hall wrote:
So there was not much difference between the two sides :-(
And in #10:
Even if “Earth has never seen CO2 levels such as we are headed for” is an exaggeration, it is still sound pretty catastrophic to me.
However, I think that the killer point was made in #11:
Let’s face it. We are all stuffed. The geologists won’t admit it but neither will the climate scientists. Let’s face it The geologist are not different. We are all denialists :-(
Cheers, Alastair.
Don Healy: “Another question that comes to mind is if earth did not experience a runaway greenhouse effect when CO2 levels were 4000 ppm or higher in earlier geologic history, what has changed to create such alarm at levels ten times lower?”
Earth is not in the same position relative to the arms of the galaxy, the continents have been moved around, and there are about six billion extra people in attendance expecting to get fed and watered.
Other than that? It’s exactly the same.
For constant semimajor axis, total energy is conserved; Angular momentum of the orbit is proportional to the square root of (1-e^2), where e is the eccentricity.
If I did the integral and algebra correctly:
TSIave = TSIa * (1-e^2)^(-1/2), where TSIave is the annual average TSI and TSIa is the TSI at the distance from the sun of the semimajor axis.
Notice that for small e,
(1-e^2)^(1/2) ~= 1 – (e^2)/2
(1-e^2)^(-1/2) ~= 1 + (e^2)/2
So that, relative to an eccentricity of zero, the percent decrease in orbital angular momentum L and percent increase in TSIave are approximately,
for each e:
e, %
0, 0
0.01, 0.005
0.02, 0.02
0.03, 0.045
0.04, 0.08
0.05, 0.125
0.06, 0.18
0.1, 0.5
The Earth’s eccentricity varies between about 0 and somewhere between 0.05 and 0.06 – rounding up to 0.06, that’s a 0.18 % change in annual average TSI at the distance of Earth. Applying the same percent change to the absorbed solar power per unit area of Earth, that’s a global annual average of about 0.43 W/m2. Notice that the annual average TSI increases with increasing eccentricity.
If not for the geographical variations of albedo, the obliquity and precession variations would have zero direct effect on global annual average (the geographical variation could have the effect that when a greater fraction of sunlight is concentrated on snow and ice, there would be some global average decrease in absorbed insolation. Yet over time such a distribution (depending on seasonality) might cause the ice to melt back, so it’s conceivable that the Milankovitch forcing that would end an ice age might initially cause global cooling – maybe?
The fractional seasonal range in TSI and absorbed insolation should be close to 4*e for relatively small e values, so a 0.06 eccentricity would lead to a global average seasonal range of about 24% of the value at the semimajor axis. Factoring in albedo, that’s a seasonal range of forcing of about 58 W/m2, globally averaged. Precession can also have a large seasonal effect, and that is modulated by eccentricity. When the precession and direct eccentricity effect are opposite in one hemisphere, they will work together in the opposite hemisphere.
“Precession can also have a large seasonal effect, and that is modulated by eccentricity. When the precession and direct eccentricity effect are opposite in one hemisphere,”…
Actually, when the eccentricity is zero, the Precession effect is zero as well – the seasonal Precession forcing includes the direct eccentricity effect on seasons.
Thank you realclimate, for this great blog topic. As a scientifically-trained climate amateur I had noticed the physics or earth-science backgrounds of many of the “science-qualified sceptics” quoted in the press, and had wondered why (apart from the obvious industry link). This helps cast some light on the phenomenon. The average person has little hope of grasping the significance of these mental nuances at present. Comparative research into the cognitive processes of scientists in different fields could be an interesting study.
As a retired geologist with a critical attitude towards IPCC and the climate scare, I would like to add my “pennies worth”. Unfortunately my financial status is not firm enough to have travelled to the IGC and the webcast does not show up on Mozzilla Firefox, so I have to rely on what has been written above.
It is pointless to compare present climate to that of 10s or 100s of millions of years ago. Firstly data is very scarce and the temporal resolution of this scarce data is even worse.
The postglacial (Holocene) time is a much better key of the past to understand the present.
The sea level was 120-130 meters lower than today before the end of the last glaciation. The end of the glaciation and the following few thousand years saw large fluctuations in sea level as well as temperatures.
It is also most probable that the Holocene Climatic Optimum was clearly warmer than today. During the millennia that followed climate has been very variable and has had severe influences on past civilisations. Brian Fagan has written three excellent books on the role of climate: Floods, Famines and Emperors – el Niño and the fate of Civilizations; The Little Ice Age – how Climate made History 1300-1850; and The Long Summer – How Climate Changed Civilization.
I should add that I do believe that man has in the past, does now and will also in the future influence climate due to poor environmental management, land use changes and naturally population increase. This influence is, however, still on a local or regional level – NOT GLOBAL.
I also oppose the idea that CO2 is such a monstrous culprit as portrayed by IPCC followers. Here I fully agree with Bob carter when he states that CO2 follows temperature changes, so it can not cause them, at least not in any significant way.
There was also a comment comparing geological modelling with climate models. I would like to point out that geological modelling can be useful, because geology is a rather simplistic science while climate is a horrendous and complicated mixture of various inputs and outputs and processes of which science has been able to define only a part, the rest being dependent on intelligent guess work and parametrization.
Boris Winterhalter: Spoken like a man who hasn’t looked into the science of climate very much. Start here:
http://www.aip.org/history/climate/index.html
The oracle of ReCAPTCHA: unaware moved
Boris, #162
If we have a local effect on weather and climate then because we are all over the globe, surely this turns it into a global change.
Any how do you arise at the idea that CO2 can only ever be a result of warming rather than a cause? E.g. what about temperature *causes* CO2 to rise? And why does that mean CO2 rises *cannot* cause a temperature change?
How do you think parameterisations get made? Are they all made up or are many the result of microclimate simulation giving the “per big block” equivalent result and avoiding the need to model the microclimate just to get the macroclimate? Do the scientists say “we have to get a warming of 2-4 degrees by 2050 so what numbers should we put in to get that result?”?
Statements like this must make climate scientists, atmospheric physicists, and the like just want to bang their head into a pulp on the nearest brick wall …
[Response: Not quite… but it does give a clue as to whether you are dealing with genuine scepticism or simple denial. One engages or not depending on the conclusion. – gavin]
Ray! I disagree, I consider myself at least somewhat versed in climate science and am familiar with IPCC ever since the first report. After retiring in 2002 climate science has been my major pastime and I do believe I am able to understand the issue. I agree, that climate science has developed considerably and as the vice-director of the Finnish Meteorological Institute is is to a some extent thanks to informed sceptical input.
Mark, I am sorry I should have been more specific. I agree, that combining all the local influences will probably show an impact on a wider scale. However, not all the local impacts like urban heat island effects, forest clearing, waterway changes, etc can be assumed to influence the climate in an unfavourable manner, but on a global scale my view is that the effect is hardly noticeable.
Sure CO2 is a greenhouse gas and comes second after H2O. If you look at the IR absorption wavelengths you will notice that CO2 covers a few rather narrow bands while water vapour covers a considerably larger band width and is thus a much more important GHG, especially near the surface and the troposhere. Where an increase in CO2 comes becomes a very important climate agent is in enhancing the heat escape to space, because as you obviously know only GHG’s are capable of radiating out energy (heat) into space. I should add that the upper atmosphere is rather dry so water vapour plays only a minimal role.
Regarding modelling, I must confess that I have never been fond of models trying to mimic nature, and climate as such is far too complex to be reliably modelled at our present level of knowledge and the reliability of data, e.g. global albedo and actual solar energy heating up the surface, relationship between up-welling and down-welling energy fluxes, etc.
I would also like to see how the models would explain fluctuations in past climate as e.g. mentioned in Brian Fagan’s books.
[Response: That is all much more sensible and open to reasonable discussion (though see these posts for answers to your IR questions). So why did you start off by using the extremely lame ‘CO2 lags, doesn’t lead’ argument? You are well aware that is logically incoherent and completely compatible with a major role of CO2 in the current warming. You’ll probably find that your serious questions are likely to be more seriously addressed if you leave the tired contrarian talking points at home. – gavin]
Patrick (159-160), Thanks for the helpful response. (Alastair, too.) I have one remaining question (which is making me feel stupid for missing maybe the obvious fundamentals…), but how is it that the angular momentum of the Earth relative to the Sun changes at all in the first place? Not including the miniscule continuing decrease caused (I think?) by the gravitational tidal force (torque), but the change in angular momentum that cycles up and down. How do it do dat?
Boris, It is clear from #166, that your understanding of the physics of the greenhouse effect is rather confused. Yes, it is only the greenhouse gasses that radiate high in the atmosphere, but that is because the IR radiated from Earth outside the GHG bands escapes unimpeded. I suggest:
https://www.realclimate.org/index.php/archives/2007/08/the-co2-problem-in-6-easy-steps/langswitch_lang/bg
https://www.realclimate.org/index.php/archives/2007/06/a-saturated-gassy-argument/langswitch_lang/bg
https://www.realclimate.org/index.php/archives/2007/06/a-saturated-gassy-argument-part-ii/langswitch_lang/bg
CO2 is unique in that: 1)it stays well mixed in the atmosphere well into the lower stratosphere; 2)it perissts for hundreds to thousands of years. 3)Its concentration is increasing rapidly due to human activity.
You say that climate science is a major pastime–so why not learn how the mechanism works rather than constructing straw men?
#166 re: Gavin response
Gavin since you, or the other powers the be closed the topic of the CO2 lag here on this site awhile back ; after only a few responses I find your “lame” comment over the top! BTW my husband read the explanation given by RC there and found it “lame” too, to use your own word. And he showed it to his fellow co-workers at the time for a chuckle. Why don’t you open it up?
[Response: Old comment threads attract nothing but spam, and so they are just closed. The topic has been discussed numerous times since then (most recently here), and I doubt there is very much new to say. We’re happy to provide amusement for your husband and colleagues, but I’m rather surprised that the concept of ‘chickens and eggs’ seems to be a novelty for them. – gavin]
Yes Gavin, and that link refers in this paragraph:
“Of course, those who’ve been paying attention will recognize that Gore is not wrong at all. This subject has been very well addressed in numerous places. Indeed, guest contributor Jeff Severinghaus addressed this in one of our very first RealClimate posts, way back in 2004.”
to this page:https://www.realclimate.org/index.php/archives/2004/12/co2-in-ice-cores
4 whole comments allowed!
[Response: We didn’t have as many commenters then. Now the same post would garner a lot more. But what do you want to actual say? Discussing comment thread policy from almost 4 years ago is not particularly interesting. – gavin]
Re 167 –
I can explain the causes of prececession and have an idea of what might cause obliquity variations, but I’ve never been clear on the eccentricity cycle – except that it must involve the relatively weak (compared to planet – sun) gravitational interactions among the planets.
I also made something simple into something rather complicated when I last mentioned precession and eccentricity. The effect of precession IS the seasonal timing of the effect of eccentricity.
Boris, #166, But what you have is models: there IS no “gravity” but what change do we get in energy levels when within the influence of a large mass has an effect we *model* as gravity.
That “gravity” as we know it doesn’t exist is shown by the incontrovertible FACT that we have two different ways of explaining “gravity” and we can’t get them to meet. Since they do in real life, we know the models are wrong.
But we can STILL use models of even the known erroneous Newtonian gravity to hit a target only a few thousandths of a degree across in a distance of half a billion miles.
All by “mimicking nature”.
Computer models are more simulation: given a model of the atmosphere that includes the “models”:
a) fluid motion of a gas(and hence the plethora of gas equations and fluid motions equations)
b) quantum models of how gasses react to radiation spectra
c) the model that if we run discrete steps of our simulation forward through time that this will approximate reality which knows no such quantisation
we simulate what happens in the earths atmosphere, hydrosphere and biosphere.
***Simulate***
If you want, have a look at some of the older “Flight Gear” flight sims on the PC: they used a simulation to model how a light aircraft will act. Microsoft Flight Simulator however uses a model that says things like “at x AoA thrust and drag will cause this loss of power in motion along the line of flight” and other such empirical rules.
You seem to think climate models are entirely of the MS Flight Sim type. Well the truth is it is mostly (now) of the first type. It gets more simulation as we get more computing power available and some of the parameterisations are removed as we can find enough power to usefully *simulate* how an ideal gas (the model) will act.
I would suggest you learn what goes into modern climate models before you make assumptions on what they do.
“All models are wrong. Some are useful” — statistcian George Box.
see the Wikipedia article on Milankovitch cycles for clear definitions of precession (due to the earth’s ‘waistband bulge’) and eccentricity, and tilt changes.
The Milankovitch cycles provide beautiful correlations with astronomical changes and climate changes but do not provide detailed breakdowns of cause and effect in between. The solar insolation changes seem to be amplified by features of the earth.
Which is why paleoclimate findings cannot be applied to the present. We – humans – have changed several features by adding 1/3 more CO2 to the air, deforesting large areas, etc. Feedback mechanisms are now occuring: global warming got started with more CO2 etc, causing open water in the Arctic in summer, which absorbs more sunlight instead of ice reflecting it back into space, causing further warming. Or, melting of the Russian peat bogs is releasing methane gas, a potent greenhouse gas.
Bob Carter, it seems possible that astronomical forcing started the paleo-warming, which caused the ocean to release carbon dioxide, further increasing warming. Whatever happened in before people, carbon dioxide has increased hugely in the last 50 years and this will absorb more heat, and this has been known for 150 years.
Re 166 – you might find my explanation at:
http://blogs.abcnews.com/scienceandsociety/2008/07/tropical-storm.html
(If you want to get straight to the greenhouse effect physics, go to the comment immediately after “Jul 16, 2008 12:34:05 AM” – PS I found it helpful to refer to Ray Pierrehumbert’s online draft copy book … the overall conversation continued for a brief while at http://blogs.abcnews.com/scienceandsociety/2008/07/global-warming.html )
-helpful – I like to try to explain the greenhouse effect using visulization (pretend you can see at any wavelength you want, and then think about what you would see.)
Also keep in mind some shorter IR wavelengths, from ~ 4 microns to red light, are dominated by solar energy and have little to do with the greenhouse effect. I think there’s been some confusion (Fred Singer, Richard Lindzen perhaps?) stemming from looking at the effects of H2O and CO2 in the solar IR wavelengths. I’m not saying H2O isn’t an important greenhouse gas – instantaneously it is, but it (and clouds) varies rapidly in response to weather, so CO2 is and has been for much of Earth’s history (exceptions being when CH4 was dominant, perhaps particularly in the later portion of the Archean) the dominant climate-regulating greenhouse agent.
Patrick, “….the eccentricity cycle…must involve the relatively weak (compared to planet – sun) gravitational interactions among the planets…” makes intuitive sense to me.
Ray (#168), I am confused, but not so much due to physics, but due to the fact that people with the same level(?) of understanding of physical processes can have so diverging views on climate change, like antipodes, e.g. RealClimate and Climate Audit.
[Response: The person (Steve McIntyre) behind Climate Audit is – to the best of my knowledge – not a physicist, but an economist. I personally doubt he understands the physics of the atmosphere/oceans. -rasmus]
The lifetime/residence time of a CO2 molecule in the atmosphere is according to 14-C studies following nuclear bomb tests was calculated to 5-7 years (Minze Stuiver, pers,comm). I agree that radiocarbon differs slightly from 12-C in its biological cycle, but anyhow does show the rapid exchange. IPCC does agree that carbon has a short lifetime, but it really has an undeterminable lifetime which can extend to millennia??? There was a passage in one of the drafts for 4AR that the long lifetime is due to rapid exchange with the oceans and the biosphere, but the same holds true for H2O.
[Response: You are confusing residence time in the atmosphere with the perturbation time in the atm/biosphere/upper ocean. David Archer explains this well. – gavin]
Patrick (#175), thanks for the link to Science and Society. I will try to digest the lengthy texts.
Regarding the longer wavelengths in the IR, I am sure that neither Fred nor Richard have confused the short IR from the sun with the black body radiation of the surface.
I disagree with your view that CO2 is the dominant climate regulator. No matter how you look at climate, water in its different forms is absolutely the major regulator. Roy Spencer’s views at http://www.weatherquestions.com/Roy-Spencer-on-global-warming.htm#greenhouse3 are thought provoking and very logical.
The fact that H2O molecule has a short lifetime, the fact is that there is always moisture (magnitude naturally dependant on locality, etc.) in the air. Weatherwise H2O varies, I agree, but we are discussing climate and not momentary weather. In climate the GHG effect of H20 is integrated over the entire globe and over a long time period and this puts the water molecules in the front as the major GHG.
Boris posts:
In a natural deglaciation, carbon dioxide does indeed follow temperature at first. But your “so it can not cause them” is a pure non sequitur. Carbon dioxide is a greenhouse gas. The sunlight variations due to Milankovic cycles are not severe enough to induce the temperature changes which actually happened; you need the carbon dioxide as an amplifier.
In addition, carbon dioxide is NOT following temperature NOW. This isn’t carbon dioxide given off by the ocean in response to a rise in ambi-ent temperature; the ocean is still a net carbon SINK, emitting 90 gigatons of carbon a year but taking in 92. The new carbon dioxide around us is primarily from burning fossil fuels, as is clear from the radioisotope profile. The radioisotope signature of fossil-fuel CO2 was first detected in ambi-ent air by Hans Suess in 1955.
Carbon dioxide is a greenhouse gas. Denying that is denying well-established science, and it’s hard to believe that a professional geologist, emeritus or not, would be unaware of the Faint Young Sun paradox, Walker et al. 1981’s explication of the carbonate-silicate cycle, and Berner and Lasaga’s work on the carbon cycle.
Veritas — the precession referred to in Milankovic cycles is the precession of the longitude of perihelion of Earth’s orbit, not the precession of the Earth’s axial obliquity. I made the same mistake at first. The problem is that most sources, especially on the web, just use the word “precession” to mean both processes.
Boris Winterhalter, My criterion for who understands climate has to do with how many publications they have on the subject in peer-reviewed scientific journals and with how often their research gets cited. What’s yours?
Your view of the greenhouse effect is confused because you are not taking into account adiabiatic cooling of the atmosphere. Your view of the lifetime of CO2 is skewed because you are not taking into account that CO2 that goes into the biosphere and upper oceans does not leave the climate system. Rather myopic for a geologist. Boris, you have a choice. You can keep arguing against straw man constructions of your own imagination or you can learn the actual science. This site is an excellent place to start on the latter. If you choose the former, you will find more kindred spirits among the crew over at CA.
Boris, water cannot be the major regulator: it too easily moves phase.
When it comes to transporting energy, water is a far better mechanism than wind or anything else because of this mobility.
But transporting the energy is not the regulator any more than the gulf stream is.
For instance, how can it regulate the temperature when it can only exist very temporarily before it, for example, falls out of the sky? It cannot cause more cloud than uplift allows and a low level cloud increases insulation where high level cloud increases cooling. Clouds can do either and there’s no mechanism that requires it only manifest in the “right” way to make your argument.
Boris also check out
https://www.realclimate.org/index.php/archives/2005/04/water-vapour-feedback-or-forcing/
Also available via the side bar under the Highlights section.
Dave
#177 Boris Winterhalter
Here are a some keys to understanding the difference between natural cycle and anthropogenic global warming.
Please pardon my rounding of the numbers but I am merely doing this for illustration reasons.
Atmospheric composition, forcing levels, and GHG’s and of course the sun. Lastly to get it in perspective oceanic thermal inertia.
ATMOSPHERE & GHG’s
Our atmosphere is mostly nitrogen and oxygen and pre industrial about 1% other trace gases. Of that only 280ppm was Co2 combined with methane 715ppb and nitrous oxide 270 ppb. Then you add the variability of H2o
So other than H2o less that 300 ppm of our atmosphere was keeping us from being a big frozen ball. So quantitatively it seems like a small amount but the actual composition change of the total of GHG’s is huge. Remember, the majority of the atmosphere does not warm us at all. It’s only that little bit of GHG’s that trap the heat and we have altered that amount strongly.
Since we have added additional GHG’s getting us closer to 400ppm increases the heat trapping capability.
Note on your Co2 longevity question: From what I’ve read in the most recent studies, Co2 can hang out for quite a long time but a lot of it maybe around 75% will come out of the atmosphere within 500 years. The rest lingers. But that means that unlike the other gases which apparently don’t hang out as long, that our biggest problem re global warming is Co2. Because it warms and hangs out for a long time.
So we add GHG’s and go from say 300ppm to 400ppm and that warms the ocean. That means more evaporation thus increasing the H2o level on average. While relative humidity remains around 80%, the quantity of H2o is increased so we get further warming. This feeds back to warmer oceans along with other factors and thus evaporates more H2o etc.
FORCING LEVELS & TSI on EARTHS SURFACE
All these gases have a forcing component that is positive. Aerosols and particulates have a negative forcing component. We have added both but our positives are outweighing our negatives.
Since we receive on the planet surface around 240 W/m2 and radiate about the same into space we we stay in a dynamic equilibrium within natural variability and the imposition changes of the Milankovitch cycles.
pre-industrial forcing was around 0 to -.1 W/m2. Now we have increased the positive forcing about around 3.7 W/m2. but we also increased negative forcings around -1.7 W/m2 resulting in a climate forcing of around 1.9 w/m2. Since a normal interglacial is usually around, at it’s peak, 0 to .3 W/m2. We are largely outside of the scope of natural forcing at this time.
OCEANIC THERMAL INERTIA
The ocean heats and cools slowly. If you turn on the heat in your house and in your swimming pool, the house heats up faster.
It will take time for the ocean to absorb the forcing imposed on the system and since Co2 is going to hang around for awhile expect warming for centuries if nothing is done.
IN SUMMARY, consider the rate of change with is unprecedented our atmospheric GHG change rate is probably between 7000 and 14,000% faster than natural change rates. Consider latidudinal and altidutinal climate shifts and the species extinction rate. Consider the interruptions to the food change and the acidification of the oceans (the foundation of the food chain, which we are converting to dead zones by virtue of nitrous oxides and red tides with massive algal blooms… don’t forget the jellyfish blooms though, we are killing all the fish by multiple means.)
This global warming event is doing some dramatic things to the earths eco/bio systems. Lastly, don’t forget, we are part of that bio system as a human race and we will be affected. This is just the beginning.
Ray (#180), you are sticking to an old mantra, that only peer-reviewed scientific papers are valid proof of proper understanding of an issue. Scientific thinking and publishing are too different things. Some people who’s ideas I cherish have never published a line, but are still considered by many as top thinkers. Most publishing today is connected to funding. Unless you publish, you can’t apply for funding – it’s simple as that. During my active years as a marine geologist I have published sufficiently both in peer reviewed journals and classified reports. The work I have done, e.g. in the Baltic Sea was not deemed of global interest, but it was surely noted within the local scientific community.
You accuse me of not taking into account adiabatic cooling. Where did you get that idea? You write that my view of the lifetime of CO2 is skewed. You argue that CO2 that goes into the biosphere and the upper oceans does not leave the climate system. Does this not also apply to water molecules??? [edit – keep it constructive]
Mark, David, John etc. I give up. I knew of the IPCC believer views of Gavin and Rasmus, but I thought that there might be some griound for discussion with others, but I find it useless, because we all stick to our predetermined views and the comments I have received have a tendency to take words out of context.
I am signing off!
#185 Boris Winterhalter
I don’t understand? I am not using predetermined views at all, in fact these are developing views. And as more science is examined, newer views will emerge.
It sounds as if you are the one who is predetermined?
I’m not even sure what you are trying to say. Are you saying this global warming event is either not human caused of less caused than certain science agencies are stating?
If so, please do enlighten us. I’m betting lot’s of folks here are looking for a good reason to move on to other interesting subjects rather than global warming.
Personally I’d rather be working on healthcare and education, but this subject seems to be trumping even those from what I can see.
So if you do have sufficient evidence to prove it’s not human caused, please present the case so we can examine it. That would be very much appreciated.
Boris, Adiabatic cooling is the reason why greenhouse gasses are a net positive for energy and not neutral. And I’m sorry, if it isn’t published in a peer-reviewed scientific journal and cited in subsequent work, it doesn’t advance the science–you ought to know the rules as well as I do. I know of not one single scientist who advanced the state of science without publishing. As to the difference between water and CO2–water hasn’t increased by 40% during the industrial age.
You have choices, Boris. You can try to publish something that refutes the consensus science–good luck. You can try to actually learn the science behind the climate so that your criticisms are at least relevant to the real consensus science. Or you can continue to ignore the science and attack your straw men. We can only help you with one of those things here.
Dr. Winterhalter has an extensive website detailing his current understanding and beliefs about the science and politics; he’s concerned about ‘environmentalists’ in particular it seems. Check there for his sources and philosophy about what constitutes evidence.
Re Boris – in case you’re still listenning:
Water vapor vs CO2:
Consider what happens if I throw a bunch of water vapor and a bunch of CO2 (additional to whatever was there) into the air at some time and then sit back and watch.
Both will have a warming effect initially. But it takes time for a radiative forcing to produce a temperature change because of heat capacity. So the temperature doesn’t change immediately
—(it will adjust relatively quickly in the upper atmosphere* (*stratosphere and above) because it isn’t so intensively convectively coupled to the ocean as the troposphere is (as a quick back-of-the-envelope estimate, the upper atmosphere maybe somewhere around 2,000 kg per m2 at ~ 1004 J/(kg K) => heat capacity of ~ 2 MJ/(m2 K), versus the upper ocean ~ 70,000 kg/m2 * ~ 4000 J/(kg K) = 280 MJ/(m2 K), + about 8 MJ/(m2 K) of troposphere…, so the upper atmosphere should approach an ‘equilibrium’ temperature about 150 times faster than the troposphere and upper ocean – but that equilibrium itself depends on tropospheric and land and ocean temperatures, so that doesn’t mean the upper atmosphere doesn’t continue to readjust along with the whole climate system… So if the climate system took ~ 10 or 20 or 30 years to approach an equilibrium (outside of slow acting CO2,CH4,ice sheet,vegetation feedbacks), the upper atmosphere would approach ‘equilibrium’ in ~ 3 or 7 or 10 weeks). —
The water vapor I added will get mixed around by the air motions, condense, and precipitate out of the air. In a timescale of ~ 10 days (perhaps still faster than upper atmospheric response times), it has come out of the air. Is there more left in the air than before this experiment started? No, because that’s regulated by temperature and circulation patterns – (circulation patterns vary independently over short time periods but they are regulated by climate conditions over long time periods so on average they shouldn’t have an effect on average on whether or there remains much of the water vapor added over 10 days ago…) – the water vapor comes out before it had a chance to cause much climate change (if it did cause some change in the upper atmosphere, the upper atmosphere would again change back to adjust to the conditions in the troposphere and surface). Maybe if the water vapor went into an otherwise dry region and precipitated there, that would increase the wet area of Earth and so prolong an increased water vapor content, but that kind of thing can only last so long…
So in order to force climate by water vapor, it has to be continually added. Maybe the increased evaporation by continually irrigating otherwise dry regions may have some small effect…? Certainly the area of the oceans (and maybe positioning of them) has some effect on water vapor content, but either way, SOMETHING has to prop the water vapor forcing up – the water vapor is an intermediate by which some other forcing works in that case…
In contrast, CO2 takes a few years to come out of the atmosphere. BUT – where does it go? The oceans and vegetation, and through vegetation, soil. Has the total C content of oceans, vegetation, and soil increased? If not, then during the same time period that the CO2 molecules I added came out of the air, the same number of CO2 molecules were added back into the air – not the same molecules, but the same number of molecules.
In reality, in response to adding CO2 to the atmosphere, before the climate itself responds, the oceans and vegetation do take up more CO2 than they release, but not so much as to bring the CO2 level down to where it was before, at least not in anywhere near the same timeframe that the original added CO2 molecules were taken up (my impression is that there is an initial rapid response that take up ~ 40% ? of added CO2, but the rest remains far longer – I don’t know all the details myself as to why this is the case, but I know that ocean uptake is complicated by chemistry (it’s not just a simple matter of dissolving a gas in a liquid – because there’s also CO3-2 and HCO3-1 ions and Ca+2, etc…), and the time it takes for the upper ocean to exchange mass with the deep ocean, and while there is a CO2-fertilization effect, trees don’t just grow twice as tall in response to a CO2 doubling, do they? (well, it’s more complicated than that…) … and there’s respiration and decomposition…etc….
Because the C is coming from fossil fuels, the total amount of C in the combined atmosphere+vegetation+soil+upper ocean+deep ocean must be increasing. Except over longer time periods, during which some organic carbon may be geologically sequestered, and some inorganic carbon is also geologically sequestered… These are generally slow processes – in the meantime climate changes affect the carbon cycle…
One for the geologists:
http://www.nature.com/ngeo/journal/v1/n8/abs/ngeo262.html
Nature Geoscience 1, 511 – 514 (2008)
Published online: 20 July 2008 | doi:10.1038/ngeo262
Subject Categories: Atmospheric science | Climate science | Hydrology, hydrogeology and limnology
Increase in hourly precipitation extremes beyond expectations from temperature changes
Geert Lenderink & Erik van Meijgaard
Patrick-027 wrote:
> … In contrast, CO2 takes a few years to come out of the atmosphere ….
Longer, actually.
Try the Search box at the top of the page, or the “Start Here” links also at the top of the page, or use the Science Links sources on the right side of the page.
David Archer’s link for example, under Contributors.
His Publications link has the numbers you were trying to remember:
Millennial Atmospheric Lifetime of Anthropogenic CO2
” ….. Many slowly-responding components of the climate system, such as ice sheets, deep ocean temperature, permafrost, and methane hydrates, will be sensitive to the long tail of the CO2 climate impact. Most of the CO2 drawdown will take place on time scales of centuries, as CO2 invades the ocean, but it is too simplistic to call the invasion timescale the atmospheric lifetime of the CO2, as is commonly done in popular and scientific discussion. We argue that a better shorthand for the lifetime of anthropogenic CO2 would be “hundreds of years plus a significant fraction that changes climate forever”. …”
http://www.pik-potsdam.de/~victor/archer.subm.clim.change.pdf
See his link, right side of page, under Contributors, for more and better information.
Yes
Re 191 – thanks, but I wasn’t actually saying that the CO2 perturbation ends in a fews – I was starting with the bit that Boris knew (the residence time of a CO2 molecule) and building off of that to explain the difference between residence time and perturbation longevity.
I’ve read through all of the comments, and no-one replied to this one – as everyone was too busy disagreeing with Boris (I was hoping for either hard facts or a refutation :)) Apologies if I missed it:
#119I think the data suggests that the Thermhaline Circulation may be much more vulnerable than some have suggested, as there is evidence of considerable fluctuations in the flow on decadal time scales. I have seen evidence which suggests that the THC may have weakened (or even shutdown) in the Greenland Sea THIS YEAR, but I have no direct oceanographic measurements to support that view
What evidence do you have for that statement, Eric Swanson? It’s a little dramatic, isn’t it? I thought the ‘Day After Tomorrow’ scenario had been discounted by climatologists as being not very probable?
Re 194 – I don’t know enough about the current condition or vulnerability of the Thermohaline circulation to comment on 119, but about “The Day After Tomorrow” scenario – it wouldn’t happen that fast, it wouldn’t happen in that way, and it wouldn’t be that big. None of which necessarily precludes the suggestion of 119.
It wouldn’t happen that fast – there is the thermal inertia of the oceans. Regionally a fast change (but how fast?) can occur as surely as a Chinook wind (although that’s over land, and it’s a weather event, not something that lasts 100+ years), by rearranging hot and cold, etc, … fast climate changes in as far as average temperature changes may also occur regionally but not so easily globally or hemispherically (depending on what one considers ‘fast’ of course). Circulation patterns are another matter – NAO, ENSO, QBO… – of course those examples are recurring fluctuations that can be part of a longer timescale stable climate…
Also, intense precipitation can only occur on small space and/or time scales – otherwise it is limited by the global evaporation rate. Granted, an inch of water is 10 inches of snow, give or take, but still…
It wouldn’t happen that way – well, the one point I’ll make is that when cold stratospheric air ‘plunges to the surface’, it heats up. It heats up so much that it is hard for it to plunge to the surface, very hard (it’s the adiabatic temperature change that occurs with changing pressure, and it’s why the temperature can decrease with height (as is typical in the troposphere) up to some rate without being unstable). The only way around this is to have the surface pressure in the centers of those three storms very very very very very very very low (you may need an oxygen tank?), to a point that would make Hurricane Wilma look like a weak wave in the easterlies. I can’t see how AGW or most other climate changes would cause such a storm … maybe if two large asteroids coming in nearly horizontally from opposite directions could stir up something?
It wouldn’t be that big – I think the biggest cooling impact would be in the North Atlantic and surrounding areas, and Europe in particular since it tends to be downwind.
Also, we are starting from a warmer point than the Younger Dryas, which was a cold snap (at least in Europe, not sure about the global extent off hand) imbedded in the overall deglaciation process, thought to have been caused by fresh water from melting ice pouring into the Atlantic. I think there was still significant ice mass in Canada at that point. (PS this is speculation at least on my part, but when you start with large ice sheets, you can get meltwater lakes, which, depending on geography, might get large, and if they’re ice-dammed, and the dam breaks, you can get very rapid changes. Such catastrophic flooding occured in the Northwest U.S. several times at least.
Why this negative attitude about geologists? How can you demand that we should respect your expertice when you don’t respect our? Geology provides the solid base for many of your fancy models. We are out in the field, doing the hard and dirty (and very intresting) work which provides you with knowledge about past climates. Without its history, climate science is blind. I suggest that you read the Paleoclimate chapter in AR4, most of it is pure geology and it is fundamental for the understanding of climate. Those of you who haven’t should also read David R. Hickey’s comments in this tread [83] and [113].
Re 196 – I respect geologists’ expertise.
Geologist, #196, one issue: Geologist have been putting themselves up as experts in the field when it comes to climate. Where they are not, surely some umbrage is deserved if not warranted for this?
Past climates didn’t have dinos digging up a trillion barrels of oil. This changes things somewhat.
‘K?
Tracy, “Boris (I was hoping for either hard facts or a refutation :))”
Well Boris would have had to have said something sensible first.
If someone asked you “Does the price of teal feathers go up when corn meal supplies are falling?” would not your first query be “what?”. Maybe followed by “Why are you asking me?” then maybe “And what’s that got to do with anything?”?
Boris started with “CO2 is caused by temperature increases.” What hard facts are needed that aren’t in the intro for this site? It’s arrant nonsense! And it really isn’t worth any more “hard facts” to refute than “you’re wrong” or “why is that?” (to which you will notice Boris just said “I give up, I wasn’t expecting zealotry against me, you nuts” rather than explain why he’s right or how his “theory” [in the WAG sense of the word] works).
So maybe I could ask you: what query or point were you expecting hard facts for? Don’t “hand-wave” complaints, if you’ve got a complaint, let it be known!
Well we are the experts about palaeoclimate (including most of Holocene). Yes, there are sceptical geologists and yes, there are geologists who claim that they are experts in areas that are actually outside their expertise but if you can’t acknowledge geologists for finding the proxies which you use for testing your models, or for telling you what range of climate change is natural or finding geological analogies to the present warming, how can you blame those geologists who don’t acknowledge your models?