I was really impressed by this picture when I first saw it. It is from the NASA website and shows the extent of warming in the Arctic relative to the rest of the globe.
An American newspaper included comment that:
A University of Alabama scientist says global warming is not nearly as global as some people think. …Temperatures in 2005 followed a general pattern seen since 1978, with the most significant warming seen in the northernmost third of the planet. Large regions of slightly warmer than normal temperatures covered much of the globe.
The Arctic atmosphere, however, has warmed more than seven times faster than that over the southern two-thirds of the globe.
And there was comment at Tim Blair’s popular blog along the lines:
The carbon dioxide from fossil fuels is distributed pretty evenly around the globe and not concentrated in the Arctic, so it doesn’t look like we can blame greenhouse gases for the overwhelming bulk of the Northern Hemisphere warming over the past 27 years
Vincent Gray has written that:
The models predict increased warming, equally, at both the North and South Poles. The measurements show that the two poles are completely different. The North Pole is warming the South Pole is cooling.
The models predict much greater warming than is observed, and the only way they can get out of it is to assume a large cooling influence of clouds and aerosols, Since these are concentrated in the Northern Hemisphere, there should be greater net warming in the South than in the North. The observations show the opposite.
But, according to Cecilia Bitz writing for Real Climate the models can, and do, account for lots of warming at the Arctic and not much at the Antarctic:
Manabe and Stouffer (1980) first popularized the phrase “polar amplification” to describe the amplified rate of surface warming at the poles compared to the rest of the globe in their climate model’s response to increasing greenhouse gas levels.
Their early climate model had a simple ocean component that only represented the mixed layer of the water. Their model had roughly symmetric poleward amplification in the two hemispheres, except over the Antarctic continent, where they argued the ice is too thick and cold to melt back.
…Observed polar climate change from the instrumental record is not symmetric. Except along the Antarctic Peninsula , most evidence of significant warming is from the Arctic. In addition, total sea ice extent in the Southern Ocean has had no significant trend since satellites began taking data in 1979 (Cavalieri et al 2003). Newer climate models generally also have very modest or no polar amplification over the Southern Ocean and Antarctica in hindcasts of the last century. The presence of a deep and circulating ocean component is key because ocean heat uptake increases most in the Southern Ocean as the climate warms (see Gregory 2000). The asymmetry at the poles does not however result from a difference in feedback strength associated with the ice or atmosphere. In fact, when these same climate models are run to equilibrium (in the same way that Manabe and Stouffer ran their model so that ocean heat uptake is not a factor) the hemispheres have nearly equal polar amplification.
David Jones at the Australian Bureau of Meterology explains:
The failure of the Antarctic to warm is pretty well understood. It is linked to the marked strengthening which has occurred in the southern annular mode. The “southern annular mode” is a fancy name for the strength of the Antarctic low pressure trough and westerly winds (the roaring forties, furious fifties, screaming sixties).
… Over the last 30 years we have seen a very marked intensification of the trough – most of this happened in a short period of time from around 1970 to 1990. This is believed to be due to the loss of ozone in the polar stratosphere which caused a very strong cooling of the stratosphere and upper troposphere over the Antarctic. This cooling lead to a strong increase in the temperature gradient between the equator and poles, which through the dynamics must strengthen the westerly winds (this is summarised in a fairly basic dynamical equation called the “thermal wind” relationship).
The strengthened westerlies has a number of effects. These include enhanced warming on the northern side of the trough (the trough typically being near 65S). This explains the spectacular warming over the Antarctic Peninsula (which is occurring much faster than one might expect from the simple greenhouse effect). On the southern side, the reverse happens; i.e. cooling.
For the last 20 years of so, this cooling has been sufficient to offset the enhanced greenhouse effect. This is a great example of the thermodynamics (temperature changes) and dynamics (winds etc) operating in different directions. Another effect of the stronger westerlies is that the increase the equatorwards drift of sea ice (through a process called Ekman drift) which probably explains why sea ice in the southern hemisphere appears to have retreated extensively from around 1900 to 1970 and stabilised and infact expanded subsequently.
There is a real cautionary tale here about non-linearities in climate change.
There is, in my view, also a real cautionary tale in the new paper by Keppler et al. in science journal Nature as summarized in the Editorial:
The unexpectedly high levels of the green-house gas methane over tropical forests, and the recent decline in the atmospheric growth rate of methane concentrations, cannot be readily explained with the accepted global methane budget. Now a genuinely surprising discovery provides a possible explanation for these phenomena, and may have implications for modelling past and future climates. It was thought that methane formed naturally only in anaerobic conditions, in marshes for instance. In fact living plants, as well as plant litter, emit methane to the atmosphere under oxic conditions. This additional source of methane could account for 10-30 percent of the annual methane source strength and has been overlooked in previous studies.
Vincent Gray has remarked with respect to this new finding that:
The answer to the fact that climate models cannot simulate actual global temperature change may be due to a fact I have been emphasizing for many years. The models all assume that greenhouse gases are “well-mixed”, however, they are not “well-mixed”, so that temperatures cannot be adequately calculated by using average greenhouse gas concentrations. You should use actual concentrations over the particular region.
… Of course, average methane concentrations in the atmosphere have apparently stabilised, so this present scare does not add any extra greenhouse gases to the atmosphere. It does cast into serious doubt current models supposedly relating emissions of methane to atmospheric concentrations, though.
This discovery will certainly change attitudes to “climate change”, for it now appears that in order to reduce “global warming” you should not only cut carbon dioxide emissions, but you should also cut down forests, reduce agriculture, drain wetlands and cover the world with concrete.
Rather than “cover the world with concrete” as concrete is also a source of greenhouse gases, there is perhaps reason at this time in our history for both global warming skeptics and global warming believers to be a bit humble. There is so much we just don’t understand.
But someone, tell me how important is it really, as Vincent suggests, that we “use actual concentrations over the particular region”?
Jennifer Marohasy BSc PhD is a critical thinker with expertise in the scientific method.
I don’t know enough about it to say for sure, but i would be interested whether vincent was referring to average global temp or temps by region when he comments ‘….the fact that climate models cannot simulate actual global temperature change’.
From what i understand from the IPCC publications, models can accurately duplicate the way that global average temp has changed over the last 100 odd years, but only by taking into account the influence of the human contribution to greenhous gases.
Was Vincent talking about region-specific warming, which i would guess is trickier to model?
“.. .. .. but you should also cut down forests, reduce agriculture, drain wetlands and cover the world with concrete.”
Early days, and very interesting. But let’s get some independent confirmation of the magnitude and generality of the plant methane effect. And if it is as stated I don’t think we’ll be carrying out the actions as above. It will still come down to reducing humanity’s CO2 emissions (or not).
What’s the reference or study to say the GHG gases used by the models are not “well mixed”.
It seems that the Arctic cooled more in previous years,
http://data.giss.nasa.gov/cgi-bin/gistemp/do_nmap.py?year_last=2005&month_last=06&sat=4&sst=1&type=anoms&mean_gen=0112&year1=1965&year2=1975&base1=1937&base2=1946&radius=1200&nobanner=0
I prefer the mollweide projection, less distortion
http://upload.wikimedia.org/wikipedia/en/2/29/Global_Cooling_Map.png
Can I ask a silly question?
Could it simply be that much of the Antarctic ice mass sits above the water?
I can imagine the southern ice sheet is mostly out of harms way for the time being.
If the issue you’re worried about is sea level.
It should also be noted that the above map projection grossly distorts the scale of the arctic warming by giving the impression that it is of a similar band at the equator. Lets see the same data on a scale adjusted projection, and then tell the Eurospivs to get on with it as it is obviously not our problem.
Undistorted map of mean temps
http://upload.wikimedia.org/wikipedia/en/8/8c/Global_Warming_Map.jpg
“not our problem” .. .. hmmm
Eurospiv = I didn’t like what they did with Kyoto – so there.
Meanwhile back at the actual point .. ..
John Christy and others are basically pointing to the fact that the observed mean temperatures contradict the predictions of the GCM’s.
Hence the models are in error, which is hardly surprising since climate cannot be modelled in the first place.
Global warming is global not just at the Artic.
Hence GW theory is falsified, again.
And Christy is still smarting from not being able to sort out his MSU data – come on !
Louis “John Christy and others are basically pointing to the fact that the observed mean temperatures contradict the predictions of the GCM’s.”
The GCMs predictions are pretty well in line with the observed mean temperatures. Where is you reference to the contrary.
“Hence the models are in error, which is hardly surprising since climate cannot be modelled in the first place.”
Obviously all the scientists are just playing computer games.
“Global warming is global not just at the Artic.”
So you believe in global warming now.
“Hence GW theory is falsified, again.”
But you just said global warming is global.
>The answer to the fact that climate models cannot simulate actual global temperature change may be due to a fact I have been emphasizing for many years.
This statment is counter factual. The important greenhouse gases are very well mixed in the troposphere. Models do broadly simulate the distribution of temperature change when they include greenhouse gases, aersols, ozone, solar variability, and volcanism. They do not when you include greenhouse gases only; this is hardly suprising as greenhouse gases lay down the broad pattern of warming, but the local details are often laid down by the lesser forcing agents.
I am suprised that the various statments being made attacking the mainstream science are not backed up by reference to any studies which compare modern climate model simulations with observed warming patterns. Such studies do exist… Surely, the overturning of a 100+ year old theory requires some evidence?
David
Ender,
Christy’s data shows no global warming only isolated regional warming. Hence global warming based on observation is falsified.
David,
climate cannot be modelled because non-linear chaotic systems are impossible to model.
Your quote of one of my sentences out of context and then waffling onto mixing greenhouses which is not mentioned in that sentence leaves me……
Louis – I cannot believe you have not taken the time to read the reference in Jen’s lead. The whole point is that are quite good reasons why the regional warming is showing and that Antarctica is so far behaving differently.
You are comparing a puff piece written for newspapers with a more scientific article including model results, analysis and detailed references. Christy is simply winging it and like with the tropospheric warming MSU data – he has come unstuck (again).
Your comment about chaos is simply incorrect. I bet you next winter will be colder than this summer and the one after that and after that. We do know somethings. The tide levels and timings are inherently predictable but the exact water height and wave action at any time is not ncessarily so. In any case the GCM models exhibit chaos themselves in representing the many non-linear chaotic processes and so the GCM models are run a numbe rof times 10 to 50 times to sample that chaotic variation. A completely unstable system is thus identifiable. So confusing the chaos of daily weather is not valid to hold with climate. This is an OLD contrarian argument that gets recycled.
I have presented a range of material on Warwick’s blog for you in suitable threads on this issue and you have chosen to not answer any of my responses and questions posed to your questions. You have abdicated your position and walked away.
Thank you Roq, for both maps, a much closer representation of the truth. The other point of reference is relevance to the scale of variation in temps and, perhaps, to the scale of variation in temps on the moon, with no atmosphere. This would highlight the dominant role of water vapour in planetary warming.
What the mollweide projection on warming shows is a slight warming of places like the Gobi desert which have a wide temperature range and an essentially irrelevant change in places with a smaller temperature range.
Louis – “Christy’s data shows no global warming only isolated regional warming. Hence global warming based on observation is falsified.”
So is this isolated regional warming is taking place over the whole globe? So if you put all the regions together and include the oceans which are also warming – guess what – it is global after all!!!
Is anyone arguing about the extent of the warming or the differential nature of it. What a diversion. And Aussie warming too – how about that?
P.S. The water vapour line is another old recycled contrarian argument. Just like the atmospheric water itself 🙂
Louis – “climate cannot be modelled because non-linear chaotic systems are impossible to model.”
No they are not. They are impossible to predict exactly. No GCM attempts to predict exactly what the climate will be however even chaotic systems can be modelled to a degree of precision dependant on the computer power available. The faster the computer the smaller the cells and the more variables that can be taken into account with the simulaton taking a reasonable time.
If you are trying to say that it is impossible then you would have to say modelling a star’s interior or the airflow over an aircraft’s wing is impossible.
The chaos argument is interesting. But if you don’t understand the nature of what is being simulated to answer what point – you can easily run a specious argument. The real atmosphere displays chaotic behaviour at times – so does the mathematics and physics inherent within the climate models. An ensemble of runs is made – not just one run. The starting conditions for each run are very slightly altered to induce the possible chaotic aspects.
The other aspect that normally gets run here is one of scenarios versus predictions. Why don’t they make predictions like with weather. Simply we don’t know what humanity will do or not do about greenhouse gases. So you can only have scenarios or conditional predictions.
Ender and Phil Done
Both of you are silly – if your don’t understand the the thing you are studying, then there is no way, ever, that you could model it.
To model something is to understand it.
Neither of you do.
Now go and get a real job.
Very simple Jen,
Vincent Greys’ explanation is one view but for others, as said by Christy, “we don’t know”.
Work it out.
Ian Mott mentions the GIS projection of the map Jen reproduced above.
It is actually a fiction.
Ender and filly Philly might explain?
Louis – “Both of you are silly – if your don’t understand the the thing you are studying, then there is no way, ever, that you could model it.”
So can you tell me the precise way that airflow travels over an aircraft’s wing including the boundary layer and the transition from laminar to turbulent flow? Aerodynamicists have no real knowledge of the boundary layer and have to use emperical methods to ensure that the transition does not affect normal flight. Are you trying to say that this can not be modelled even though it is not properly understood?
oooooo – appeal to authority – it’s Vincent Gray not Grey too. Pity he’s wrong. Try appealing to logic.
What has the map projection got to do with price of eggs in China. What’s your point?
Given Louis told me I’m silly I’m wearing a party hat and blowing one of those party streamers while writing. The kids tell me I look very silly.
And Louis – you’d like my Mum – she’s always telling me to get a proper job.
“climate cannot be modelled because non-linear chaotic systems are impossible to model.”
Chaos does not prevent you from determing the climate attractor, it only prevents you from determing which trajectory you are on in the attractor. The difference is subtle but very very important. Now that is sorted, prehaps we can put this source of confusion to rest?
There are 100s of studies which demonstrate climate change predictability. I am yet to see a paper by a atmospheric modeller which demonstrates that it is not possible.
The seasons are the most obvious example of a changed climate attractor… you can be very very very very certain that the increased solar radiation you recieve in January will make you warmer than July, even if you can’t be sure what the temperature will be on January 1, 2, 3,…. The enhanced greenhouse effect is exactly the same. Add a few extra watts at the surface and it will warm… no ifs and no buts.
David
David – “prehaps we can put this source of confusion to rest”
Louis will continue to bring it up for the next 50 years until he wears us down. We have made some progress – at least he does not think the greenhouse effect means that there is a sheet of glass over the Earth. This took a couple of years.
Ender, David and Done,
Make everyone happy – go find a scientific paper with a predictive model for turbulence, whether hyraulic or gaseous.
Or come up with a formula to predict it – all three of you will get a Nobel Prize for it – guaranteed.
As for the issue of the transition from laminar to turbulent flow, models mean input A produces out B.
David go find a mathematical model of turbulence which does that explicitly. You will get another Nobel for it.
Mars has a thin atmosphere, 95% CO2 and is cold, Venus has an atmosphere that while gaseous has the physical properties of a liquid (due to its internally high temperature) and is also mainly CO2.
Yet poor old earth with 0.04% CO2 is deemed to go into runaway greenhouse when it gets to 0.05% CO2.
So might there be any differences between Mars and the Earth – Louis (atmospherically – broadly speaking – what do we know)
And Louis – you don’t have to predict turbulence – but you can sample it’s distribution – alas again you have missed the point.
Of course in true fashion we will get to a point where Louis will do a runner or not answer any questions.
Ender,
where is my reference to the contrary? – why the very reference I quoted – Christy. op. cit.
Louis: Lovelock’s work is consistent with your claim that CO2 % alone can’t explain the greenhouse effect. Lovelock worked in the 60’s on methods to detect life on other planets. At NASA, considering the sterile conditions on Mars lead him to realise that the atmospheric composition of earth and its >>state of chemical disequilibrium<< was a self-regulating system that supported life.
The early use of the word biosphere included the earth’s crust as a transformer of cosmic radiation into effective terrestrial energy. Lovelock’s work is consistent with the views you put forward, you should give him a read!
>Make everyone happy – go find a scientific paper with a predictive model for turbulence, whether hyraulic or gaseous.
There is no need to explicitely predict all scales to get accurate physical predictions. This is the very basis of almost all physical predictions. Your argument is as dis-ingenous as suggesting the progression of the seasons is impossible to predict.
One might hope for a more substantial strawman argument?
David
Just when Louis thought it was safe to go back in the surf (play Jaws theme music now!) – RC has a go at a Bob Carter argument on greenhouse forcing
http://www.realclimate.org/index.php?p=220
Think they’re declaring “open season” on contrarians. Can contrarians be sustainably harvested. Are there distinct contrarian genetic populations that need separate management. Should Greenpeace blockade RC to preserve the species?
Louis – “where is my reference to the contrary? – why the very reference I quoted – Christy. op. cit.”
You cited a newspaper report that quoted Christy. There was no data or link to data supporting the statements that amplified arctic warming has not been modelled by the GCMs.