Guest commentary from Spencer Weart, science historian
Despite the recent announcement that the discharge from some Antarctic glaciers is accelerating, we often hear people remarking that parts of Antarctica are getting colder, and indeed the ice pack in the Southern Ocean around Antarctica has actually been getting bigger. Doesn’t this contradict the calculations that greenhouse gases are warming the globe? Not at all, because a cold Antarctica is just what calculations predict… and have predicted for the past quarter century.
It’s not just that Antarctica is covered with a gazillion tons of ice, although that certainly helps keep it cold. The ocean also plays a role, which is doubly important because of the way it has delayed the world’s recognition of global warming.
When the first rudimentary models of climate change were developed in the early 1970s, some modelers pointed out that as the increase of greenhouse gases added heat to the atmosphere, much of the energy would be absorbed into the upper layer of the oceans. While the water was warming up, the world’s perception of climate change would be delayed. Up to this point most calculations had started with a doubled CO2 level and figured out how the world’s temperature would look in equilibrium. But in the real world, when the rising level of gas reached that point the system would still be a long way from equilibrium. “We may not be given a warning until the CO2 loading is such that an appreciable climate change is inevitable,” a National Academy of Sciences panel warned in 1979.(1)
Modelers took a closer look and noticed some complications. As greenhouse gases increase, the heat seeps gradually deeper and deeper into the oceans. But when larger volumes of water are brought into play, they bring a larger heat capacity. Thus as the years passed, the atmospheric warming would increasingly lag behind what would happen if there were no oceans. In 1980 a New York University group reported that “the influence of deep sea thermal storage could delay the full value of temperature increment predicted by equilibrium models by 10 to 20 years” just between 1980 and 2000 A.D. (2)
The delay would not be the same everywhere. After all, the Southern Hemisphere is mostly ocean, whereas land occupies a good part of the Northern Hemisphere. A model constructed by Stephen Schneider and Thompson, highly simplified in modern terms but sophisticated for its time, suggested that the Southern Hemisphere would experience delays decades longer than the Northern. Schneider and Thompson warned that if people compared observations with what would be expected from a simple equilibrium model, “we may still be misled… in the decade A.D. 2000-2010.” (3)
The pioneer climate modelers Kirk Bryan and Syukuro Manabe took up the question with a more detailed model that revealed an additional effect. In the Southern Ocean around Antarctica the mixing of water went deeper than in Northern waters, so more volumes of water were brought into play earlier. In their model, around Antarctica “there is no warming at the sea surface, and even a slight cooling over the 50-year duration of the experiment.” (4) In the twenty years since, computer models have improved by orders of magnitude, but they continue to show that Antarctica cannot be expected to warm up very significantly until long after the rest of the world’s climate is radically changed.
Bottom line: A cold Antarctica and Southern Ocean do not contradict our models of global warming. For a long time the models have predicted just that.
(1) National Academy of Sciences, Climate Research Board (1979). Carbon Dioxide and Climate: A Scientific Assessment (Jule Charney, Chair). Washington, DC: National Academy of Sciences.
(2) Martin I. Hoffert, et al. (1980) J. Geophysical Research 85: 6667-6679.
(3) Stephen H. Schneider and S.L. Thompson (1981) J. Geophysical Research 86: 3135-3147.
(4) Kirk Bryan et al. (1988). J. Physical Oceanography 18: 851-67. For the story overall see Syukuro Manabe and Ronald J. Stouffer (2007) Journal of the Meteorological Society of Japan 85B: 385-403.
DeWitt Payne (#247) wrote:
Actually you wrote in 229:
… and polar amplification generally refers to the amplification of trends in temperature anomaly due to forcing as it is amplified by a variety of feedbacks within the climate system:
DeWitt Payne (#247) continues:
Sounds like your argument is with Professor Curry rather than the “conventional idea.” As such it sounds much less “revolutionary” than a denial of the polar amplification of trends in temperature anomaly. But I would be mildly interested in the question of whether the forcing due to carbon dioxide plus the radiative feedback due to water vapor is greater in the tropics or the higher latitudes, that is, holding albedo constant and all.
Re: #249
The height of the tropopause at the equator is about 11 miles at the equator and 5 miles at the poles. Did you you mean to say that the tropopause at the equator is lower than at poles?
Off Topic:
Still looking forward to an analysis of the different ways that Hadleu and GISS arrive at their average temperatures.
Thanks in advance.
#237 Ray: How does this answer my question? If all you point to are other recent discussions which reference the earlier “correct” studies, that gives me no idea as to how many of those early studies were wrong. Are you claiming they were all right? I would tend to view the validity of such a claim as akin to those of third world dictators who claim they received 99% of the vote.
I don’t think you really understand what I have written, and are immediately jumping to conclusions and engaging in ad hominem. The snark about “educate yourself” is perplexing. Do you consider annoying the person you are addressing to be the most effective means of persuasion, or do you just assume I am unable to be convinced, and you might get in some digs as much as you can to recover your alpha-male supremacy? Relax. Eat a banana.
I am not saying AGW is wrong. I am saying the “yeah, we knew that” assertion in the title of this post is not supported by the evidence presented. It would have been more honest, and less swaggering, to say “yes, this is in agreement with many early and most current climate models.”
I understand the impulse to overstate one’s case when one is fighting a battle for public perceptions but, it is unwise to back oneself into a corner when it is not necessary.
Harold Pierce Jr (#252) wrote:
Not sure what I meant — but I appreciate the correction. (Long week.)
Re #251 Timothy: I am also mildly interested in 1) DeWitt Payne’s result (magnitude of the effect?) and in 2) a conceptual and quantitative accounting of the temperature polar/high latitude amplification effect — on both hemispheres. I’m pretty sure water vapour plays a role as it does for the altitude amplification — but seeing numbers would be nice.
It may be true that the models handle this implicitly, but like DeWitt Payne points out, this implicitness is a PR handicap. It would be useful to see the contributions split out, something to refer to. Has anybody done this?
Re:244 Alastair, what you say seems to make sense, however I do not understand why a melting artic causes significantly higher water vapour, the air temp especially under 5000ft is still very cold, couple of degrees C, that would not produce much evaporation in my opinion, unles you refer to the rapid movement of melt water as it carves channels and moulins causing spray. Maybe more of the damage is being done from the bottom up due to a warmer artic ocean than forcing due to water vapour..please correct me if I’m wrong!
Related to the topic of Antarctic cooling, Patrick Michaels reports on a 2008 paper by Chylek and Lohmann which calculates climate sensitivity using Vostok ice core data for the last 42,000 years. Here is the abstract:
Essentially they are saying that aerosols are relatively more important, so carbon dioxide has less effect than we thought. I have a hard time with a low end climate sensitivity of 1.3 K when the raw forcing is 1.2 K. That implies no water vapor feedback at all.
Any comments?
Re:245 Chuck Booth. It is true that an elevated level of CO2 does promote more vigorous growth in most plants but only to an extent. CO2 uptake by plants depends on the level of availible nitrous compounds in the soil. In poor soils with very little nitrogen, plants do not benefit by an increase of CO2 of if they do..only negligibly.
Back to #229 DeWitt Payne:
I may be kicking in an open door here. In your calculations, did you just double CO2 (and CH4) for calculating the forcing of tropical and high-latitude atmospheric columns, respectively? Or did you also take into account that the surface temperature will increase, which will increase H20? And if so, in which way? (I assume you used http://geosci.uchicago.edu/~archer/cgimodels/radiation.html … BTW the temperature/water vapour block of the interface looks a bit mysterious to me. Is there a help file somewhere?)
I ask because Prof Curry’s reply quoted by you (in #247) in her third item appears to be based on doing this. So: did you?
Reid, if you had taken the time to read the studies, or even tne posts about them, what you should have taken away is that if you get the physics right–in this case, a realistic ocean circulation model–then Antartica lags behind in warming and may even cool. This is not a case of a model getting lucky, but getting the physics right.
If the southern ocean is asborbing the added heat that is allowing Antarctica to cool over the past 20 odd years, wouldn’t that lead to less sea ice? But sea ice in Antarctica is a record levels. Can someone explain?
Re # 259 Lawrence Coleman: “CO2 uptake by plants depends on the level of availible nitrous compounds in the soil…”
An important point, which I alluded to when I wrote (#245):
“And then there is the not-so-minor problem of where those C4 and/or C3 plants will get the additional nitrogen and phosphorus need to sustain their elevated growth in a warmer, CO2-rich climate,…”
Dr. Weart,
You wrote,”As greenhouse gases increase, the heat seeps gradually deeper and deeper into the oceans. But when larger volumes of water are brought into play, they bring a larger heat capacity.”
I am having trouble getting my head around this idea of “heat seeping lower.” I googled a few references and tried to read some articles mostly by an oeanographer named Wunch. A little to technical for me but from some of the introductory passages I got these general concepts.
1. The tropics have high rain and high precipitation which would make less dense water. The tropical circulation transports Petawatts of heat to the poles. So I would think both polar oceans should warm with increased CO2. And because that warm water is less dense it should stay on the surface and warn Antarctica like it does the Arctic even if it is to a lesser degree.
2. Light energy (in the tropics) penetrates to about 100 m but infrared cooling is limited to the surface due to the limited penetration if infrared rays in water. That suggests that you might get a gradient of warm below the surface and cooler at the surface and cause the warm water to rise. And again the cooling at the surface should contribute to warming of the south pole. But also the reflected infrared from the CO2 shouldn’t penetrate below the surface. So I don’t see a seeping mechanism.
Your point also makes me ponder other questions, assuming that there is some general mechanism I don’t see or understand. If there is a way for warm water to seep or sink lower and be trapped there, allowing Antarctica to cool, then when does that heat get released into the atmosphere? It seems that this point is taken as a reason to be concerned for more added future warming. But if true, then couldn’t some of the warming experienced now be the result of heat released from the ocean that was stored at some earlier time in history?
Does new acoustic measurements show pockets of “ancient ocean heat? I thank you for considering my lengthy questions.
#259 Lawrence
Yes, that’s an instance of Liebig’s Law of the Minimum that I mentioned before. {Soil/nutrients, water, sun, climate}.
No amount of CO2 will let you grow corn in the Sahara.
As it warms, you might think that Northern Canada would replace the US cornbelt, but the soil isn’t the same, and the solar insolation isn’t either.
Some species need some cold … which is why sugar maples are moving North, much to Vermont/NH’s displeasure.
Re #257 Lawrence,
I am not sure why you are mentioning the air temperature at 5000 feet. The Arctic sea ice is an altitude of approximately 0 feet, unlike the East Antarctic where much of the snow and ice is at a high elevation.
We know that the Arctic summer sun is strong enough to melt about 3 feet of ice each summer (which reforms during the winter.) The heat needed to do that is enough to raise the temperature of open water 3 feet deep by nearly 10 C. Without the sea ice, typically covered with fresh snow and so with a high albedo reflecting the solar flux away, the dark open water will absorb that solar flux and float on the ocean surface because it is less dense. Thus the surface of the Arctic Ocean which produces the atmospheric water vapour will warm disproportionately.
It is a little bit like Murphy’s Law where everything conspires to make it worse.
Cheers, Alastair.
Re: 267 Alastair, I had a think about that last night and you’re right. The higher concentrations of water vapour would then ultimately cause more snow especially during the artic summer which would be as useless as a solar powered torch if he water temp is hovering just above freezing. Where is the majority of that snow deposited- on the ice sheet or open ocean? Do you also have data what the vapour contentrations are during the artic winter. Logic says that the warmer seas would produce more steam and increase the snowfall during winter as well. That’s also what a recent antartic expedition found, studying a ‘canary in a coalmine’ glacier..that the annual snowfall was well above average for the past 30 years and yet the glacier is travelling much quicker than before. The increase in antartic ocean temps seems to promote more snowfall.
In 266 John writes “Some species need some cold … which is why sugar maples are moving North, much to Vermont/NH’s displeasure”. One has to be careful. Sugar maple trees grow all over the place. However, they only produce maple syrup in a very limited area. It will not be the trees moving north, (if AGW is real), but the weather/climate that makes the trees produce maple syrup.
Gusbob, what’s your source for believing what you write about sea ice being at record levels in Antarctica? Do you know how to look it up?
Hank,
The record Antarctic sea ice levels came from a graph from the National Snow and Ice Data Center.
http://nsidc.org/data/seaice_index/s_plot.html
I don’t remember if they called it a record or not but several titles from a google search mentioned record Antarctic sea ice level, so I assumed between those claims and the graph it was a valid observation.
Why do you ask? Is there something wrong with their data?
Re #260: so I did the calculations myself. Doubled CO2 and CH4, and tuned up the temperature offset until getting the same outgoing radiation back. Result:
Rel. tropics __ subarctic
hum. ________ summer winter
---------------------------------
100% +1.85°C +1.32°C +0.94°C
_50% +1.74°C +1.31°C +0.91°C
__0% +1.45°C +1.11°C +0.78°C
---------------------------------
All this under no cloud cover or rain.
And the caveat by Dave Archer, the author of the web model, that it is outdated, though I don’t think that has any bearing on these results.
But, it seems to be true: purely radiatively there is tropical, not polar amplification.
Re #265:
Yes, Carl Wunsch. Knows more about ocean currents than all of us amongst ourselves have ever forgotten… The “seeping lower” is a reality. It is due to mixing of surface and deeper waters, and the global circulation is what is causing it.
It is true that warm water wants to stay on top. That’s why in the tropics the surface waters are some 27°C, and at depth only 5°C. This is a robust situation and the basis of, e.g., OTEC power generation.
However, as the water flows to higher latitudes (north or south), it cools down. Also, remember that the density contrast between warm and cold water isn’t all that big, contrary to the situation in air. That’s how the global circulation manages to push warm water to depth against the gradient. And elsewhere then the same amount of cold deep water has to come up. (I probably miss something here; see https://www.realclimate.org/index.php/archives/2006/10/carl-wunsch-the-economist-and-the-gulf-stream/ for more.)
The cooling of the surface water happens mostly well before the south pole. And then, the surface water is taken down by currents, in the southern ocean well away from Antarctica.
The warm(ish) surface water that is taken down by currents, is mixed into the (huge!) volume of cold, deep ocean water, where it stays. It isn’t really “trapped”: rather, you could think of it as acting as a very large heat buffer, like the stone mass of an open hearth, the type they have in Scandinavia. Lighting a fire and heating the air in the fireplace goes quickly, but getting the body of the hearth heating takes hours or days. But then, the house will stay warm as the hearth slowly releases its stored heat also without a fire burning.
What it means climatically is that atmospheric heating is slowed down, and it takes longer to reach the state of equilibrium corresponding to current CO2 concentration (often people will say that part of the heating is still “in the pipeline” or “committed, but not yet seen”). The heat added to the deep ocean will stay there until it has a reason to come out again. That would happen, e.g., if we would cut our CO2 emissions and the atmosphere would start cooling again. Then, the heat from the deep ocean will slowly, slowly seep out again, slowing down the process of atmospheric cooling. Precisely the reverse of what we see today.
The idea that this heat is “trapped” somewhere in a secret place, waiting to jump on us suddenly when we least expect it :-) isn’t the way this works in reality.
Hmmm… no comment… do you have a reference?
…or the other way around :-)
Re: Jim Galasyn, read that article..phew! That about 210 billion cubic metres of ice/year going into our oceans from just one glacier. If that is old ice as it no doubt will be and wont contain much O2 that’s maybe 190-200 billion tonnes of water/year raising the sea level. However with increased ocean temps a lot of water is being sucked out of the oceans as well as steam (hydrologic cycle)..do scientists accurately know the nett gain in ocean volume from the output of all these glaciers? That is just one of many glaciers which are speeding towards the ocean so the figures are quite mind boggling..I’m thinking a few trillion tonnes of additional water/year maybe? Thanks for the link!
I must be missing something. Maybe 2 somethings.
The first paragraph seems to say that Antarctica is getting colder, and that’s what the models predicted. The models say southern hemispheric warming would lag northern hemispheric warming, if I understood that article. That’s different from the models predicting the southern hemisphere actually getting colder, isn’t it?
Also, I read somewhere the effects of increased atmospheric CO2 were strongest near the poles, because there is less water vapor in the the air. So even if the southern hemisphere overall isn’t showing warming, shouldn’t we expect Antarctica to show warming? Or am I misremembering the part about the water vapor?
I don’t remember reading predictions prior to this decade that Antarctica would get colder because of increased CO2, so I’m confused by this article.
Re Lawrence’s comment in 275, this is indeed sobering news.
You may be missing the word I’ve bolded below:
“Parts of Antartica getting colder” does not mean “the southern hemisphere is getting colder”. It’s not. Nor does it mean all of Antarctica is getting colder. It’s not, either.
Martin, that was a very helpful post full of answers. I’d been hoping someone who really knew something would come along, before I tried!
Martin,
Thanks for taking the time to provide your explanation about heat seeping into the ocean. However I find it odd that you would give such a fanciful twist to my comment of trapped heat. Perhaps I could have said the heat was “stored” or “mixed and unnoticed” as you did. This seems to be a merely a point of semantic preference. Likewise when I asked how and when that heat would be released in the future, that comment seems no different than your reference that “the heat is in the pipeline”. So your fanciful twist “The idea that this heat is “trapped” somewhere in a secret place, waiting to jump on us suddenly when we least expect it isn’t the way this works in reality.” feels very patronizing and uncalled for.
Your suggested mechanism that “heat will be released when it has reason”, doesn’t add much clarity. However you then suggest the heat flows due to a mechanism controlled by being in equilibrium with the atmosphere. But this seems at odds with what I can glean from Wunsch on vertical mixing.
Martin Vermeer said “The heat added to the deep ocean will stay there until it has a reason to come out again. That would happen, e.g., if we would cut our CO2 emissions and the atmosphere would start cooling again. Then, the heat from the deep ocean will slowly, slowly seep out again, slowing down the process of atmospheric cooling. Precisely the reverse of what we see today.”
Wunsch states in his paper “VERTICALMIXING, ENERGY, AND
THE GENERAL CIRCULATION OF THE OCEANS
CarlWunsch and Raffaele Ferrari
http://ocean.mit.edu/~cwunsch/papersonline/wunschferrari2004.pdf
Wunsch states, “Heating/cooling/evaporation/precipitation directly affect the ability of the wind to create potential energy, but they are only slightly involved in the energy cycle, possibly even reducing the potential energy.”
Wunsch is saying that heating of the surface makes mixing at lower levels less energetically favorable and that mixing must be driven by the wind and tides to create enough kinetic energy to overcome the potential energy barrier of warm upper layers. He mentions that his studies cast doubts on the mechanisms of the proposed thermohaline current.
Which gets back to what I am asking. If the winds and tides drive the heat to lower depths then such mixing could happen during any season and all climatic conditions. It seems logical to conclude that any oceanic heat that is in the “pipeline” could have been placed in that pipeline 5, 10 or 100’s of years ago. And waves due to tidal forces or winds could bring it to the surface at unpredictable times.
Looking for evidence of changes in ocean temperatures there is a paper by Lyman(it was discussed here), which is under some dispute due to profiling errors in the floats found in the mid Atlantic. See http://www.pmel.noaa.gov/people/lyman/Pdf/heat_2006.pdf
However accepting that profiling error. If we look at the map of changes in ocean temperatures on page 11, the data shows large areas of the southern oceans (majority ?) are cooling or not warming. That is supported by the increased sea ice that is also being observed.
So I have to question the suggestion that heat is seeping into the ocean and ask if it is truly being measured or is just conjecture to support our theory? With most of Antarctica cooling and evidence to the contrary that the southern oceans are absorbing all this missing heat, perhaps our warming theory is incomplete in this regard.
[Response: The oceans are heating over the last few decades – there is no doubt about this. This is indicative of a large scale heat imbalance in the atmosphere, and that implies that there is further warming in the pipeline. However, the heat in the ocean is not going to ‘come back out’. Any future equilibrium state with warmer temperatures will have an ocean with more heat content than before. To stabilise the atmosphere, the SST needs to warm enough to overcome the increased greenhouse effect. Since the deep ocean takes so long to warm it is effectively taking heat from the surface and preventing it reaching the new equilibrium value. Only when that falls to a negligible value can the equilibrium be achieved. – gavin]
Re: 276 Duncan. I’m not sure the southern hemisphere is getting colder, here in Australia-Perth in western australia has had more days over 37-38C than ever, that’s the hottest they have had on record, quite a few time the temp was well over 40C. Us on the east coast have had the wettest summer for decades thanks to a very persistant monsoon trough, flash flooding has become common place all along the east and when we get the odd day of sunshine it’s up to 40C and humid. I for one would definately argue that the south is cooling off.
Re #271: The Antarctic sea ice maximum has been increasing a little, but the trend is not statistically significant. That aside, I for one would be curious to know if there’s any connection to the increase in cooler, fresher water north of Antarctica discussed here (see Figure 1 and associated text).
Re #279 Hank:
He didn’t come along :-(
About the thing that I was not quite getting, the “pump” that actually makes the warm surface waters go down, from what I read this is a tricky thing. But it appears to be part of the general circulation, largely wind-driven and Earth rotation modulated. Google for “Ekman pumping”.
There seem to be a question not of delayed warming, but no warming at all. Especially so when the interior is getting colder. An ocean delayed response would have been manifest near the coast but would have little effect in the interior. Clearly, a delayed warming is not what is at hand.
It would be helpful to see SST anomalies broken down by latitude. Anyone who knows where to find such a dataset?
Re #284: I think you can do that with GISTEMP.
Hank and Martin will want to read the article I linked in #282.
Gavin wrote,”However, the heat in the ocean is not going to ‘come back out’. Any future equilibrium state with warmer temperatures will have an ocean with more heat content than before.”
Gavin perhaps I am misunderstanding these papers when Wunsch discusses heat flux in the ocean and talks about changes in heat storage. Could you please square your statement with Wunsch’s statement below?
Wunsch wrote,
“An additional source of error, not explicitly accounted
for here, is the interannual variability in ocean
heat storage. Stammer et al. (2004) noted that there can
be a decadal-average discrepancy in ocean heat flux on
the order of 0.5 PW owing to heat storage changes.
Much of this difference is presumably involved in the
interannual ocean transport fluctuations discussed by
Ganachaud (2003).”
This is from a paper titled “The Total Meridional Heat Flux and Its Oceanic and Atmospheric Partition” 2005
http://ocean.mit.edu/~cwunsch/papersonline/wunschjclim2005.pdf
[Response: Wunsch is talking about variability – and ocean heat content will indeed change with that. But that is not the same as the equilibrium response to increased forcing. – gavin]
Re #286: Steve, yes, fascinating reading. As is the reference in it to Munk & Wunsch (1998). So it seems that wind and tidal energies on the order of 1 TW each control an equator-to-poles heat flux of 2000 TW; and wind patterns changing with the climate…
Steve,
I read the link from #282 and was fascinated to see that it supports what I have been interpreting from Wunsch’s article. From their diagram
http://www.nature.com/nature/journal/v451/n7176/fig_tab/nature06590_F1.html
from it says ” Westerly winds above the ACC (also blowing out of the page) push cold, fresh surface waters away from Antarctica across the ACC (towards the blue area) and draw slightly warmer and salty water that is low in oxygen up from the interior to the surface”
That supports the idea that winds create conditions for warmth to be transported to the surface.
It also suggests an answer to a conundrum regarding the Antarctica’s peninsula Larsen Ice Shelf collapse. The peninsula has been the major hot spot for Antarctica while most of the continent has cooled in recent years. Curiously I have noticed on a map of global cooling measured from 1937- 1975 that the peninsula was also warming during that time despite global atmospheric cooling.
http://en.wikipedia.org/wiki/Image:Global_Cooling_Map.png
This suggested to me that the ice shelf collapse was to some degree independent of atmospheric temperatures and likely due to ocean currents warming the peninsula which is is precisely what is shown in your Nature article.
Re #280 gusbob:
So I read you wrong, sorry about that. BTW are you aware how widespread such misconceptions are? Some people even claim that heat put into the ocean by solar intensity variations in the early 20th century are coming out only now, suitably timed to fake a CO2 greenhouse effect. Therefore I felt this needed to be addressed up front.
But the heat rapidly loses its memory of when it was put in… it gets quickly mixed throughout the volume, at eventually a very small temperature increment. That makes your scenario sketched here rather improbable IMHO. There are no “blobs” down there to be brought up by any mechanism. Or did I again misread you?
Here in the UK the deniers mange to keep on upsetting the apple cart. In recent days they have managed to spell out how the NH is suffering its worst winter for many a year. USA/Canada, China and many others suffering very cold temperatures (especially in the Arctic apparantly which is causing large scale ice formation that is 10 to 20 cm thicker than in recent previous years.
Here in the UK we are experiencing a bit of a very unusual february and it is warmer than usual for this time of year. The contrarians have seized upon this sea ice formation and colder than average temperatures in certain local regions to complain that AGW is once again a non event which surely cannot be happenning. How can climate science keep these people down, they have politically easy opinions that people want to hear and that the media like to express al the time.
We know that it is all nonsense, a cold winter a climate change does not make but people seize upon these flaky results especially the arctic sea ice reforming to replace last years and Antarctic growing more sea ice even though glaciers are flowing faster to the sea. Some of climate change seems to be contradictory and this seems to put climate science at odds with common sense and the notion of it.
Let us hope that the IPCC in the wake of James Hansens call for 350 ppmv limit, everyone else is working on 450/550 ppmv at the present time calls for even more far reaching CO2 limits and that the deniers are denied.
I am quite worried about James Hansens recent work and talks, he speaks much like James Lovelock these days but not quite so bad I guess. Indeed I wonder why Lovelock is not listened to more. His scientific pedigree is very good, he has done good science and continues to do so ven though he speaks of the earth regulating itself in the GAIA way that scientists seem to hate (as it appears to speak of a designer or purpose that science hates – probably stems from the gallileo days) for some reason that makes no sense as Lovelock is as scientific as the rest of them but he just figures things slightly differently when it comes to the biosphere and he has not been shown to be wrong in any peer reviewed journals that I know of.
I believe that RC did a peice on his latest book, revenge of GAIA and they were a little dismissive of his ideas but as Lovelock states, the science of systemic systems and complexity is not as yet fully accepted by the majority of scientists and is a minority view even now, even though complexity has been demonstrated empirically and GAIA to, many examples have been given.
His recent royal society talk that is published on youtube makes sense in many ways and could well be as right as empirical reductionist climate science. James Hansen speaks of wet processes and rapid non linear responses much as Lovelock does regarding the GAIA system for non linearity is the language of nature and science but science has as yet failed to grasp its full impact for linear science still works in many regards.
Gavin, 280. You said the deeper colder water draws the surface heat down, wouldn’t that be more apparent in turbulent bodies of water as there is a lot of mixing going on. The converse should be an obvious thermocline in calmer waters where there is a definite temp gradient formed or where a large outflow of fresh eg. river water meets the saline ocean. As the greenhouse effect kicks in and more severe hurricanes or areas of intense low pressure are formed over the equatorial latitudes that logically will cause more heat to be drawn down to lower depths thus cooling the upper levels..this is what I do not understand?..surley that will create ‘less’ evaporation of the sea water into the atmosphere and thus regulate the size and severity of hurricanes.
Re #289 gusbob:
OK, so that’s what you’re after! Yes… looks plausible. But please remember that this is “warm” water only by Antarctic standards :-)
RE # 291
Pete, your observation of moods and reactions to headlines is similarly frustrating here in the States.
As climate conditions are increasingly affected by continuing droughts, freakish and fierce storms, a likely early and extensive Arctic ice melt back and lower water tables in the SW US, those stories will be pushed off the front page by the worsening economic plight of the middle and lower middle class families struggling to stay in their homes, pay higher costs for everything and possibly see their taxes rise to accommodate huge new costs for higher health care, social security, rebuilding our military, etc. Grim future from that standpoint alone.
I do not mean this to sound like our saving grace to keep AGW front and center, but it is a fact Chinese and Indian government officials realize their precarious futures are related to the pace of melting of the Himalayan glaciers. They do not have the internal wealth to sustain continuing climate and water availability impacts. They will eventually be pounding the table and demanding support for their de-carbonizing and survival.
The deniers can laugh up their sleeves at this colder North American winter but the hand writing is on the wall and even smug libertarians will be caught in the web of a warming climate and drying surface.
John L. McCormick
#291, Pete, as usual contrarians don’t know climate as much as tweaking information in their favour.
look at the number of leads amongst the Arctic Ocean new ice, this is the stuff of Change:
http://www.weatheroffice.gc.ca/data/satellite/hrpt_dfo_ir_100.jpg
On my website I deal a little with a lingering zone of very cold air, I call it the Cold
temperature North Pole, hanging out mainly where the old ice is, as per picture.
There is also less clouds, hence the clarity of the entire Arctic, as the sun rises cold will turn to warm in a big way if this continues….
Re #289: gusbob, there’s a very recent paper on the ice shelf break-up (Ted Scambos was one of the authors, which should make it easy to find) that’s consistent with this. Bear in mind that atmospheric warming was still a significant factor in the break-up. This is obvious from the observed surface melt on the ice shelves just prior to the break-up. The Peninsula atmospheric warming itself has been linked to a shift in the Southern Annular Mode, which in turn looks like it has to be driven by the shift in the winds discussed in the Nature article. There was another paper in the last month that talked about the biological implications of the warming water, and (these may be referenced in the Nature article) a couple of papers in the last year that found evidence for the big pulse (actually two pulses IIRC) of CO2 out of the Southern Ocean during the last deglaciation.
I don’t know what the confidence level is in all of these new results, but it does seem like a lot of the pieces of the puzzle are starting to fit together.
A small question: Could the slight increase in Antarctic sea ice maximum extent be a result of the noted increase in cooler, fresher water north of Antarctica?
A big question: If indeed winds and thus circulation will get stronger with continued warming, what are the implications for Kerry Emanuel’s idea (developed in a paper by Sriver and Huber in Nature about six months ago) that tropical cyclones will play a key role in cooling the tropics in a warmer world?
[Response: “Winds” and “circulation” are not generic or monolithic things. Therefore you can’t expect all winds or all circulations to increase or decrease together. You need to be very specific – for Antarctica, the SAM shift has increased westerly winds around the continent and this is likely due to a combination of ozone depletion and increasing CO2. But other circulations may well weaken (for instance the Hadley or Walker circulations) for completely different reasons. The link to tropical cyclones is tenuous at best. – gavin]
Re #295: Wayne, thanks so much for linking that. Speaking as someone who (when it comes to these sat photos) doesn’t know his ice from a hole in the clouds, I’d appreciate a little interpretation. Also, how do we know that the extent of leads and cloud cover is unusual for this time of year? Can that be documented somewhere?
So the next couple of seasons are shaping up to be very interesting eh!
• Arctic: With the old ice streaming out past Greenland over the winter, and the one-year ice full of leads in February the possibility of a prompt ice loss of all the one-year ice and further erosion of the older ice seems very real. We saw this northern-winter the impact of the sustained exposure of the Arctic ocean to sunlight for longer than usual. More will not be better!
• Extreme weather: The global higher energy climate has had its wicked way with a swathe north of the equator, with unprecedented snow, ice and rate of change. This has been accompanied by / caused by swings in the routes of high level jet streams which in turn appear to have been influenced by the unusual temperatures in the arctic. If these extremes are mirrored in the dry season we could be in for a boomer of a northern summer.
• Southern hemisphere: The thermal inertia of the southern oceans appears to be buffering us in the Antipodes from the extremes of change, however the stronger westerly circulation is impacting on more intense and out-of-season weather events. Some rains are providing a bit of relief in central Australia and in the dry areas of New Zealand. The impact on agriculture has been acute with some areas not previously known for dry being in dire straights. Some hope that this is a passing phase and normality will return. Others sensibly see this as a clear step on a progression to a climate regime that will not be sustainable for agriculture or in many cases habitation of the worst impacted areas.
Interesting times indeed!
Re: Gavins’s Response to #109
As I understand it, a diffusive model is about the best approximation one can get without resort to large scale digital modelling.
I should like to make some observations about diffusion of heat through ocean-like bodies of water.
With regard to surface fluxes and diffusion in general perhaps the most import consideration is that the diffusion equation relates time to distance squared.
With regard to penetration due to a linear surface Temperature/time increase; the depth increases with the square root of the time. Regarding surface flux it too increases with the square root of time since the onset of the linear increase.
From this one can calculate an “effective depth” of coupled ocean provided one knows when the trend began and the effective diffusivity of the ocean below the surface layer, i.e. the layer that is so stirred by the elements to be considered to act as a slab with a homogenous temperature relationship.
Now we have a steer from the oceanic temp/depth profile to likely values of the effective diffusivity and it is much (about 10^3) greater than the lab measurements due to local mixing.
Plug this in and one gets about 3600m^2/yr which results in an apparent effective layer that increases according to the relation 18m/sqrt(yr). There is a 4*pi factor that applies between the two relations.
This is considerable by most standards, after 36 years it would give a thickness of 108metres above and beyond any mixed surface layer. After 64 years 144metres.
Now it is easy to compute the thermal capacity of 108 or 144 metres of water and combine this with a likely value of the climatic sensitivity and get a time constant and this could be rather misleading.
The problem is that this “effective” depth may satisfy the flux equation for linear forcing but it does no imply that this layer obeys the basic Flux varies as dT/dt equation of a true capacitive body. As time goes by it more resembles the Flux varies as Temp-Temp(t=0) relation of a conductive body.
In the (dT/dt) case a period of constant temperature implies zero flux even if proceeded by increasing temperatures. In the diffusive case a similar period of constant temperature or even a significant negative downturn can imply a continued but decreasing flux.
This is handy as it means that a month, year or greater flat or negetive period does not necessarily imply that downward flux is not still positive.
Another important difference between the totally homogenous well mixed layer and a diffusive system is that, given a linear increase in surface temperature, in the first case the flux will be constant (dT/dt is constant by definition) in the second diffusive case the flux will increase year on year.
Now what might this mean? Well in a diffusive model one has to be very careful how one thinks about any time constants one might try to deduce from the behaviour of the model. One has to remember that it will react much more quickly to short term blips (volcanoes etc.) than a slab model but more slowly to multidecade events. Specifically the behaviour to a levelling off of a forcing (like CO2) would have a more sudden initial response than a slab model but followed by a very, very long tail.
Best Wishes
Alexander Harvey
#297, Steve, save the best pictures has they change every 40 minutes. Leads appear missing in the cold zone North of Ellesmere, they are there, perhaps not so numerous but it is so cold that the ice surface appears polished (its -45 to -50 C around there). West of Banks Island you can see a mix of new and old ice easily by geometry and shades of grey. You need to go back and study multiple years of previous ice pictures at the same resolution to appreciate the number of extra leads particularly amongst the new ice.
Nigel, there is more to temperature than can be found on the surface, despite what appears to be very cold ground temps, there is quite a warming just above:
http://www.weatheroffice.gc.ca/data/analysis/saa_100.gif
from -45 to -50 to just -10 C at 850 mb…. Also over NE Russia equally warm, that has been
in a nutshell what happened here this winter so far. February just ended data had Density Weighted Temperature similar to last year (almost identical) `but surface temps much colder, the heat didn’t vanish, in some parts it just rose.