lucia has asked me to blog on this season’s Arctic sea ice. There will be more later, but here’s the current JAXA version 2 seven day moving average plot for the 2009-2014 minimums. I’m hoping I can keep this graph updated more or less daily.
Edit: I’m adding a few more graphs.
Projected JAXA 2014 Minimum Ice Extent based on average loss to minimum from 2007-2013 (previous JAXA version numbers, don’t ask)
Arctic sea ice area anomaly (Cryosphere Today data) based on the average daily area from 2007-2012. You can call this cherry picking if you want, but I still think it’s interesting that the linear fit has a slightly positive slope for nearly 8 years.
PIOMAS average Arctic ice thickness.
PIOMAS Arctic Sea Ice Volume Anomaly.
Of course, things could still fall off a cliff in August. The AMO index jumped up in July after six months of near zero values.
I maintain a plot here of JAXA and NSIDC (NH and SH) data. It’s a polar plot, not smoothed. There is also tabular data (scroll up).
It seems JAXA has 2014 just now dropping below 2013 in ice extent for the day.
Nick Stokes
Thank you so much. Is this circular representation your doing? So interesting. And then the enlargement helps put things into perspective.
Ri,
Thanks. Yes, I did the polar plot – it seems the natural way to represent the periodicity. You can enlarge different sectors, mark year curves etc.
Nick,
Very illuminating. It puts the “death spiral” hype into stark perspective.
I’ve updated the post with a few more graphs.
De Witt
The Antarctic Southern Hemisphere Sea Ice Extent with Anomaly map at Wuwt still has small holes in multiple spots (small black spots). If these are being counted as water it would make the volume less than it really is.
On the Arctic Sea Ice Extent with Anomaly no such spots. The extent is quite down but the PIOMAS, is very high all the ice left must be very thick.
Some re freezing occurring east of Greenland, a large hole just infilled which makes it surprising that the extent is still falling unless there is a lag between the time of picture and the graphs (possible).
The AO index has just turned positive after nearly 2 months negative but the temp above 80 N is now under freezing and will stay that way hastening refreeze.
Re: angech,
Here’s yesterday’s data from the AMSR2 satellite. It does appear that there are spots of lower concentration scattered through the ice. It looks quite normal. Unless you can find data from last year at this time that doesn’t show those spots, I wouldn’t worry about it.
Thanks for confirming it. No, I have never seen it before in 4 years of looking at the charts. The small areas adjacent to the coast all over are quite odd though the spot on the coast at about 2.45 as on a clock seems to be present as a semi permanent feature. The others should not be there unless something weird is happening.
Angech
The area graphs count the dark spots concentration level, the extent plots count everything above 20% (or was it 15?) as a 100% filled pixel. They do it because often the dark spots aren’t known as accurately as we would like.
DeWitt, I like your very readable graphs. The contents have me thinking more about the analyses I have already done and what I could do in the future.
My current analyses were triggered by the Cowtan and Way (CWH) recent publications of their temperature data base that claims to get a better estimation of the Arctic temperature trends. I used their hybrid data (satellite and kriging) and found that the Arctic acceleration was greater than that of the other commonly used temperature data sets. I thought I might test their data against something temperature related like ice area or ice extent. I found an excellent correlation of annual average ice extent and the area weighted annual temperature anomalies for the zone 70N-90N with an R^2=0.86 for the period 1979-2012. For GISS I obtained R^2=0.76. The average annual ice area correlation with temperature was not nearly as good.
In order to minimize the existence of a spurious correlation I took the ice extent correlation a step further by correlating the residual ice extent (from the regression against time) against the temperature anomaly. Here the correlation yielded an R^2=0.46 There is no correlation of year over year changes for the product of monthly average open Arctic sea and monthly average solar radiation versus winter mean temperature anomalies. These are all based on the 1979-2012 time period. The indication here is that rising Arctic temperatures predictably cause more open sea but that feedback on temperature cannot be detected in this manner.
Your depiction of the sea ice thickness makes me wonder how well that might correlate with temperature anomalies. I also noted that your 7 day moving average shows little or no crossover for the various years and time period portrayed. I do not know whether that is a common feature of other years or what it means it terms of the physical variables involved in minimum ice extent.
I have done some research attempting to find a predominantly conjectured mechanism(s) for the Arctic acceleration in the literature without seeing an good agreement.
Re: Kenneth Fritsch,
Thanks, I tried. I take no credit or blame for the ice thickness plot, though. That’s linked directly to the PIOMAS page.
I should put up the graph of the ice anomaly vs the AMO index. I am still of the opinion that shifting ocean currents play a major role in polar sea ice dynamics. There was a significant decrease in sea ice and a significant increase in temperature around Svalbard in the early 20th century. Not coincidentally, IMO, that was when the AMO index went from declining to increasing. Assuming that whatever process drives the AMO index is, in fact, quasi-periodic, it’s due to start decreasing about now.
I can make no claims about the mechanism(s) for temperature change in the Arctic – as in amplification, but I did want to know whether ice extent was correlated with temperature anomalies and particularly year over year changes. Supposedly from what I have read if the change occurred primarily due to changes in atmospheric currents it should be detected in changes in the troposphere. I took a quick look at that record and did not find anything that conclusive.
Actually before Cowtan and Way only GISS made temperature extrapolations over the Arctic zone. Cowtan and Way make claims about their extrapolations being better than GISS – and satellite. I think the sparse temperature data for the Arctic zone has something to do with the lack of any clear cut explanations for the Arctic amplification. The models for the most part do not match the observed record and most show a significantly lesser amplification than the Cowtan and Way Hybrid (CWH) temperature data set. CWH shows an ever increasing amplification with latitudes north 60N with the greatest amplification in the winter months and the least in the summer.
What I found surprising with CWH, and to lesser extent the other temperature data sets, is for the period 1997-present, the large portion of the global trend that the small weighted Arctic area contributes. The globe has essentially paused during that time and particularly the area south of 60N while in CWH the warming above 60N continues at the same elevated pace. What is the source of the extra very large warming?
Re: Kenneth Fritsch,
There’s still a very large temperature gradient between latitudes greater than 60N and the rest of the NH. One could argue that the ‘missing’ heat isn’t going into the deep ocean, it’s being radiated to space at high northern latitudes. Given the lower temperature, at constant relative humidity it takes a lot less energy to warm the air above the surface at high latitude than it does in the Tropics. In the Tropics the enthalpy change from an increase in temperature is mostly latent heat from increased specific humidity, not the sensible heat from the heat capacity of the dry air.
I’m going to be away from my computer until Tuesday, so no more updates until then.
Arctic sea ice extent seems to be all the rage at other blogs, except Arctic Sea ice blog. Perhaps Neven should not have said it was boring. Comments there at an all time low due to the increase in Arctic Sea Ice or perhaps they have all gone to Bali.
De Witt some of the graphs show a very early, unprecedented upturn.
Is this due to the much thicker remaining ice?
Would it imply a possible three years of ice recovery if it keeps going.
Re: angech,
Cryosphere Today Arctic area is still declining and is slightly below 2013 for the same date, so I’m not sure what is the effect of the thicker ice at the end of July. I haven’t looked, but I’d be surprised if anyone is even attempting to navigate the Northwest Passage this year.
A few yachts are making the NWP transit this year. It just opened up a little.
http://northwestpassage2014.blogspot.ca/
Re: RobertInAz,
Considering how many got stranded last year, I would say ‘attempting’ rather than ‘making’ until someone actually completes the passage.
RobertinAZ,
That Trident yacht is amazing. And all for only $11,000,000! (plus operating costs, lol)
Re: hunter,
If you have to ask how much it costs….
If anyone made a mental bet on UAH for August, the actual value was 0.20.
DeWitt (Comment #131666)
Your points are well taken.
“One could argue that the ‘missing’ heat isn’t going into the deep ocean, it’s being radiated to space at high northern latitudes.”
That’s what I was thinking, but better you say it than I.
I am awaiting researchers to start using the Cowtan and Way temperature data set for the Arctic and the greater amplification that it implies. It does make the average CMIP5 climate model Arctic amplification further off the observed mark.
Steven Mosher | September 2, 2014 at 2:18 pm |
re C and W told me to rerad it
http://www-users.york.ac.uk/~kdc3/papers/coverage2013/update.140404.pdf
” No matter what data set we throw at the problem, the answer comes out the same.
Hadcrut and Giss get the arctic wrong.
For the above analysis, I passed on AIRS data to C&W.
For the longest time skeptics criticized the methods of hadcrut and GISS.
There is not one bit of data, not one shred of evidence, that Hadcrut and GISS are right. None. zero. nada”
But the article says
“The 3 problem stations account for nearly 40% of the difference between GISTEMP and CW14. Other unidentified differences in the station data at locations present in both datasets also contribute nearly 40%. The remaining difference arises from stations present in CRU but absent in GHCN.”
All of the difference between GISTEMP and CW14 in the Arctic can be accounted for by differences in the input station data.
So we got rid of the low outliers and hey presto the world is warmer in the Arctic at least.
“No matter what data set we throw at the problem, the answer comes out the same”
Obviously, you haven’t thrown data sets at the problem where the answer comes out different, then.
Andrew
RE: DeWitt
“There’s still a very large temperature gradient between latitudes greater than 60N and the rest of the NH. One could argue that the ‘missing’ heat isn’t going into the deep ocean, it’s being radiated to space at high northern latitudes. ”
——————————————————–
In general terms, I think this is how earth’s climate works. Excess heat enters the oceans mostly in the tropics under minimal clouded skies, is transported north by wind and ocean currents, and slowly exits in the arctic over many years while melting some ice in the process. Paleo ice core records show similar patterns during earlier warm periods but this seems to have been overlooked or under-appreciated in AR4.
Re: Andrew_KY (Sep 3 07:26),
And you know any such data set exists? You can do anything with imaginary data.
Re: ivp0 (Sep 3 09:19),
That’s obvious from the data for absorption of solar radiation and emission of LWIR from the atmosphere. There is excess absorption at latitudes less than ~40 and excess emission above 40.
graph
One can also argue that the closure of the Isthmus of Panama increased heat flow to high latitudes, which caused global cooling and the current series of glacial/interglacial cycles. The timing is about right.
“And you know any such data set exists?”
No. But That doesn’t mean nobody can compile one. That’s my point. I’m a little suspicious of a series of data sets that always give the answer you are looking for.
Andrew
Dewitt, it seem counterintuitive that the creation of the Gulf stream by the closure of the Isthmus of Panama caused global cooling of 10-15 degrees in the Northern hemispheres necessary for the glaciation advance. Certainly, more precipitation necessary for glacier formation, but the northern oceans are warmer.
Re: Phil B,
It does seem counterintuitive. However, the paleo evidence is fairly strong. Extended hothouse conditions have been associated with a free,near equatorial ocean circulation path. See most recently, for example, the Cretaceous Period with the Tethys Ocean separating the two supercontinents Laurasia and Gondwana just north of the Equator.
See also here:
And also see here: How the Isthmus of Panama Put Ice in the Arctic
As recently as 7-4.5 million years BCE, the climate of northeastern Tennessee was sub-tropical as evidenced by fossils recovered at a site near Gray, TN.
PIOMAS has updated. It looks like the minimum volume will be higher than 2013 and more than twice as high as 2012.
Re: Andrew_KY,
And if pigs had wings….
“And if pigs had wings….”
I bet you could do it. 😉
Andrew
Dewitt, thanks for the links, but the arguments in “How the Isthmus of Panama put ice in the Artic” weren’t very convincing. The argument is that when the isthmus was formed, it revved up the gulf current and created more precipitation in northern Europe and western Siberia and the fresh water from Siberian rivers that flow into the Arctic ocean and then freeze and that ice causes cooling of the Arctic and slowing of the Gulf current. They seem to argue that the revving up of the Gulf current creates a massive negative overshoot to the climate. I don’t buy the argument. They also stated that the gulf current made it way to the Pacific around Africa and the Indian ocean and then ultimately return to the Atlantic which contradicts some of the graphs I have seen.
I have not seen any graphs on North America’s location 7 million years ago but tectonic plate movement could account for subtropical fossils in Tennessee
Re: Phil B,
See here.
The movement of North America has been mainly longitudinal, away from Europe, in the last few million years, not latitudinal. And it was the global climate that was warmer in the late Miocene, not just the local climate in TN.
Greenland, however, has been moving northwest for the past 55 million years, and at 18 mms/year northward, it has moved 990 kilometres towards the north pole in that time period.
http://sideshow.jpl.nasa.gov/post/series.html
It slowly became more and more susceptible to the downturns of the Milankovitch Cycles and the snow did not melt completely in the summer, starting first in the northern portion about 5 million years ago. Then glaciers started accumulating in the the central and southern regions at 2.7 million years ago. Earth’s Albedo goes up, ice ages begin.
Re: Bill Illis,
Greenland is only 0.4% of the area of the planet. It isn’t large enough. Besides, it’s the other way around. Ice ages begin and are reinforced by the increase in albedo.
Milankovitch Cycles alone do not explain ice ages or even glacial/interglacial transitions within ice ages. See the Ghosts of Climates Past series (part I here) at Science of Doom. I think you might be surprised at how little we actually know about the dynamics of ice ages.
Greenland is only 0.4% of the area of the planet. It isn’t large enough.
———————-
How would you know that.
I built an Albedo calculation model and it (along with Ellesmere Island) are just big enough and far enough south to kick off an ice age when they are in the deepest downturn of the Milankovitch Cycles so that the snow does not melt in the summer.
After that, the glaciers slowly build southward (causing a larger and larger impact on Albedo) until there is a large enough increase in northern high latitude solar insolation over a long enough time to melt back the ice volume that builds up (starting from the southern limits).
Re: Bill Illis,
And models work so well. /sarc
I’m reminded of WHT and his wiggle matching.
That all sounds good, but if you look closely at the timing of the transitions from glacial to interglacial and back again, they don’t match the Milankovitch Cycles very well at all. The second problem is that the Milankovitch Cycles are used in the determination of the time scale, so there’s a certain amount of circular logic there.
Before humans invented agriculture, no trigger was needed for the transition from interglacial back to glacial. Interglacial climate wasn’t stable. The much more interesting problem is how do glacial periods end. Hint, it almost certainly isn’t Milankovitch Cycles. In fact, it’s not at all clear what it is. The latest proposal is that it has to do with the dynamics of the ice sheet itself.
DeWitt,
I think the isostatic rebound delay (slowly increasing elevation where ice sheets melted) is the best rational I have heard for what triggers the process of glaciation. After all, a slow elevation change of nearly 1 KM will cause a very big change in surface temperatures. it sure as heck isn’t falling CO2, since ice cores show the last glaciation started with CO2 near 280 PPM, and it took many thousands of years for the CO2 to fall much. There has to be some CO2 feedback (of course) but it looks like a tiny factor compared to increases in albedo from snow and ice cover.
.
With current GHG forcing (and measured increases in high northern latitude temps), the onset of ice sheet formation seems unlikely for a very long time.
I read Comment #131686 above and intuitively (and ignoring issues such as clouds) it seems evident that transferring more energy from the equatorial to the polar regions would lead to more energy escaping even if there´s increasing green house gas concentrations, in part because the colder air in the higher latitudes is so much drier (this means the outgoing shortwave has a much easier ride on the way out?).
The first time I traveled up there I was shocked when I had to breathe really dry air, it´s so dry it burns the lungs.
Anyhow, so I was wondering if somebody may have prepared a simple model correlating the outgoing energy to LATITUDE, TEMPERATURE, and air HUMIDITY? Or do the clouds tend to make it yield goofy results?
Or do you just look up the measured temperature at the top of the atmosphere?
So, less H2O ( vapor ) does increase the ability of low level emissions to escape to space.
But that leads to cooling which reduces the amount of energy emitted.
Of course, when one moves the air from the equator to the pole, it is more able to emit to space.
Re: Fernando Leanme,
I believe the outgoing LWIR in the graph I linked above is measured by satellite rather than calculated.
That’s my problem, I’m always reinventing the wheel.
I guess when one starts out with a simple model and complicates it then it takes a supercomputer to run it, and it’s so complex nobody really understands what it does anymore.
Which makes me wonder, are the satellites going to improve to measure the full outgoing spectrum with 0.1 watts per m2 accuracy? Why not launch 200 satellites? If the USA has money to blow in Iraq and pick wars with Russia it ought to have money to launch the uss Enterprise with Captain Kirk aboard in 5 years.
I don’t think isostatic rebound is significant. It’s the orbital forcing getting muddied by the continent land mass being distributed unevenly and the ocean currents taking their time to react to the transient effects (I practically fell off my chair when they told me how long it took for water to reach the bottom of the North Pacific when I studied physical oceanography).
Which reminds me, is anybody working on accounting for geothermal flux in the ocean energy analysis?
fernando,
Rebound can raise land by up to 1 kilometer after ice sheets melt. That is about 6C colder on average just due to altitude. There are several published papers which address this issue.
Fernando,
“Which reminds me, is anybody working on accounting for geothermal flux in the ocean energy analysis?”
If you mean what I think you mean, that interests me too.
I am not talking volcanoes but a more general flux from the core.
Given the temperature down there I have long thought that there must be some heat from the core which must be heating the lower ocean to an extent.
I would also expect “hot spots” due to variation in the thickness of the crust and I would like to see a map.
Steve F (Comment #131716)
Rebound can raise land by up to 1 kilometer after ice sheets melt. That is about 6C colder on average just due to altitude.
Is trhere some sort of relativity problem here? In isolation a 1 km rise would give a big temperature drop but what goes “up” in 1 area must be down in another area??
The atmosphere is relative to the land/sea it is on of the whole earth and if something goes “up” somewhere then there must be other areas which are now lower to the ground??
The earth does not suddenly expand all over [well it might ] but the water keeping it down has now gone into the sea pressing other areas down.
The rebound question is very interesting. I have heard of it since I was a kid reading on geology. I had not followed it closely as a possible climate causative factor, but it sounds intriguing. Fortunately geologists have looked into this quite a bit. Here is an interesting brief summary of rebound studies.
These excerpts are particularly notable:
“We know that the weight of the glacier ice was so great that it depressed the crust of the earth. The earth’s crust behaves as an elastic structure and glaciologists know that, once the ice reaches a certain thickness, it depresses the crust about a foot for every three feet of ice (ice is roughly one third as dense as crustal rock). Normally, this deformation takes the form of gentle flexing and unflexing of the earth’s crust, although it can be accompanied by faulting and reactivation of large regional structures. Thus, when the glacier melts, the crust returns (rebounds) to the position it had been before the ice advanced over it. It may do this smoothly and gradually, or the rebound may happen in quick jumps, resulting in earthquakes as faults form. I’ve seen quite fresh appearing 20-meter-high fault scarps in Lapland, where deglaciation occurred relatively recently and rapid rebound is currently taking place, spasmodically, as earthquakes.
https://www.dmr.nd.gov/ndgs/ndnotes/Rebound/Glacial%20Rebound.htm
The greatest measured rates of isostatic or postglacial rebound in North America occur in the Richmond Gulf area of southeastern Hudson Bay (presumably where the ice was thickest). There, a kind of “staircase” of 185 Holocene (postglacial) strandlines (former shorelines) provide a continuous record of emergence from about 8,000 years ago until the present. At least 935 feet of recovery (isostatic rebound) has been recorded by these strandlines. By determining the age of these strand lines, and by subtracting the apparent component of uplift due to relative sea level fluctuations, geologists have been able to measure rates of isostatic rebound. The rates of uplift have declined from a maximum of 33 to 39 feet per 100 years immediately following deglaciation (8,000 years ago at Hudson Bay – in North Dakota deglaciation occurred about 5,000 years earlier) to a current rate of about 4.3 feet/100 years. In other words, the shoreline at Churchill, Manitoba on the shore of Hudson Bay is currently rising about 4.3 feet per century.”
I have not been able to find examples of one kilometer rebounds in my brief survey. But >900 feet is really impressive.
angech,
No problem at all. The reasoning goes as follows: The relatively more localized rise is large compared to the more diffuse fall, so the cooling is more concentrated in the region of rebound than the very small warming elsewhere from falling elevation. (The current sea level increase is about 0.3 mm per year less than it would have been in the absence of rebound, while local elevation around Hudson Bay is still increasing by cms per year.) Once the local temperature drops enough to maintain snow cover over the summer, there is a net negative global feedback from increase in albedo. The accumulating ice sheet very gradually depresses the crust, but continues to grow in net height for a long time, ‘locking in’ the ice age. At some point, summer insolation increases due to orbital changes, while the crustal depression has already lowered and warmed the ice sheet front; this starts a ‘runaway melt’, which builds on itself due to falling albedo as the ice melts.
Hunter,
The equilibrium depression can be calculated from the thickness of the ice, the density of ice and the density of mantle. I haven’t recently done the calculation, but if memory serves, the depression is about 30% of the ice thickness. The recorded shore lines around Hudson Bay can only show what happened since near the end of the deglaciation process; before that Hudson Bay was a huge ice shelf with no shorelines at all. The fastest pace of rebound is probably missed by the shoreline record.
Hudson Bay did not exist until the ice ages began; it was above sea level. It has been a relatively low elevation area for 100 million years since the Canadian Shield mountains were eroded away long ago and the area was partially flooded during the high sea level stand of the Cretaceous but it went above sea level not long after.
Its difficult to know how long an interglacial would have to be before Hudson Bay completely drained but its average depth now is only 330 feet. If the average amount of uplift has been 990 feet since the end of the last ice age and it is still rising at 4 feet per century, one can do the math.
There are many other areas in the northern hemisphere such as the northern coast of Siberia, the North Sea/Baltic, the Barents/Kara Sea which were likely above sea level before the ice ages started. They have been depressed below sea level by glaciers at some point in the last 28 ice ages which have occurred in the last 2.7 million years.
Now take all those areas and put glaciers on them at some point in the last 2.7 million years and what happens to the variability of Earth’s Albedo.
Re: Fernando Leanme (Sep 6 16:27),
The short answer is that no one with the power to spend that much money thinks it would be worth it. Even if there were the will to spend, you can’t build something that you don’t know how to build, like a starship, for example. Current ground based instruments aren’t even close to being able to make that measurement and I don’t see anything on the horizon that will change that.
Pick wars with Russia???? Let’s not go there. As author, I do have the power to moderate comments on this thread.
Probably more uncertainty in the shortwave anyway.
IR emission is roughly isotropic – the same in all directions.
Shortwave reflections take place in varying proportions to varying solar directions ( some reflected directly back, some scattered forward, some in all other directions in between ).
That means for shortwave, you need infinite sensors covering all directions, while for IR, a single sensor on a single satellite does reasonably well.
SteveF,
“I think the isostatic rebound delay (slowly increasing elevation where ice sheets melted) is the best rational I have heard for what triggers the process of glaciation. After all, a slow elevation change of nearly 1 KM will cause a very big change in surface temperatures.”
a yes, but comment [sorry] there would have been 3 kilometers of ice on these areas so the areas of ice would have been relatively 2 kilometers high which is another 6 degrees colder at the top.
conditions would have been even better for glaciation when it had occurred?
Not necessarily. Ice sheet formation can be precipitation limited, not just temperature. If for example, the Arctic Ocean was permanently frozen and assuming prevailing westerly winds, its a long way for moisture to travel from the Pacific to Hudson Bay.
I occasionally fly between Japan and the UK. The route takes a great circle, crossing eastern Siberia, flying parallel with the northern Siberian coast before turning SW over Finland. I have been struck by the absence of obvious glacial landforms (from 35,000 feet). The only exception to this are some clearly glacially scoured valleys in the Stanovoy range. Arguably, much of northern Siberia was free from significant ice sheets at the LGM. (I may be out of date here).
Re: Hector Pascal (Sep 8 03:45),
Ice sheet formation goes much further south in North America than Asia. One theory is that the geography of Arctic North America with lots of water separated land mass gets colder and stays colder than a contiguous land mass like Asia that would have warmer summer temperatures. Also, ocean currents may keep Baffin Bay, I think, open longer to provide moisture for local precipitation. That’s another possible Gulf Stream effect. I might be able to find those references again if I get around to it.
Thanks DeWitt. I’ll buy Baffin Bay/Atlantic as an alternative source for moisture for eastern North America. It has to be coming from somewhere.
Off topic if you’ll permit, flying west over Siberia in spring (April) is an amazing sight. Leaving Narita in late-morning, arriving Heathrow mid-afternoon after a 10 hour flight in constant daylight. Siberia is huge. Arctic Ocean solid with ice from the rh window. Siberian plain with sparse larch(?) from the lh window. Almost no signs of human activity apart from the odd seismic line. Lots of meandering rivers. Everything frozen, but very little snow. Rocks and geological structures very clearly visible. I’ve flown enough to be not easily impressed, but this is something.
When it was covered with the 3 Km ice sheets would the change in mass and shape have made the earth wobble ? TM angech
Re: angech (Sep 8 07:01),
It would be mass distribution, not total mass, but it would have a small effect. That’s the sort of thing the GRACE experiment measures, although current changes are much smaller.
By the way, the linked article on ground water depletion in the Colorado River Basin should curl your hair if you live in the US. As I remember, the last 100 years have been much wetter than the long term average from paleo records. This is indeed climate change, at least locally, and is something that changes in ghg’s in the atmosphere may not have caused and isn’t going to be fixed by small, or probably even large, reductions in carbon emission. It’s something we’ll have to learn to live with.
By the way, the reference to climate model predictions in the National Geographic article linked is irrelevant. Climate models have no skill at all for regional climate. Sub-grid modeling has not been shown to be any better than the climate models themselves that determine the boundary conditions for the sub-grid models.
DeWitt,
It is an interesting article. The message I hear is pretty clear: 80% of water usage is by farms, so any significant reduction in ground water use will have to take place mainly via farming practices. The disconnect between water use and water cost is ultimately the problem. Seems to me that only clear price signals will reduce water use on farms, but history shows farmers are likely going to have enough influence on politicians to block any meaningful increase in cost for irrigation using ground water. The most likely outcome will be greatly increased water cost for domestic and industrial consumption, but with only a tiny resulting drop in the rate of ground water depletion. Another case of “most expensive” combined with “least effective”; sort of like using solar cells to generate power in Germany.
Re: SteveF (Sep 8 13:40),
The surface water allocation system in California appears to be a total mess: http://iopscience.iop.org/1748-9326/9/8/084012/article I guess that shouldn’t be surprising when over 80% of surface water rights by volume are controlled by public entities.
Steve F, I questioned the isostatic rebound you quote because I have read unpublished data we use in the oil business. The loading history is important for rock sections which hold heavy oil (a rock layer which has experienced low vertical stress tends to have much higher porosity and compressibility. The classical examples of low stress histories are Long Beach and Lagunillas Fields.
As we study rocks sections we can easily see the porosity and rock compressibility are altered by loading histories. And based on what I have seen it seems to me what the glaciologists “know” needs a bit of double checking using geology. Ice is about 40 % the density of a “normal” clastic sequence . And I have never seen anything like the rebounds you quote from erosion of an equivalent section. This is more so if we consider the rocks are under cyclic loading. If this is going on where the hell are the faults?
I confess I could be absolutely wrong, what you describe could alter some of the way we model things when we do reservoir descriptions. So if you guys could give me a hint of where to look I would appreciate it.
Fernando,
Let’s make sure we are talking about the same things. The rebound I am talking about is due mainly to visco-elastic flow of the (very hot) mantel, not mainly deformation/compression of the crustal rock.
With regard to faulting/fracturing during rebound, I have no way to comment on how much of this there should be, though clearly there is some (see one of the earlier comments in this thread which describes rebound related faulting). I think the New Madrid earthquake is theorized to have been due to isostatic adjustment.
Re: Fernando Leanme (Sep 8 15:12),
During glaciation, the continental plate tilts and sinks while the sea floor rises because the mantle flows and the continents effectively float on it. Mass is removed from the ocean, lowering the static pressure on the sea floor and added to the continental plate, raising the static pressure. The reverse happens during deglaciation. Compression of the crustal rock is not significant compared to this movement. The resulting effect on measured sea level is referred to as the Global Isostatic Adjustment.
http://sealevel.colorado.edu/content/what-glacial-isostatic-adjustment-gia-and-why-do-you-correct-it
SteveF:
More recently (more or less synchronous with improved observational ability), I think it is just considered to be associated with a more active geological region than was previously thought.
Steve F, I realized you were discussing post glacial isostatic rebound. However, we use both terms: 1. the ice loads and rebounds and 2. the vertical stress, the changes in rock volumes, and the subsequent reduction in stress as rocks are either eroded or the rocks are brought closer to the surface by tectonic forces.
I´m not a geomechanics specialist, but I worked with them and had to make sure they used the appropriate data. We use analogues, which require we understand as closely as possible the loading histories.
However, I think you can relax. As you can imagine my intuition is based on what i had absorbed from studies in hydrocarbon bearing areas and nearby cratonic sources. When I dropped the subject last night I started to slap myself because I had made a mistake. I always emphasize NEVER to extend one´s intuition or knowledge to areas one hasn´t studied. And that´s what I did last night.
So this morning I went ahead and calculated the maximum rebound in that spot near Hudson Bay and arrived at a MAXIMUM of around 700 meters.
If you want to read more I left a trail here
http://21stcenturysocialcritic.blogspot.com.es/p/labrador-and-hudson-topography.html
By the way I realize I got on my soap box about politics, but it does seem to me it´s truly shameful to see how scientists have to scrounge for data. I have an an oil company background, when it comes to needing information to make informed decisions top notch oil companies really muscle up, but it seems governments are kinda weak.
De Witt, within this context you are right regarding the relative importance of vertical stress loads and the rock section shrinking near the surface.
However, use your calculator and imagine what happens if 1 km of 2.5 gm/cc rock is removed by erosion. That´s equivalent to removing about 2.5 km of ice, isn´t it?
I was also thinking the mantle viscosities would not allow the rocks to bob up and down fast enough to have a cumulative 1 km bounce. My reasoning was that because the rebound rate decays the next ice age starts before it has reached “stability”. So what must be happening is a series of gradual push downs, with a sudden load release, and an initially fast rebound which decays at an exponential rate.
So it sort of bobs up and down. This bobbing motion upwards may indeed be a positive feedback for the next glacial stage. And that was the point, right?
Fernando,
Your oil industry insights are really interesting. The rocks tell the truth and the oil industry has billions in the game of making accurate decisions based on the rocks.
The summary of altitude changes due to rebound I linked to suggests that at most there is about 1,000 feet of rebound in the most extreme cases. I doubt if a global ice age is going to precipitate from that much uplift. Whatever it is that causes continental glaciation is not likely to be centered on that, it would seem
Hunter, that’s more in line with what I was told. I used an old technique to estimate that 700 meters upper bound. However I’m also good at cutting corners. Any time you want to ask anything about oil or in general what we do just feel free to ask. A lot of what the media publishes is garbled.
Ref Hector Pascal’s comment: flying over Siberia is indeed an amazing trip. I never understood Russian culture and the way they think properly. But I assure you the land does make them different. The Russians also have gone deeper in areas we never thought about. They sure love their math. And they have a lot of data we found was plotted with the wrong geographic coordinates on purpose. It was an old fear the German invasion issue.
Fernando,
Thanks. Geology and meteorology have been life long interests of mine Growing up in and living in Houston has allowed me to know a fair number of geologists as neighbors, friends, clients. The discipline that comes from actually having to do something right would be very beneficial to the climatocracy. Richard Betts now openly states that the models are no good for policy making but that the climatocracy’s policy demands must be implemented anyway. I think that in the oil patch if a company was run like the climate clowns behave the company would soon be merged off and the employees laid off asap. The Russian insight is quite interesting. I am working with a Ukranian/Russian couple right now and the emotional tension is quite moving.
angech,
Antarctic sea ice area is currently on a run and is within 0.04 Mm² of the all time record. That record was set on September 20.
Dewitt (#131828) –
According to this, the latest (Sept. 13) value of Antarctic sea ice area, at 15.873 million km^2, *is* the highest. You must have a different source.
P.S. (pedantic question) Is the proper SI term for 1 million km^2, 1 Tm^2? I’ve never seen any such use. It’s always presented in millions of km^2.
Re: HaroldW (Sep 15 09:46),
Different source. I was using Cryosphere Today, which doesn’t have a nice table like that. CT’s numbers are higher. The highest ever for CT is still September 20, 2007 at 16.2323818 Mm², which, btw, is the correct SI suffix for 1E12 m². 1,000 km is 1 Mm. Square that and you get 1,000,000 km² or 1Mm². The CT value of 16.2028 Mm² is also for September 12, so your source is a day ahead. It’s likely that the CT value for 9/13 will be a new absolute high record.
1 Tm² would be 1E18m².
Dewitt –
Thanks, I’ve seen CT’s graph, but hadn’t seen the table of values, and the other one came up on Google with a nice table.
Also, thanks on the SI question. It makes sense, as we write km^2 for a square kilometer = (km)^2, rather than meaning 1000 (kilo-) square meters. So by that logic, Mm^2 = (Mm)^2 = 10^6 km^2.
Re: HaroldW (Sep 15 12:06),
In fact, that’s precisely the logic that SI uses. I went through this with Nick Stokes a while back and actually looked it up.
De Witt
“Cryosphere Today, The highest ever for CT is still September 20, 2007 at 16.2323818 Mm²”
15/9/2013 is 16.203 and looks like going higher
Fingers crossed.
The anomaly is 1.133 greater than normal but earlier this year was 2.0 million more than normal
Imagine if that had happened at this time of year It could have reached 17.00 million!!
looks like these temporary winds circling Antarctica are taking up permanent abode.
Cryosphere Today Antarctic sea ice area set a new absolute high of 16.3944Mm². Given the rate of increase over the last few days, tomorrow could be higher.
Antarctic ice area inched up a bit more to 16.48 Mm². The pattern in the baseline is that area dithers aimlessly for another week or so before heading down.
Cryosphere Today Arctic sea ice area may have hit bottom a few days ago. The minimum, if it was the minimum, was almost identical to 2013, 3.5557Mm² compared to 3.5544Mm².
That was weird. Somehow FireFox stuck a plus sign between my first and last name. Saved a lot of time being able to moderate myself.
The JAXA seven-day moving average of Arctic sea ice extent is of paramount interest, because quatloos depend on it. I see that the latest average is 4.929 Mm², so my wager of 4.949 is already a loser.
It’s running a shade higher than 2013, but below 2009.
Re: HaroldW,
Good point. I’ve altered the graph to label the value of the last point. When the average starts increasing, I’ll keep the label on the minimum.
I’ve expanded the scale on the projected minimum chart. The values are the previous JAXA version calculated by a linear transform of version 2. As you can see, we’re really close to the minimum unless something unusual happens like in 2010.
Right now it looks like a tie between BobD and DavidJay who both picked 4.9. Ray’s original estimate is right on today’s value, but he changed it and is way out of the money.
Would someone care to updateus on what William Connolley will be spending his sea ice projection betwinnings on in 2016
..he is on track to win isn’t he ? ha ha
http://rankexploits.com/musings/2011/connelly-dekker-bet-actually-robs-got-a-very-good-chance-of-not-losing/
note how the media predictions were all wrong about the Scottish Referendum ..and the bookmakers were all right. So has any alarmist won any money from the bookie s?
To recap the bet between Rob Dekker (RD) and William Connolley (WMC), from the above link:
After 2012, with JAXA mean Sept. sea ice extent at 3.4 million km^2, it looked favorable for RD. However, 2013 came in at 5.0, as will 2014, so at the moment WMC would seem to have by far the better chances. However, there are still two years to go, and it wouldn’t be surprising if the 2016 figure lies within the “push” zone of 3.1 to 4.8.
.
NSIDC figures for Sept. 2012 & 2013 resp. are 3.63 and 5.35, well above JAXA’s. That means it’s even less likely that RD would win (than looking solely at JAXA).
.
The answer, of course, is blowing in the wind.
HaroldW,
Off hand, odds seem to favor WMC or the gap zone where no money changes hands. I guess I’ll have to have a look at the end of September.
If it’s really close, I suspect there will be finagling about JAXA version 1 and 2. Version 2 has lower minimums than version 1, which was in place when the bet was made. However, if the AMO has indeed turned the corner and started down, it’s looking bad for Dekker. For a preview, watch the PIOMAS volume data.
And in other news, the Cryosphere Today Antarctic sea ice area continues to set new records. Perhaps 17 Mm² isn’t out of the question. The global sea ice area is back in positive territory and the rank for the value posted today is 7th highest anomaly for the day of the 36 years of data.
NOAA near real time Arctic extent also looks like it’s bottomed. The average for the month so far is 5.16Mm² and if the minimum has been reached, that could increase. The monthly data are also usually higher than the near-real-time average.
“the Cryosphere Today Antarctic sea ice area continues to set new records. Perhaps 17 Mm² isn’t out of the question”
They will have to change the graphs, the top level only goes up to 17 million.
What I do not understand is how quickly, in a matter of weeks, total sea ice can go up or down by over 800,000 sq K. With changes like this who could say if the Arctic became ice free for a year or so, or if the Antarctic froze up to 18 million that this was not simply natural variation?
JAXA daily Arctic sea ice extent has increased for the third consecutive day, and the 7-day average has turned upward. So I think the minimum has been reached, and the lowest 7-day average will stay at 4.899 million km^2.
HaroldW,
WE’ve either hit it… or… soon. Usually you can’t be sure. But it is late September, so I think we’ve probably hit it.
Whatever the lowest 7-day average turns out to be for 2014, it is now clear I will not be winning this year’s contest.
This is most depressing. Maybe spending some time reading today’s edition of Mark Steyn Online will cheer me up.
Re: angech,
Remember that it’s not ice and no ice. The actual satellite output is ice concentration per pixel from zero to 100%. Pixels with concentrations below a certain level, like 15%, are ignored for calculating area and extent. So it’s possible for large changes in the totals when the real amount of ice doesn’t change very much.
I would say that we’ve likely seen the peak of Antarctic area at 16.8Mm², because it’s stopped increasing rapidly and was less than the day before for the latest posting.
Also, every Arctic index I monitor look like it’s reached a minimum and started back up. I would still wait a few days, though, before calling it official.
The preliminary read is 5.02 million square miles (from NSIDC).
Re: RickA,
Preliminary read of what? 5.02 million square miles is 13.0 million square kilometers. NOAA near-real-time extent minimum so far is 4.98339 Mm² (= million square kilometers, see above) on 9/16.
Sorry DeWitt – your right.
It is 5.02 million square kilometers (from NSIDC).
Here is the link:
http://nsidc.org/arcticseaicenews/2014/09/arctic-minimum-reached/
De Witt,
I would say that we’ve likely seen the peak of Antarctic area at 16.8Mm², because it’s stopped increasing rapidly and was less than the day before for the latest posting.
Also, every Arctic index I monitor look like it’s reached a minimum and started back up. I would still wait a few days, though, before calling it official.”
There seems to be a disconnect between the end of freezing and the end of melting, ie they do not seem to occur at exactly the same time for the 2 hemispheres at this time of year. Why?
It does not happen at the other crossover in March.
We are at that stage where total sea ice increases rapidly for the second time in the cycle.
angech,
Very different heat capacities in the two hemispheres lead to different rates of warming and cooling. The lower heat capacity in the north (more land, less ocean) means the north should warm and cool faster than the south. Another big influence is the thermal isolation of Antarctica; warm air from lower (warmer) latitudes can’t easily get past the cold Southern Ocean to accelerate summer melt.
Re: angech,
Orbital mechanics probably has something to do with it. Eccentricity is currently putting perihelion in early January, after the SH summer solstice. Also, the albedo in the high latitudes of the Southern Hemisphere is a lot higher than it is in the NH. The Antarctic ice cap alone is almost as large as NH sea ice gets, and that’s there year round.
The latest fallback positions of the cliamte consensus regarding sea ice is that it was much thicker X years ago. My question is how is it that Arctic sea ice thickness was well known before the satellite age?
thanks.
I wish I had stuck with my original bet of 4.913!
Hunter, the most reliable method was to take an ice breaker through it, drop two college students on the ice and force them to make a line of holes. I think we also did fly overs to count ridges, cored the ridges and the multiyear ice. But we were in a transition period when we did get some military satellite data. I also knew a guy who told me we had indirectly obtained USA submarine data taken from underneath, and used it in ice charts we had to estimate the vessel navigation time statistics we input in our models. I felt it wasn’t that reliable, but that’s all we had. However in some areas it’s easy to tell by checking whether a vessel can get through at all. If it can’t it means the ice is very thick.