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Al Rodger
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Hi Kevin, Yes. He has put his latest Global figure up here. But the page you link to with all the sea/land figures for different latitudes (ie the Arctic) is still only showing to February. It usually is updated quite promptly. Nomad3 is updated for March with SST showing record warmth above 65deg & 80 deg. But it seems to me that ice is more affected by TLT figures.
Toggle Commented Apr 9, 2014 on PIOMAS April 2014 at Arctic Sea Ice
The link that hopefully now works.
Toggle Commented Apr 8, 2014 on PIOMAS April 2014 at Arctic Sea Ice
The data from Rutgers Uni shows NH snow cover now tracking 2012, the record year for early snow melt. It's early days mind. (The graph here (usually 2 clicks to "download your attachment) shows the 2014 anomaly against previous decadal & the 2010-3 averages). UAH should update for March soon so we'll know whether the Arctic's Lower Troposphere record temperatures remain or have dropped down a little.
Toggle Commented Apr 8, 2014 on PIOMAS April 2014 at Arctic Sea Ice
Chris Reynolds, I think the discrepancy between our two figures is you have managed to use 1 hour days. 67 ZJ x 24 = 1608 ZJ ≈ 1,600 ZJ (Note a comma is used not a decimal point. Sorry for the confusion caused.) Perhaps to add reason for why I see a 3m 2100 SLR is "exceedingly pessimistic", it is worth pointing to Vallis & Farneti (2009) who show a figure for the meridional heat transfer into the two polar regions of 2 x 1.5 PW or ~100 ZJ pa. This represents about 3% of the planet's 3,850 ZJ solar heating being sucked towards the poles because they are comparatively so cold. My exceedingly pessimistic" SLR would require 20% of the additional warming to be sucked towards the far smaller Greenland & Antarctic ice sheets due to a far smaller temperature differential.
Toggle Commented Mar 22, 2014 on PIOMAS March 2014 at Arctic Sea Ice
I think a few numbers may benefit the discussion. To give 1m SLR from melting ice, you will require 125 ZJ for the melt plus probably 10% coz the ice is actually well below freezing = 140 ZJ. Solar insolation is mainly used to keep the planet at 288ºK. Start pinching it to melt ice & the global temperature plummets. What is relevant is the TOA energy imbalance. If this is 1 Wm^-2, the extra energy sloshing round the climate after a century will be 1,600 ZJ. But if the ice remains awaiting melting at the poles, most of that 1,600 ZJ will end up heating the tropics, and then keeping it warm. And if the poles also heat up, there will be more energy needed to maintain that polar temperature increase. So let's say a very very generous 20% is the maximum that will be available to melt ice. Using 20% of the 1Wm^-2 imbalance for melting, that gives 2.3 m SLR in a century/Wm^-2 imbalance. Say the imbalance is a third the forcing & forcing rises from 2Wm^-2 today to 6Wm^-2 in 2100. The average over the century would thus be 4Wm^-2 forcing = 1.3Wm^-2 imbalance = 3m SLR. And that's from both poles. These numbers are in my view exceedingly pessimistic. But that is what is required to get multi-metre SLR by 2100 without the ice leaving the poles in search of the heat.
Toggle Commented Mar 21, 2014 on PIOMAS March 2014 at Arctic Sea Ice
folke_kelm, The famous paper on the internal temperatures of the Greenland ice sheet is Dahl-Jensen et al (1998), memorable because it presents a temperature record preserved within the temperature gradients.
Toggle Commented Mar 20, 2014 on PIOMAS March 2014 at Arctic Sea Ice
Martin Gisser, I would agree that there is not enough data to foretell the future rates. Who knows? This coming melt season could show serious increases in melt-rates. The one problem ahead is that GRACE is getting old and there is no replacement so we'll soon be back to divining ice loss with the tea-leaves. I'm not clear as to why nonlinear ice loss would make an exponential model the natural choice. And a constant acceleration is also nonlinear. (That 30Gt/y was derived from a regression on this data a few years back now - I'm as surprised as anybody that the melt rate has stuck to that line.) As for 1m, 1.2m by 2100, there were a lot of papers pointing to such a rise. Has this now changed? Is Gavin now signed up to multi-metre 2100 SLR?
Toggle Commented Mar 19, 2014 on PIOMAS March 2014 at Arctic Sea Ice
idunno, You can indeed say that over the last 8½ years the 12-month rolling average has increased from 150Gt/y to 400 Gt/y. That would be equivalent to 3.2x in a decade. And if you add on the last years data its down to 440Gt/y. But here is a problem. That annual increase follows the 30Gt/y/y line to get there. There is no increase in acceleration. (I shall upload the updated graph to show the latest data.)
Toggle Commented Mar 19, 2014 on PIOMAS March 2014 at Arctic Sea Ice
One point I disagree with Jim Hansen is his 5 metre SLR by 2100. I would argue that the only way such a rise is possible is from ice caps shedding icebergs. There is simply not going to be enough energy available at the ice caps themselves to melt enough ice. Thus I would argue that anybody presenting such an argument needs to point to that source of icebergs. I also do not see any sign of the "doubling" which would be required for a 5 metre rise by 2100. The Greenland ice loss is perhaps less ambiguous than the Antarctic loss. The Greenland loss is accelerating (usually 2 clicks to 'download your attachment') but I don't see in this data any sign of an increase in this acceleration. Thus I see no "doubling".
Toggle Commented Mar 19, 2014 on PIOMAS March 2014 at Arctic Sea Ice
A 'heads-up' for out host. The JAXA links on the ASI Graphs page have passed their sell-by date. The JAXA Extent data is now at http://www.ijis.iarc.uaf.edu/seaice/extent/plot_v2.csv The JAXA Extent graph is now at http://www.ijis.iarc.uaf.edu/seaice/extent/Sea_Ice_Extent_v2_L.png
Toggle Commented Mar 14, 2014 on PIOMAS March 2014 at Arctic Sea Ice
Foolish, Jim? Surely not! "Brave" if you are wrong. And if you are proved correct, the exact opposite of "foolish," whatever that is.
Toggle Commented Mar 12, 2014 on PIOMAS March 2014 at Arctic Sea Ice
Let's tempt fate. Nobody brave enough to call the 2013/4 winter maximum? March 12th? A lot of Arctic heat for the time of year? SIA now 200k below the value two weeks back? Myself, I have a feeling it's there.
Toggle Commented Mar 12, 2014 on PIOMAS March 2014 at Arctic Sea Ice
We have high temperature anomalies in high latitudes. The Arctic Ocean UAH Lower Troposhpere temperature anomay for February is the highest on record, following the January that is now 4th highest. (Graph - usually 2 clicks to "download your attachment".) Less well illustrated (here) is the NOAA SSTs for the start of the year. The actual numbers give, both the Arctic & for the high Arctic, February breaking record temperatures following a January in (now) second/third place.
Toggle Commented Mar 11, 2014 on PIOMAS March 2014 at Arctic Sea Ice
Rutgers Uni snow cover weekly anomalies for June dropped down to a minimum of -5.6m sq km for 2013, ending the year-on-year plunge of the last three years - 2010 -5.1m, 2011 -5.8m, 2012 -6.9m.
So is it just through stormier weather that AGW is increasingly fracturing the Arctic's Sea Ice. This article (hat tip David B. Benson comment @ RealClimate) suggests to me there is another effect at work. It appears higher levels of atmospheric CO2 increase the brittleness of ice. The article talks of glaciers & ice caps being affected to some yet-to-be-determined significance. But Sea Ice too is surely up for it, perhaps with brittleness having more effect out on the oceans.
Toggle Commented Jun 6, 2013 on If this is real... at Arctic Sea Ice
John Christensen. The PIOMAS anomaly dropped about 400 cu km through May with the 1979-2011 anomaly base. The average shown in the PIOMAS volume graph additionally includes 2012 which dropped like a stone through May and so would reduce that 300 cu km figure a bit. And the average 1979-2012 could be a tad 'schematic' in nature. Even so, if you scale the graph with tangents of the average & the 2013 line, the anomaly is increasing. I got a rough figure of 150 cu km from a quick bit of line-drawing. When trying to do such an assessment just visually, your eye will tend to be attracted away from the 'average' curve positioned directly above the 2013 May figures resulting in a comparison partly with the steeper June figure.
Toggle Commented Jun 5, 2013 on PIOMAS June 2013 at Arctic Sea Ice
Rutgers Uni have just updated their NH Snow Cover numbers to week 22. 2013 had just got its nose ahead by mid May (the calculation of the anomaly used on my graph has a small error it seems) but over the last 2 weeks has gone less melty and fallen back. Thus the strong trend for less summer snow seen over the last few years could be taking a year off.
Toggle Commented Jun 4, 2013 on ASI 2013 update 1: a slow start at Arctic Sea Ice
My choice of "four charts that matter"? While atmospheric CO2 is only about half the present anthropogenic forcings, the comment always is that its relative influence will increase with time. Also GHGs appearing through feedback mechanisms (eg melting permafrost)is said will be mostly CO2. So the first chart appears a quite defensible choice. The second, OHC, would perhaps be better if it didn't cut off at 2,000m, but otherwise OHC is the vast majority of the global warming mechanism. The largest warming mechanism after the oceans is now Greenland & Antarctic ice loss which, if combined with the PIOMAS anomaly, would be running at some 1,500 cu km per year or more. I think I would vote for a combined PIOMAS/GRACE-Greenland-Antarctic chart as no 3. I'm not entirely sure about September SIE. While some measure of the destruction of the Northern cryosphere would be good, I am also drawn to the good old Global Surface Temperature Anomaly. It is, after all, a measure of the climate we surface-dwelling humans call home. And when placed below CO2, OHC & ice loss charts, any thought that there is some natural oscillation (as this DocMartyn presents) becomes a trifle risible. And the three preceding charts would surely make plain there is no 'pause'. Indeed, if there is some natural mechanism at work as the hapless DocMartyn would have us believe, it would need to be powered by a lot of energy from somewhere if its going to switch on and off and wobble global average temperatures by 0.2ºC. These days, hiding such a mechanism would take some doing given it would certainly require much more energy than is used annually to melt Arctic Sea Ice. 6+ZJ pa for a decade - thats a lot of energy.
Toggle Commented May 21, 2013 on The Four Charts That Really Matter at Arctic Sea Ice
An interesting Greenland-esque paper within the Skeptical Science weekly listings. J.L. Chen, C.R. Wilson, J.C. Ries, B.D. Tapley Rapid ice melting drives Earth’s pole to the east. The article linked by SkSc is here & the full paper here. I would warn folk not to be carried away by the size of the arrow in the paper's figure 2b. The units 'mas' are milliarc-seconds which are by my reckoning about 30mm long.
John Christensen, I would suggest you are wrong to state that Werner et al 2011 (full text here) "argues that there is a strong connection between changes in ocean currents and Arctic surface cryospheric conditions." They present evidence of a " strengthened Atlantic Water inflow after ca 1860 AD. However, ... (other data) suggest cool surface water conditions until the mid of the 20th century. Changes in all studied proxies indicate warmer temperatures for the past few decades (see Spielhagen et al., 2011) and coincide with positive Atlantic Water temperature anomalies and a retreating sea ice margin for the ca last 100 years (Divine and Dick, 2006; Polyakov et al., 2004, Polyakov et al 2005). The writing in Werner et al 2011 is not without ambiguity (I would say rather too much ambiguity) but to attempt to pile on the significance of AW warming in the Arctic prior to the latter half of the 20th century is surely a further misinterpretation of Werner et al 2011 (and his references to boot). And if you wish to extend the AGW narrative (now truly off topic) to incorporate pre-industrial/non-fossil-fuel-use as "having some impact", it would be good to do more than hint at what level of "some impact" you have in mind.
Toggle Commented Mar 14, 2013 on PIOMAS March 2013 at Arctic Sea Ice
John Christensen. The 'G' in AGW stands for 'global'. The poles climatically act as massive heat sinks, receiving heat from lower latitudes and radiating it out into space. That transfer of heat from lower latitudes into the Arctic can only increase under AGW. Warmer air temperatures & warmer ocean currents are the primary cause of ice loss and rising Arctic temperatures which are amplified by lower albedo due to melted ice and wetter air over the now exposed warming oceans. The Arctic is certainly not the fastest warming region of the planet because of a 40% increase in atmospheric CO2 over the last century-and-a-half.
Toggle Commented Mar 13, 2013 on PIOMAS March 2013 at Arctic Sea Ice
John Christensen. If you analyse global temperature data as you did the 1979 PIOMAS data, you will note than the present warming began before 1979. Indeed, it can be seen from 1976. It may be that 1976 within its time can be considered as 'just another wobble' in a non-warming world, but it was a warming wobble and thus has all that is required to have Arctic-melting abilities. If PIOMAS covered 1976, it would surely show melting on an annual timescale for that year. The Arctic Ice was not doomed because of 1976 or 1979. It is doomed because 1976 has proved to be more than 'just another wobble,' being the start of a world experiencing AGW.
Toggle Commented Mar 13, 2013 on PIOMAS March 2013 at Arctic Sea Ice
Hi NeilT. Decadal-scale CO2 changes show in the smoothed red line on this graph.
Toggle Commented Mar 12, 2013 on The cracks of dawn at Arctic Sea Ice
The spikes in atmospheric CO2 concentrations mentioned above (off topic, mind) are ignorable in the grand scheme of things. However they have their climatical importance inflate by skeptical myth-makers. The biggest climatic wobble is ENSO which a few months later results in a positive wobble in global average temperatures and following later again is a wobble in the rise in CO2. Skeptics love saying this "proves" temperature is the cause of rising CO2 and often graphs are produced to demonstrate their point. There is even the occasional learned paper published saying the same thing, (this one, Humlum et al (2012) even getting peer review, mainly by not putting the effect it investigates into its true climatical context). And it is not put in context because these skeptical messages are all a load of nonsense. This graphic demonstrates it quite well.
Toggle Commented Mar 11, 2013 on The cracks of dawn at Arctic Sea Ice
I can claim with some confidence that Mahlstein & Knutti 2012 use Average Sea Ice Area for the 3 months August to October, not September SIA values. See graph here. (The implications of this difference on its own is perhaps less than other considerations that I reckon together turn their projection of 2°C global temperature rise required for seasonally ice-free Arctic into 1°C. But I feel a bit more nmmber-crunching is required before explaining furhter.)
Toggle Commented Dec 28, 2012 on The real AR5 bombshell at Arctic Sea Ice