By Steve Goddard and Anthony Watts
If you zoom in far enough, most anything looks scary, like this picture of a human head louse.
But when you look at it in the scale of our normal experience, not so much.
Be it lice or ice, the scale of presentation matters.
There is often criticism of cherry picking when it comes to time scales of climate data. In the case of satellite sea ice data presentation, both time scale and vertical scale are magnified. There’s only about 30 years of satellite ice data, whereas Arctic sea ice has been around for millions of years. Vertical scale is magnified to show the smallest fluctuations. Willis Eschenbach made and excellent point about scale when he comparatively demonstrated the scale of ice melt in Greenland in his essay: On Being the Wrong Size. When compared to the bulk volume of ice, the current Greenland melt is statistically insignificant.
There has been a lot of talk about commercial shipping opportunities through the “soon to be ice free” Arctic. These are normally based on highly magnified graphs published by organisations like NSIDC, similar to the one below.
A different view emerges when you take the raw data from NSIDC’s web site and plot it on graphs with a more appropriate vertical scale. Done that way, the downwards trend for April ice is 0.039 million km²/year.
The surprise of scale?
When you calculate the slope, it suggests that April sea ice extent won’t reach zero until the year 2385.
Oh, that can’t be right. How about May? May will be ice free in the year 2404, only 394 years from now. (The US is 234 years old. Copernicus was placed on the “Catholic Forbidden index” 394 years ago.)
June will be ice free in the year 2296.
July will be ice free by the year 2151.
August will be ice free by the year 2103
September will be ice free by the year 2065. (Note that September 2009 was right on the trend line.)
All of the data and plots are available here in this Google online spreadsheet.
September is the minimum and ice starts to freeze up again. No chance of an ice free Arctic in October. But something must be wrong. The experts said that the Arctic would be ice free by 2008, and that it would be ice free by 2013.
“Our projection of 2013 for the removal of ice in summer is not accounting for the last two minima, in 2005 and 2007,” the researcher from the Naval Postgraduate School, Monterey, California, explained to the BBC. “So given that fact, you can argue that may be our projection of 2013 is already too conservative.” “In the end, it will just melt away quite suddenly”
NSIDC director, Dr. Mark Serreze also says this in this 5/20/10 Globe and Mail article:
“We are going to lose the summer sea-ice cover. We can’t go back.”
Dr. Serreze is still on the ‘death spiral’. He hasn’t changed his tune.
While skeptics see cycles, by saying “we can’t go back” Dr. Serreze apparently assumes the linear trend will continue to zero.
You can see from the graphs above how ridiculous those claims are. Even if the current trends continue, there is no reason to expect an ice free Arctic anytime in the next 50 years. And even more interesting to me is the fact that September, 2007 was really not that interesting. It was only 1.5 standard deviations off the trend line, i.e. almost following the 30 year trend.
All of the the main Arctic ice experts underpredicted the 2009 minimum, except for WUWT – which predicted it correctly and early.
—————————————————————-
Science is the belief in the ignorance of the experts
-Richard Feynman
Gail Combs says:
May 25, 2010 at 1:46 am
R. Gates says:
May 24, 2010 at 5:06 pm
“….I certainly don’t dispute the fact of natural climate change of a major amplitude within historic times…i.e. the MWP. My original comment only referred to an ice free arctic. There is no solid evidence to support the notion that the MWP got warm enough to cause the whole of the arctic to be ice free. It would take a satellite image to prove that, as even Eric the Red, or Leif Ericson, or whomever, would have no way of knowing the condition of the ice across the whole of arctic. My point- that an ice free arctic would be unique in human recorded history is valid, and would be disputed by very very few experts, “warmist” or “skeptic”.”
________________________________________________________________________
Gates, these were seafarers and they hunted on the seas, of course they were aware of the sea ice.
____________
Gail, yes, I agree, they were aware of sea ice, but certainly had no way of knowing what the conditions were over the whole of the Arctic.
Few have responded to my proposed questions so here is one source to talk about ideas related to in situ causes of the oft heralded death spiral. Given this information, which variable(s) in the equation provided have changed in the last 100 years? And what was the source of that change?
http://nsidc.org/arcticmet/factors/radiation.html
There is a lot of talk about massive albedo changes if Arctic ice melts away. But just this last winter, as we saw on WUWT many times, most of the northern hemisphere was covered with snow and ice for extended periods, yet there was no dramatic climate shift as a result. Indeed, the albedo change was a RESULT of a climate shift to a colder regime, not a cause of said shift. And since Arctic ice is not in direct sunlight for very long at all, any albedo benefits/banes would be very small.
To me, the fact of not much change due to the massive albedo change this last winter means the climate is not very sensitive to changes within, but is very sensitive to external changes (distance to and output from the sun.)
Pamela Gray says:
May 25, 2010 at 6:43 am
Few have responded to my proposed questions so here is one source to talk about ideas related to in situ causes of the oft heralded death spiral. Given this information, which variable(s) in the equation provided have changed in the last 100 years? And what was the source of that change?
__________________________________________________________________________
Sun=> clouds, Sun=> ocean
The Arctic minimum comes too late in the year to have a significant impact on the earth’s radiation budget. The sun sets in September at the north pole.
This is a very entertaining post as it has brought many “warmests” out to comment. Hard for this hyper denialist to see the point. It seems there is a strain of northern hemispheric bigotry in this inceeasant line of argumentation, pro or con, about arctic sea ice extent. What of the south pole? A think an ET visitor might scratch his head a bit in wondering why there is such focus on one end of the earth.
How does 30 years of data have any meaning at all…to anyone? It seems much “science” can be done without logic or context interfering.
Above all, what does this have to do with AGW? Give me 500 years worth of similar data and maybe then I’d consider such scrutiny to have merit.
Pamela Gray says:
May 25, 2010 at 6:43 am
Rn = So (inverse square law) 1-((interstellar medium dimming)(*GCR-induced aerosols + clouds))
+(Ld (*GCR-induced aerosols + clouds)+ Lu (UHI / Inversion inducing topography))
Everyone if familiar with the Svensmark GCR theory and the upcoming results anticipated from CERN.
Not everyone is aware of Lu (UHI / Inversion inducing topography)) that results from C02 locally forming air inversion.
There are stations that defy UHI effect, and the apparent reason is that local C02 is not the only source of inversion. Topography can act to form a near-permanent inversion, as well as seasonally induced inversion.
This is where the alarmists go off the deep end, assuming that C02 is linear. Direct evidence in Redding and Red Bluff, CA say that it is not. Co2 induced UHI, as well as inversion, has an upper limit. So, once you have an inversion underway, naturally or anthropogenically, adding more gets you nowhere. Pegged out.
Phil. says:
May 24, 2010 at 7:49 pm
Measured downwelling longwave radiation in the vicinity of the N Pole from April to September is ~300W/m^2.
Do you have a reference for that data? It sounds quite interesting.
stevengoddard says:
May 25, 2010 at 8:44 am
The Arctic minimum comes too late in the year to have a significant impact on the earth’s radiation budget. The sun sets in September at the north pole.
___________________
Steve, there are more effects that insolation on open arctic ocean to consider. There is the outgoing LW radiation from the open arctic water that can have effects on the temperatures of the surrounding land. I posted this link yesterday related to how loss of Arctic Sea ice can cause an amplification in warming on land:
http://www.the-cryosphere.net/3/11/2009/tc-3-11-2009.pdf
I’m a bit confused about your position on this. It seems from the post yesterday that you agree that the Arctic will be ice free in the summer this century. Is that your position?
R. Gates
The net radiation budget from the Arctic is negative. It loses more LW than it absorbs SW.
http://earthobservatory.nasa.gov/Features/EnergyBalance/images/ceres_net_radiation_200809.jpg
http://earthobservatory.nasa.gov/Features/EnergyBalance/page3.php
stevengoddard says:
May 25, 2010 at 8:44 am
At 85 degrees north, the sun does not go fully below the horizon at all till September the 14th. At the equinox, there are 12hrs day, and 12hrs night, like every where else on the planet. It is not until Oct 5th at this lattitude, that the Sun remains below the horizon all day.
Ulric Lyons
The critical angle of a water/air boundary is 48 degrees. Because the surface of the ocean is not completely smooth, you still get some absorption down to lower angles. By September, there is almost no solar energy being absorbed in the Arctic ocean.
@stevengoddard says:
May 25, 2010 at 12:59 pm
We are talking ice, not water. The Sun stops shining on it early October, which is when it stops it melt, and starts to expand again. It should be at its minimum in September. You try leaving some ice out in front of the Sun when it is 5 degrees above the horizon, I think you will find it still melts.
Why does IARC-JAXA show sea-ice at 11,429,375 km2 while http://nsidc.org/data/seaice_index/images/daily_images/N_stddev_timeseries.png clearly shows it above 12,000,000? Is this a graphing error or what?
“”” stevengoddard says:
May 25, 2010 at 12:59 pm
Ulric Lyons
The critical angle of a water/air boundary is 48 degrees. “””
Steve; “critical angle” is a consequence of Snell’s law of refraction; nemely:-
n1.sin(I1) = n2.sin (I2) where n is the refractive index of the medium, and (I) is the angle of incidence of the ray (measured relative to the normal to the surface.)
For the air/water interface, n1 is 1.000 (essentially) and n2 is 1.333
So for light incident on the water at 90 degrees (grazing incidence) we would have:-
1.000 sin (90) = 1.333 sin(I) ; yielding I = 48.6 deg
So even for incidence angles up to 90 degrees there still is refraction of light into the water; but as the above shows, it never enters the water at any angle greater than 48.6 degrees; which happens to be the magnitude of the critical angle.
For a fish or a scuba diver under the (flat) surface; looking up; he would see the entire hemisphere of the sky contained within a circel having an agular radius of 48.6 degrees.
By the principle of reversibility (of the rays) we can then say that for light rays proceeding from the water out into the air; there is no solution for I2 (in air) for any value of I1 (in water) greater than 48.6 degrees; which is the critical angle concept. For any ray, in the water striking the surface at an incidence angle greater that Ic (48.6), the surface behaves as a perfect mirror, giving 100% reflectance in accordance with the laws of reflection (which can also be handled as a special case of refraction by simply setting the refractive index in the first medium (water) be n1, and the index following “refraction” to be -n1, which yields:-
I2 = -I1
The point is that the critical angle effect only occurs for refraction out of the higher index medium; in this case water.
The Brewster angle is given by Tan(B) = (n2/n1) whereas the critical angle is given by Sin (Ic) = (n2/n1); which has no solution for n2>n1
At the Brewster angle the reflected and refracted rays are perpendicular to each other, and the light component polarised with the electric vector in the plane of incidence being suppressed; so only the polarisation component perpendicular to the plane of incidence gets reflected. The plane of incidence contains the incident, refracted, and reflected rays, as well as the normal to the surface.
At the Brewster angle; which is 53.1 degrees for light incident from the air side or 36.9 degrees for light incident from water into air, the reflection coefficient of the surviving polarisation component is roughly doubled from its normal incidence value.
At normal incidence; from either side, the reflection coefficient is ((n1-n2)/(n1+n2))^2 which for water works out to 0.02 (2%)
As the angle of incidence increases from zero up to (B), the reflection coefficient of the in plane component falls to zero, while the perpendicular component rises to about double. So the total reflectance remains almost constant at it normal value, up to the Brewster angle, and beyond there it rises rapidly towards unity. The reflected light beyond the Brewster angle is significantly linear polarised with the bulk of the energy in the perpendicular component.
It is the effect of the rapidly increasing reflectance at grazing incidence, that limits how much sunlight can enter the water surface in th earctic; not the Critical angle which only acts from water into air.
For full pedantic accuracy for those who need a PhD thesis for every little exercise in thinking; you have to use the full Fresnel Polarised reflection and transmission equations; which I am not even going to type out here; because if you are that fussy, then you also have to drag out the full complex index data for the media; and that gets less than instructive.
Steve; Critical angle does not restrict sunlight from entering the Arctic ocean surface; but increased reflectance does; at near grazing angles.
“”” Phil. says:
May 24, 2010 at 7:49 pm
Measured downwelling longwave radiation in the vicinity of the N Pole from April to September is ~300W/m^2. “””
Phil,
Is that a clear sky value of down IR or is that with cloud cover ?
George
stevengoddard says:
May 25, 2010 at 12:59 pm
Ulric Lyons
The critical angle of a water/air boundary is 48 degrees. Because the surface of the ocean is not completely smooth, you still get some absorption down to lower angles. By September, there is almost no solar energy being absorbed in the Arctic ocean.
But for an air/water interface there is no ‘critical’ angle, so your statement is not accurate.
Re: stevengoddard on May 25, 2010 at 12:59 pm
Steve, you’re suffering the same bit of confusion I had a short while ago until I brushed up on my optics knowledge. The critical angle applies when considering a light ray going from a medium with a higher index of refraction to one with a lower index, in this case a light ray from the water to air. At greater than about 48 degrees from the normal you would get total internal reflection, the ray couldn’t leave the water. For light going air to water it doesn’t apply.
We’re used to seeing light bounced off of water at small angles, but part of what we’re seeing is polarized light, one component tends to get reflected (strongly polarized) while the other is transmitted (weakly polarized). Here’s a relevant article on Brewster’s angle.
This in several ways is a nitpick as very little light is going to get transmitted in any case at those angles, nearly all of it gets reflected. But it’s a scientifically accurate nitpick. Of course I fully expect you to correct me if I am in error about the optics or what you were actually saying. Actually I hope you do, as I wanted to kick myself for forgetting such details even if those university optics courses were a few decades in the past. 😉
Dave Wendt says:
May 25, 2010 at 11:31 am
Phil. says:
May 24, 2010 at 7:49 pm
Measured downwelling longwave radiation in the vicinity of the N Pole from April to September is ~300W/m^2.
Do you have a reference for that data? It sounds quite interesting.
Here for example: http://www.arctic.noaa.gov/np2008/gallery_np_weatherdata.html#weather
Re: kadaka (KD Knoebel) on May 25, 2010 at 2:50 pm
(currently awaiting moderation)
Ah heck, while I was writing a reply, George E. Smith wrote a rebuttal article.
Oh well, so it goes. At least mine is a faster read. 🙂
kadaka
You are correct. This graph shows the effect I was describing. When the sun is five degrees above the horizon, 60% of the light is reflected. That light is already greatly diminished by the low angle spread out across the surface sin(5) = 0.087 and further diminished by taking a long path through the atmosphere. i.e almost no light enters the water.
http://en.wikipedia.org/wiki/File:Water_reflectivity.jpg
So, which one of these parameters has changed folks? And changed in a trended way? And in a way significant enough to produce the increased melt? Is there more CO2 up there? Are there more clouds up there? Less clouds? Did we get warmer ocean currents from somewhere? Is the change in the perimeter to open water changing the net imbalance? Sounds like we are still in net negative imbalance so I ask again, what has measurably and significantly changed in the equation to cause the melt trend?
If you think it is CO2 related, you have to show increased re-radiation in the air or oceans (either in situ or brought there) that increased air or ocean temps above and/or below the ice. Has that happened? As far as the Arctic data is showing, ocean temps are not outside the normal range and air temps are not outside the normal range and match well with weather pattern variations. And we are still in a negative balance up there.
What has changed folks, what has changed. Don’t tell me albedo unless you have data.
So what? If it’s been cooling since 2002, we’ve past or are cresting the peak (maybe). And maybe there’s something wrong with the models, which didn’t predict this deviation from the CO2 “forcing.”
schweinsgruber
It was a lot warmer in the Triassic, so I think it is safe to say that we are on a long term cooling trend. Of course it was a lot cooler 20,000 years ago, so it is also safe to say that we are on a long term warming trend.
stevengoddard says:
May 25, 2010 at 12:20 pm
The net radiation budget from the Arctic is negative. It loses more LW than it absorbs SW.
Then tallbloke was correct when he envisioned that transport of heat energy to the Arctic is going to result in heat/energy loss for the Planet. Now we are right back to the Meridonial Flows of the last 3 years. The Climate is blowing heat out the hole in the roof. It would be far better for this not to occur, as the heat isn’t going to where it will do the most good: The Temperate Zones. Doesn’t mean a thing for the Arctic, as it can refreeze with the greatest of ease… once the supply is exhausted or stops.
The Antarctic is doing quite well these days, being .6M km^2 above normal, while the Arctic is 1.0M km^2 below normal ice extent.