Guest Post by Willis Eschenbach
There’s a new study in PNAS, entitled “Observational determination of albedo decrease caused by vanishing Arctic sea ice” by Pistone et al. Let me start by registering a huge protest against the title. The sea ice is varying, it isn’t “vanishing”, that’s just alarmist rhetoric that has no place in science.
In any case, here’s their figure 4B, showing the decrease in albedo from the “vanishing” sea ice:
Figure 1. Graph from Pistone2014 showing CERES albedo data (green, solid line) for the ocean areas of the Arctic.
The authors say:
Using the relationship between SSM/I and CERES measurements to extend the albedo record back in time, we find that during 1979–2011 the Arctic darkened sufficiently to cause an increase in solar energy input into the Arctic Ocean region of 6.4 ± 0.9 W/m2, equivalent to an increase of 0.21 ± 0.03 W/m2 averaged over the globe. This implies that the albedo forcing due solely to changes in Arctic sea ice has been 25% as large globally as the direct radiative forcing from increased carbon dioxide concentrations, which is estimated to be 0.8 W/m2 between 1979 and 2011.
The present study shows that the planetary darkening effect of the vanishing sea ice represents a substantial climate forcing that is not offset by cloud albedo feedbacks and other processes. Together, these findings provide direct observational validation of the hypothesis of a positive feedback between sea ice cover, planetary albedo, and global warming.
So … how are they going about making that case?
Let me start by saying that looking at albedo as they are doing is a very roundabout and inaccurate way of handling the data. The CERES dataset doesn’t have an “albedo” dataset. Instead, they have a dataset for downwelling solar, and another dataset for upwelling solar. The problem is that when the numbers get very small, the values of the calculated albedos get more and more inaccurate. Albedo is reflected solar divided by downwelling solar. So when you get down to where there’s almost no sunshine, you can get things like a gridcell that averages 0.2 W/m2 of incoming sunlight over some month, and reflects 0.4 W/m2 … giving us an impossible albedo of 2.0 …
It’s not clear how Pistone et al. have handled this issue. The way I work around the problem is to calculate the average upwelling reflected sunlight for the Arctic ocean area, and divide that by the average downwelling sunlight for the Arctic ocean area. This gives me an overall average albedo. I get slightly different numbers from theirs, and I am unable to replicate their results. However, I do get about the same trend that they get over the period, a decrease in the albedo of about 1.5% per decade. However, I don’t particularly trust those albedo numbers, averages of ratios make me nervous.
For this reason, I use a different and simpler measure, one which Pistone et al. mention and quantify as well. This is the actual amount of sunlight that makes it into the climate system. The authors call this the “total solar energy input”, and I will follow the practice. And qualitatively, my results agree with theirs—the amount of sunlight absorbed by the arctic has indeed increased over the period of the CERES data, 2000-2013. Figure 2 shows both the clear-sky and the all-sky arctic total energy input:
Figure 2. Increase in solar energy input to the Arctic ocean areas, 2000-2012. Clear sky in black, all sky in red. Units are area-weighted watts/m2.
In addition to the overall trend in all sky solar input (green line), you can see the peak in energy input in 2007, with the high solar input corresponding to very low ice areas. Overall, Figure 2 shows an even greater increase in energy input than Pistone2014 have estimated over the entire period. They report an increase in Arctic solar energy input over the ocean of 0.21 W/m2 over 32 years … and the CERES data shows an increase of 0.3 W/m2 per decade.
So we’ve established that their first claim, of increasing solar energy input to the Arctic ocean area 2000-2012, is true, and perhaps even underestimated. And this is quite reasonable, since we know the sea ice has decreased over the period … but what about their second claim? As you may recall, this was (emphasis mine):
The present study shows that the planetary darkening effect of the vanishing sea ice represents a substantial climate forcing that is not offset by cloud albedo feedbacks and other processes. Together, these findings provide direct observational validation of the hypothesis of a positive feedback between sea ice cover, planetary albedo, and global warming.
The CERES data agrees that the increase in solar energy input from reduced ice cover is not counteracted by Arctic clouds … nor would I have expected it to be counteracted by clouds in the Arctic. As I have discussed, well, more than once, the main climate control system is in the tropics. So if this increase in absorbed energy were counteracted by clouds, my hypothesis is that it would happen be in the tropics. I’ll return to this in a moment.
First, however, they’ve claimed that their results establish the existence of “a positive feedback between sea ice cover [and] planetary albedo”. Since the planetary albedo controls the total solar energy input to the globe, let’s take a look at the same data as Figure 2, total solar energy input, but this time for the entire planet …
Figure 3. Available solar energy at the top of atmosphere (red) and total solar energy input to the globe (blue), 2000-2012. Units are area-weighted watts/m2.
So their claim of increased solar energy input to the Arctic from reduced sea ice is true … but their claim that there is “a positive feedback between sea ice cover [and] planetary albedo” is falsified by the CERES data. The total solar energy input (blue line above), and thus the planetary albedo, is amazingly stable over the time period. There is no feedback at all from the changes in the ice.
To illustrate the stability, Figure 4 shows a breakdown of the total solar input data (blue line above). It’s divided into panels that from top to bottom show the data itself, the seasonal pattern, the trend, and the residuals of the global solar energy input:
Figure 4. Decomposition of the solar energy input signal into trend, seasonal, and residual components. Red scale bars on the right indicate the relative scale of the individual panel. Units are area-adjusted W/m2.
I’ve written before about the amazing stability of the climate system. This is another example. In the past people have objected that the system is forced to be stable, because over time, energy out must generally equal energy in.
But the global solar energy input, the amount of the available solar energy that actually makes it into the climate system, is under no such constraint. There is nothing that it must balance to. Solar energy input is a function of the albedo, which is determined by clouds, snow, ice, vegetation, and wind, and all of these are constantly varying in all parts of the planet … and despite that, the swings of the trend are no greater than ±0.3 w/m2 over the period. The maximum monthly deviation from the seasonal average is a mere one W/m2, and the standard deviation of the residuals (data minus seasonal) is half a watt/m2.
So … how does it happen that we have a strong increase in solar energy input in the Arctic, but the global energy input stays the same?
Well … as I mentioned above, the tropics. Over the period 2000-2012, during which the Arctic received increased solar energy input, here’s what’s happened in the tropics:
Figure 5. Total solar energy input, all skies, tropics. Units are area-adjusted W/m2
As I hypothesized, the control is happening in the tropics. Pistone et al. note that the Arctic solar input is going up because of decreased sea ice … but they did not notice that at the same time, the tropical solar input is going down because of increased clouds. And the net sum of all of the changes, of more energy being absorbed in the extra-tropical areas and less energy being absorbed in the tropics, is … well … no change at all for the globe. It all averages out perfectly, with little change in either the monthly, annual or decadal data.
Coincidence? Hardly.
This is about as neat a demonstration as I can imagine in support of my hypothesis that the system is not ruled by the level of the forcings—instead, it is regulated by a system of interlocking emergent climate phenomena. A number of these phenomena operate in the tropics, and they have a curious property—the warmer the planet gets, the more that they cut down on the incoming solar energy.
So at the end of the day, we find that the claim of the authors that increased solar input to the Arctic is connected to the planetary albedo to be true … except that it is true in exactly the opposite of the direction that they claimed. When more energy is absorbed in the Arctic, less energy is absorbed elsewhere.
In closing, I want to highlight what it was that got me interested in climate science to begin with. I wasn’t interested in finding out why the global temperature had changed by something like ± 0.3°C over the 20th century.
Instead, I was interested in finding out why the global temperature had only changed by ± 0.3°C over the 20th century. I was amazed by the stability of the system, not the fact that it had varied slightly. So let me close with a graph showing the total global solar input residuals, what remains after the seasonal cycle in total solar input is removed.
Figure 5. Residual total solar input after the seasonal cycle is removed. Dotted lines show the inter-quartile range. Smooth curve is the loess trend line.
The monthly deviation from the seasonal cycle is tiny. Half the months are within a third of a W/m2 of the seasonal average … a third of a watt, to me that’s simply amazing.
Now, you might disagree with my hypothesis that the planet is thermoregulated by emergent climate phenomena such as thunderstorms, El Nino, and the PDO.
But the stability shown in the above graphs surely argues strongly for the existence of some kind of regulatory system …
My regards, as usual to everyone.
w.
AVISO: If you disagree with what I or anyone says, please quote the exact words you disagree with. It allows everyone to understand exactly what you are objecting to.
DATA AND CODE: You’ll need the CERES data (227 Mb) , the CERES surface data (117 Mb) and two support files (CERES Setup.R and CERES Functions.R) in your R workspace. The code is Arctic Albedo.R, it should be turnkey.
[UPDATE]
Well, y’all will find this funny, I assume … following up on the question of the net effect of the loss of the sea ice that came up below in the comments, I decided to see what was happening with the upwelling longwave. We’ve established that the loss of the ice increases the total solar energy input … but what about the energy loss via longwave? (Yr. humble author slaps forehead for not thinking of this sooner …)
As you can see, the change in solar energy input is more than offset by increased losses … so the net effect of the melting sea ice is a net energy loss of 0.05 W/m2 per decade.
Note again the stability over time. Note also that this part of the system is not constrained by any need for solar input and longwave output to be stable, or to have the configuration they have. The average solar input is 30 W/m2, and the average longwave loss to space is 63 W/m2 … and despite the marked changes in ice cover over the period, they’ve only changed about 1% per decade over the period …
Gotta love the climate, always more surprises …
w.
[UPDATE II]
Some folks have said that there is a problem with my area-weighting, so let me explain exactly what I did.
The data exists in 180 latitude bands. The center of the bands start at -89/5° (south) and end up at 89.5° (north). To area-weight the data, we want to adjust the results for each gridcell by the area.
What we want to do is adjust the results to give what you would get if they had the size of the average gridcell. Now the area is proportional to the cosine of the mid-latitude. So what we do is multiply each gridcell result by
area of the gridcell / area of the average gridcell
This give each gridcell the value it would have if it were of average size. The effect of tiny gridcells is reduced, and the effect of large gridcells is increased.
Now, what is the average cell size? Well, if we integrate Cos(x) from zero to pi/2, we get 1. So the average gridcell size is 1/(pi/2) = 2/pi ≈ 0.637.
As a result, the weighting factor by which we multiply the gridcell value is, as you recall:
area of the gridcell / area of the average gridcell
which is equal to
cosine of the gridcell midlatitude / 0.637
Once you’ve multiplied the data by those weighting factors, you can compare them directly, as they are all adjusted to the average gridcell size.
The way to test if you’ve done this correctly is to see if the plain vanilla average of the newly-weighted dataset is correct. For example, see the average available solar (~340 W/m2) and solar input (~240 W/m2) values in Figure 3. They are simple averages of weighted data.
Note that there are two ways to do the weighting.
The first is to do all calculations (trends, etc) using the unadjusted variables. Then to get an average, you use what is called an “weighted mean”, which weights the data on the basis of gridcell area as it calculates the average.
The other way to do it is the way I described above, which converts all of the data to what an average sized gridcell would show. Once you’ve done that, you no longer need to do an area-weighted average, because the data itself is weighted. This means that you can use a normal average, and compare things like trends directly.
So … what I do to check my work is to compare the normal mean of the area-weighted data, with the weighted mean of the original data. They should be the same, and that is the case in this analysis.
Finally, an area-weighted mean uses different weights, where the sum of all of the weights is 1. This allows you to calculate the weighted mean as the sum of the product of the data and the weights. These weights are different than the weights I used to area-weight the data itself. These weights which do not sum to 1. However, the end result is the same.
Amatør1 says:
”Why worry about how much sunlight is entering the system, when the backradiation is twice as intense?”
Yea, that’s why I wear GHE block instead of sun block; sunburn just isn’t anything to worry about anymore. Kids just aren’t going to know what sunburn is in a few years. etc. (/sarc)
You’re not comparing NET heat fluxes; from the guestimate you linked the NET IR is 396-333=63 up, the 333 back-radiation (GHE) merely slows the radiant cooling from the surface which without it would be losing heat radiantly at 396 W/m2, but with it at only 63 W/m2 on average. Doubling CO2 is estimated to increase this by almost 4 W/m2 so the net heat loss would supposedly go down to about 59 assuming everything else remained the same. (sarc) Really scary! (/sarc)
Also you’re comparing energy at different wavelengths. UV, Vis, and IR have different capabilities regardless of intensity.
RACookPE1978 says:
“Ocean Albedo behaves differently for direct radiation and diffuse radation.
Diffuse radiation: Does not vary with wind speed, water turbidity, algae or plant levels, or solar elevations angles. Usually, open ocean albedo is = 0.065
Direct radiation: Varies strongly (from 0.035 to 0.45) with solar elevation angles.
At any given solar elevation angle, ocean albedo will decrease (more energy can be absorbed) as wind speed increases from 0. Usually, higher wind correspond to increased cloud cover also.”
[Covers] what I said about direct [reflection] and more.
Wave [height] (wind) is a key factor for open water but probably does not apply that much to exposed leads in the ice and shallow melt ponds.
Once more we see psuedo science produced on demand for money, and for the benefit of the agenda to eliminate fossil fuel use. All part of the plan to dumb down the population .
milodonharlani says: @ur momisugly February 18, 2014 at 8:57 am
Leif thinks that Bond Cycles are fictitious if not fantastic….
>>>>>>>>>>>>>>>>>>>>
First off Leif is a solar physicist and not a geologist.
Second NASA has a page on the Dansgaard-Oeschger Oscillations and states they do not know what causes them. NASA also has a link to the papers written by Bond. D-O events are the same as Bond events but D-O occur during the cold periods and therefore are much easier to spot.
Third there is a paper possibly linking D-O events to lunar tide north-south movement. The 1,800-year oceanic tidal cycle: A possible cause of rapid climate change
Also even Leif agrees that due to the Milancovitch cycles we are looking at subdued solar forcing for thousands of years. One paper puts the Holocene Optimum as having 9% more solar insolation for 21 June at 65◦ N.
The paper I link to above, “Can we predict the duration of an interglacial?” contained the solar insolation for 21 June at 65◦ N and CO2 for termination of several interglacials.
Current values are insolation = 479 W m−2 and CO2 = 390 ppmv.
MIS 7e – insolation = 463 W m−2, CO2 = 256 ppmv
MIS 11c – insolation = 466 W m−2, CO2 = 259-265 ppmv
MIS 13a – insolation = 500 W m−2, CO2 = 225 ppmv
MIS 15a – insolation = 480 W m−2, CO2 = 240 ppmv
MIS 17 – insolation = 477 W m−2, CO2 = 240 ppmv
Despite what Englebeen is trying to push, Zbigniew Jaworowski showed that early ice core measurement gave much higher reading especially if the CO2 is extracted from the whole ice sample and not just the air bubble. So that makes those CO2 reading rather suspect.
Are we headed into glaciation? Heck if I know but given the subdued solar insolation at the possible tail end of the Holocene, the focus of science ONLY on Global Warming with the stated aim of destroying our present technological society strikes me as mass suicide at least for most of the peasants. This is especially true when the USA got rid of the strategic grain reserves in 1996 and ran the the grain silos dry by 2008. Now the USA is burning any excess grain as bio-fuel.
In other words the current US policies put us in the same position that the Little Ice Age peasants were in except there are more of us and we are completely dependent on a fossil fuel ‘Just-in-Time’ delivery system for our food.
The 1974 CIA report: “A Study of Climatological Research as it Pertains to Intelligence Problems” certainly doesn’t give me any faith that our political leaders are concerned with the peasants survival either.
Holdren and the other Malthusians from Stanford University are not alone. The US government has been behind them since BEFORE the book Human Ecology: Problems and Solutions (1973) was published recommending the USA be de-developed. The book just echoed the real thoughts of the US government of that time. Given Holdren is Obama’s Science Czar and the Malthusian drivel is still coming out of Stanford (Leif’s Univ) I do not see that the actual mindset in DC has changed.
Those observation gives me nightmares especially since we see the US government behind the striping of assets of the USA including literally packing up and shipping our factories and technology overseas.
Dang forgot the slash to close the bold on the last insolation reading. That is what I get for rushing …
Billy Liar says:
February 18, 2014 at 8:16 am
I would argue that for the last 2.6Ma the climate has been demonstrably bistable and not very tightly regulated in between.
==============================
I would also model the advance and retreat of continental ice as an oscillator inclusive of its attendant damping coefficients and feedback loops.
One thing seems a little odd with all this “observable” evidence of positive feedbacks is that with the massive melt and all time lowest arctic ice extent in “recorded history”, that global temps have been stable to the last 15 years and show cooling since 2005.
Looks like they must have overlooked something…. out-going LW neg. f/b perhaps??
thanks again for another good job.
Ratios of means vs means of ratios: what you really want is the full distribution of the ratios, but with low numbers and high measurement errors, the problem that you describe largely vitiates their use. The ratios of means are more stable, but are a biased estimate of the mean of the ratios. This is not a dispute of your choice; I am glad you described it as you did.
Alec Rawls says:
February 18, 2014 at 7:41 am
Once Antarctic sea ice is taken into account there has been essentially no change in GLOBAL sea ice since 2000 (or 1979), yielding no net polar albedo effect.
————————
The additional Antarctic sea ice is much closer to the equator, therefore, there is a significant positive global albedo increase.
I think somebody here (in comments on WUWUT) has already estimated the effect and the increase in Antarctica was much larger than the decrease in the Arctic.
The study is obviously biased, when they do not use precise language, making clear, that they are only looking at a misleading part of the whole story, or even making false claims such as about “planetary darkening”:
“The present study shows that the planetary darkening effect of the vanishing sea ice represents a substantial climate forcing that is not offset by cloud albedo feedbacks and other processes.”
Raises hand to ask question-
Why is it, that no one ever just points out that ice sheets melting between glacial periods is NATURAL and PRECEDENTED, and thus EXPECTED? I mean, yeah…they melt. They “vary”. Naturally.
I mean, it’s fine to argue over why and how and to what extent their size changes. Basic curiosity. But they seem to want to imply that at some point Earth reached a “static” point where none of the things that have happened, repeatedly, in the past were ever going to happen again. Thus-what is happening today is scarey, abnormal, disastrous.
Seems that sometimes the simplest way to rebutt any alarm such papers cause, would be to just add something like “Just like it has in the past” to their titles.
Willis,
I thought you were retiring from climate but am delighted to observe that your contributions seem to be going up.
You’re right, it’s amazing that the global variation is so small considering all the interacting causes and effects going on constantly and at the same time. Some of us would consider it as evidence of an overall design than we can barely grasp; I guess others would perhaps see it as the goldilocks effect. Either way, it’s just another of those things that makes you go “wow!” when you see it. Thank you.
“Given a concentration of CO2 and radiation field (watts/m^2) what is the rate that CO2 converts one form of radiation to another?”
dear god.
Willis
You might want to do an analysis of the position in the Antarctic.
We all know the sea ice has been increasing at a significant rate for many years.
However, what a lot of people are not aware of, is that the albedo of Antarctic sea ice is much larger than Arctic sea ice for the equivalent area and extent
This is because due to the nature of the melting Arctic ice,,mainly from above in summer and Antarctic ice, mainly from below. This means snow cover disappears on Arctic ice and is retained on Antarctic ice and snow covered ice has a much higher albedo compared to most non-snow covered ice. The difference can be as big as twice as much.
This has been confirmed by an expedition taking actual measurements in the Antarctic.
Here is a peer reviewed paper giving the figures and you might find it amusing to turn you enquiring mind to the issue.
http://www.atmos.washington.edu/~sgw/PAPERS/2005_seaice_albedo.pdf
Regards
Alan
”
Steven Mosher says:
February 18, 2014 at 1:00 pm
“Given a concentration of CO2 and radiation field (watts/m^2) what is the rate that CO2 converts one form of radiation to another?”
dear god.
”
From Box o Rocks
Box,
Co2 is going to absorb and emit radiation of various wavelengths based upon fundamental factors including temperature. Pressure broadens these wavelengths. The only conversion happening is going to be converting from thermal energy to radiated energy and converting from radiated absorbed energy to thermal energy. The gas must be hot enough to have the energy state populated in order that there is some radiation occurring from them. It depends upon also how much time between collisions where a higher state can be ‘disarmed’ into a lower state by thermal transfer of energy rather than radiated transfer. Unlike emission which requires the gas be hot enough to have a population of the particular state, absorption depends very little on temperature so it can absorb a photon even when cool. In short, co2 absorbs some energy at specific wavelengths and if the temperature of the energy going through is at the same value as the gas, it will appear transparent – absorbing the same as it emits. If hotter, it will produce emission lines. If cooler, there will be absorption lines. That’s about the only stuff that is fairly well known and considered – sort of. Unfortunately, the presence of clouds blocking the IR throw a monkey wrench into the basic theory and so do a few other things – like albedo. It’s sorta like the medical concept that you can take a cancer tumor out of the body and see how much of what chemo agent will kill it dead but it’s a totally different situation to think that this same agent and concentration will rid the patient of all of cancer (even assuming the concentration is not fatal to the patient). There’s just too many other factors that will come into play due to the complexity of the human body.
Tru tty
The Goldilocks argument
Like RACook etc says above. Antarctic sea ice, not to mention continental or land ice, is more important than Arctic Sea Ice because it extends much farther from the pole and hence angle of solar incidence is higher.
Every time that the Warmists talk about Arctic Sea Ice, one ought to say that the ultimate issue is “global” climate change, and therefore the relevant measurement is “global” sea ice coverage.
cba says:
February 18, 2014 at 2:01 pm
So you are saying that we can NOT do an energy balance on a CO2 molecule wrt to radiation as the molecule absorbs energy, and then at some time later re-emits said energy?
Oh my.
OH MY –
meant to say –
we can NOT do an energy balance…
[Fixed. -w.]
R. Barrow says:
February 18, 2014 at 2:40 am
The tropics are constantly exporting energy to the poles. This is driven inter alia by the tropical/arctic temperature difference. When/if the poles warm, that transport slows dow. As a result, the tropics immediately warm up, since the export of energy is slowed …
There are other mechanisms, as others have mentioned, but I think that is a main communication method …
w.
Ed_B says:
February 18, 2014 at 3:38 am
Indeed. I see it as one of my main communication goals, to spread that idea as widely as possible.
w.
gopal panicker says:
February 18, 2014 at 3:59 am
Not true, I’m afraid. People think it’s like paint, that after it’s painted nothing more is achieved by an additional coat.
But CO2 works differently. The issue is how many times your average photon of escaping longwave gets re-absorbed before leaving the atmosphere.
As a result, even if the IR absorption is “saturate”, more CO2 will still increase the GHE.
w.
Mosher writes “A required cross check would be to look at a validated dataset for global albedo from 1981 to present. GLASS is one of two that exist.”
It looks to me like the GLASS abedo product deals with land based albedo only. How would you propose to cross check land based albedo with global abedo, Steve?
Bloke down the pub says:
February 18, 2014 at 4:05 am
charles nelson says:
February 18, 2014 at 4:10 am
You both point to a complex polar issue, which is the interaction of not much incoming sunshine, low angles of incidence, the albedo of ice vs. water, heat transfer from the tropics, and the insulative value of ice versus water. I’ve seen estimates that overall heat loss goes up when the ice melts … and I’ve seen estimates of the opposite.
It strikes me while writing this that we might have enough data to answer the question. Sounds like a good project, and what I need is the gridded map of ice coverage on a 1° grid. With that plus the CERES data, we should be able to answer the question … always more things on my list.
w.
Well, y’all will find this funny, I assume … following up on the question of the net effect of the loss of the sea ice I mentioned above, I decided to see what was happening with the upwelling longwave. We’ve established that the loss of the ice increases the total solar energy input … but what about the energy loss via longwave? (Yr. humble author slaps forehead for not thinking of this sooner …)
As you can see, the change in solar energy input is more than offset by increased losses … so the net effect of the melting sea ice is a net energy loss of 0.05 W/m2 per decade ..
Gotta love the climate, always more surprises … I’ll put this as an update in the head post …
w.