Guest Post by Willis Eschenbach
I got to thinking about snow the other day. It was occasioned by my look at the correlation (both positive and negative) of temperature and albedo. Albedo is a measure of how much sunlight is reflected from the clouds and the surface. The greater the albedo, the more sunlight is reflected. Here’s the graph that set me pondering:
Figure 1. Correlation between surface temperature and albedo. Negative correlation (blue and green) means the albedo goes down (less reflected sunlight) as the surface warms. Positive correlation (red and orange) means the albedo goes up (more reflection) as the surface warms. Gray line shows zero value.
In the red and orange areas, which are mainly in the tropics, the albedo goes up as temperatures rise. This is generally because clouds form as temperatures rise, reflecting more sunlight and cooling the earth. In the blue and green areas, on the other hand, the albedo goes down as temperatures rise. Over the extratropical land, much of this change is from snow and ice. As the land warms, snow melts and the albedo goes down. And as the land cools, snow falls and the albedo goes up. This is a positive feedback, with warming leading to increased solar energy, and cooling leading to less solar energy.
One thing that is highlighted by this map is that the positive feedback from the changes in sea ice are much smaller than the feedback from the changes in snow and ice on land, for several reasons.
The first one is the small area of the sea ice variations. Note that the feedback is only in the areas that are seasonally uncovered and covered by sea ice—permanently ice-covered areas don’t have much albedo change. Net annual variation in Arctic sea ice is about ± 5 million square kilometres. This is only about 1% of the area of the globe.
Another reason the changes on land are larger is that when snow melts, it exposes soil and plants, both of which have low albedos. But when sea ice melts, it reveals ocean … and the albedo of the ocean at low sun angles is already pretty high. As a result, the melting of the ice doesn’t change the albedo as much as the melting of the snow.
Another reason the land varies more is that snow extends much closer to the equator than sea ice. As a result, the sun rises much higher over snow than sea ice, and thus the snow intercepts more sunlight than the same area of ice up near the poles.
Another reason is that as you can see from Figure 1, the negative correlation of the albedo and temperature is greater over northern lands than northern oceans.
All of this has made the snow-covered areas of the northern hemisphere the main suspects in the onset of the ice ages. The generally accepted theory is that the so-called “Milankovitch” variations in the earth’s orbit change the amount of sunshine hitting the northern hemisphere. When the northern hemisphere summer sunshine gets weak enough, the snow on the northern land doesn’t melt back as far. This residual snow reflects more sunlight, which leads to cooler temperatures, which leads to more snow, which leads to more reflected energy … I’m sure you can see the end of this story, glaciers a mile thick covering Chicago.
Now, people seem to have a strange need to believe in some kind of existential threat hanging over our heads. There appears to be a desire to worry about something, as long as it is dire and a couple of decades away. In the past we’ve filled this need by worrying about the “population bomb”, or the “ecological footprint”, or the dreaded arrival of “peak oil”. Nowadays, it seems like “global warming” is taking over the role of the scourge du jour.
Me, I prefer to only concern myself with real possibilities of real harm. We’ve seen a couple of degrees warming since the Little Ice Age, and overall the effects have been beneficial to humans, plants and animals. I have no concern about the fabled Thermageddon of a couple degrees more warming—the effects are not grave, will likely be beneficial, and I have strong doubts that it will happen this century.
Another ice age, on the other hand, seems to be both inevitable and very destructive. And to raise the stakes, near as scientists can tell the next ice age either due or overdue … this is already the longest of the “interglacials”, the historical periods in between the ice ages.
So I would suggest that we keep a fairly close watch on the snow cover of the northern hemisphere. Because when the apparently inevitable ice age comes ’round again, it seems to me that the first sign will be an increase in the snow cover in North America and Eurasia.
Fortunately, the good folks at Rutgers University have a dataset showing the weekly area of the extent of the snow in the northern hemisphere that goes back forty years or so. Here’s that data:
Figure 2. Rutgers University snow extent data. Note the missing data prior to 1972. Data Source: Rutgers Snow Extent Data
So … how is the extent of the snow trending over time? Well, if we look at the complete data, which extends from 1972 to present, here’s how that breaks down:
Figure 3. Decomposition of Rutgers snow extent data. Top row is observations. Second row shows the trend in the 52-week mean. Third row is the regular seasonal variations. Bottom row is the residual variation once the seasonal and overall trends are removed. Note the different scales on all four rows.
The second row in Figure 3, entitled “trend”, shows the changes in the mean value over time. The snow area generally dropped during the first half of the record. Subsequently, it first rose and then remained level in the second half. So the good news is that we don’t appear to be started into an ice age. The other good news is that we also don’t seem to be headed for a time when our children won’t recognize snow … overall, like most climate records, not a whole lot going on. However, that is unlikely to last forever.
Finally, some speculation. I have long held that the main two ways that we affect local climate are through land use, and also via airborne soot (or “black carbon”) and “brown carbon”. Brown carbon is the airborne carbon from inefficient combustion of wood, coal and other fuels. In addition to coming from forest fires, brown carbon mainly comes from billions of cheap stoves and open cooking and heating fires in the developing world. Because of the prevailing winds, a goodly amount of the soot and brown carbon produced in the northern hemisphere falls on the northern snow and ice. And because the carbon compounds are dark in color, they are warmed by the sun. This leads to a more rapid melting of the snow. It has been suggested that this is the reason for the retreat of the European glaciers since the 1800s.
Now, humans have been dumping large quantities of soot into the atmosphere for quite some time now, ever since we managed to tame fire. And presumably, for all that time that soot has helped to melt the northern hemisphere snows and glaciers, so they didn’t start lingering further and further into summer. So … would it not be truly ironic if pollution, in the form of soot and brown carbon, were all that has been holding off another ice age? And wouldn’t it be a cosmic joke if our efforts to clean up soot and brown carbon pollution were the straw that broke the back of the Holocene, and ushered in the new ice age?
Do I think that’s the case, that soot is all that is keeping the next ice age at bay? Y’know … I truly don’t have a clue whether that’s true or not. That’s one beauty of climate science, that there are so many mysteries.
I’m just saying, I’m keeping an eye on the snow extent …
w.
DATA AND CODE:
I’ve posted up a .csv file containing the Rutgers data here, and the R code to read it is here.
Snow insulates the ground, lack of snow does the reverse (at least in Chicago).
A blanket of snow (6-12″) will keep the ground warm enough to dig with a shovel, a lack of snow lets the ground freeze and requires a pick to dig even 3″ deep (I know from years of experience).
Was all the moisture/storm tracks pushed south of the area leaving clear skies to let whatever heat remained radiate thru clear skies ?
Whatever it was, it all came together in 1996, scared the hell out of my boss/mentor.
He was a civil engineer who worried that the sewers he design/built might freeze.
http://articles.chicagotribune.com/1996-02-02/news/9602020132_1_frost-pipes-near-record-low-temperatures
I wonder if that much frost slows down the spring?
Mmmhhh. Peak Oil. Now M. Hubbert was a smart dude, and based on what he saw in the ’50s, we were running out of gas (pun intended). He never envisioned directional drilling, fracking, and sucking oil out of rocks the well logs might have suggested were “wet” but all other indications said were unproductive. And, that doesn’t even begin to account for the fact that most fields, under primary production, never gave more than about 50% of potential yield, and many far less than that. A worthwhile exploration program might be to go back to old fields, and drill them differently, and frack them, and get more. Once I attend a talk at COFRC (Chevron Oil Field Research Center) in which an engineer proposed “mining” old giant fields: get under them, drill really big holes up into the producing zones, and “milk them” so to speak. Half or more of the oil ever discovered that was economic in the time of discovery has not been produced. That’s trillions of barrels, and there is all the new stuff yet to exploit, or even, identify. Peak Oil is way down the road.
There is no snow here in Brisbane. This proves Global Warming is real. We’re doomed.
Hmmmmm. Albedo. Light scatter. I wish I had eyes that could see into the IR. I have worked on a lot of light scatter meters in my time. None of them however have attempted to measure scatter in the IR. But I do know that light scatter for ice (ie. snow) and water based clouds must be vastly different because the packing density/interparticle distance of each is quite different. More importantly both ice and water droplets interact with the incident IR light differently because they have different extinction coefficients, so warm differently. And then there is the grazing angle. . . . you can readily see rainbows in water droplet clouds (n=1.31), while ice crystal clouds (n=1.33) although they produce the effect, happen at different angles.
In any case albedo change is one of those “rapid onset” emergent phenomena. Both snow and white puffy clouds appearing, must dramatically change the radiation balancing equations when they are present vs when they are absent, and don’t easily drift back to the prior state without a “snap” energy change, because both, when they appear, happen when latent energy changes occur!
Good thoughts as usual, Willis. Your writing never fails to make me think.
Willis Eschenbach says:
“To the diminishing clouds I’d add the loss of plant cover in the fall.”
What regions in particular?
Willis
With your passion for data, may I suggest that you actually LOOK at the oil production data by State and Country and analyze it.
Global conventional crude oil production effectively stopped growing in 2005, after having grown about 1 million bbl/day every year for 20 years. (Small increases since then are primarily non-crude oil).
See Economist James Hamilton documents how oil production in every US State has been following a Hubbert type curve, with almost States (regions) having already past peak conventional crude oil production.
Refusing to look at the data will not make it go away. By Adam Smith’s law of supply and demand, the ~10X increase in the price of oil over the last decade is not due to an abundance of liquid transport fuel!
“Oil Prices, Exhaustible Resources, and Economic Growth,” in Handbook of Energy and Climate Change, pp. 29-57, edited by Roger Fouquet. Cheltenham, United Kingdom: Edward Elgar Publishing, 2013. Working paper version here.
“Historical Oil Shocks,” in Routledge Handbook of Major Events in Economic History, pp. 239-265, edited by Randall E. Parker and Robert Whaples, New York: Routledge Taylor and Francis Group, 2013. Working paper version here.
40 of 54 countries have already peaked conventional crude oil production. Mazama Science shows export data of individual countries.
The International Energy Agency 2012 projects unconventional oil production in the US will peak around 2020 and not exceed the US peak of conventional oil in 1970.
With current oil depletion rates and low economic growth, the cost of developing replacement fuels over the next 40 years at current prices will be about $100 trillion dollars. $100,000,000,000,000!
No small change. Climate change pales by comparison.
Willis Eschenbach says:
“To the diminishing clouds I’d add the loss of plant cover in the fall.”
But surely that will give more albedo not less?
Variable response vs.. positive feedback, thanks to John A. Strictly technically, there is no feedback here, a feedback being defined by Wikipedia as requiring a loop. Here we consider the albedo and temperature as two independent variables.
Nitpicking aside, there is a theory of LINEAR feedback systems. John A. is correct that both snow deposition/thawing or cloud creation/dissipation (or a displacement by winds) has a highly nonlinear effect on temperature. A linear approximation probably won’t work in these cases.
I think you will find that ice ages progress slowly, that is, glacially slowly. So looking for ‘when the next ice age is coming’ is like watching the tide come in, it’s pretty gradual and boring.
Note that the world has been cooling for the last 10,000 years or so, which may be the general rate that will eventually lead to a greater and greater amount of ice. The LIA was probably the coldest in the last 10,000 years.
Also, some scientists have proposed the ‘long warmth of the Holocene’ as compared to previous interglacials as being due to human factors, namely agriculture (which has caused an increase in c02 levels, according to some, since the beginning of agriculture) and land clearing. An interesting idea, but I don’t actually buy it, as the amount of land clearance has not been that great, and I don’t think agriculture hasn’t greatly impacted c02 levels of that c02 has had much effect anyway. I also think that the purported ‘long warmth of the Holocene’ may be in part a function of better data in the last interglacial compared to previous ones, giving a recent warm bias. (The same problem that crops up with the lack of data in the MWP).
thingadonta says:
“I think you will find that ice ages progress slowly, that is, glacially slowly. So looking for ‘when the next ice age is coming’ is like watching the tide come in, it’s pretty gradual and boring. ”
“The Younger Dryas was an abrupt cooling event that took place between 12,800 and 11,500 years ago in the midst of the warming that followed the Last Glacial Maximum. Recent work suggests that the onset of the event occurred incredibly rapidly, possibly in a decade or less, and the termination of the event was equally sharp.”
https://www.e-education.psu.edu/earth103/node/640
Willis said:
“Runaway feedback only occurs when the feedback factor is greater than one.”
Larger or smaller than – 1 surely ?
Unless the initial forcing is cancelled completely there will be a permanent imbalance at ToA and loss of atmosphere eventually.
Less than – 1 and the initial forcing will accumulate a surplus indefinitely.
More than – 1 and the initial forcing will accumulate a deficit indefinitely.
Remember that, come what may, energy in and out at ToA has to be stable in the very long term.
There is no room for anything other than a – 1 feedback if there is any kind of thermostat.
There is room for cycling around the mean due to the fluid nature of air and water but that is all.
Willis Eschenbach says:
October 18, 2013 at 11:33 am
By all astronomical Milankovitch calculations, we should be falling back into an ice age somewhere around now.
Ehh. Where you got this?
Eccentricity: going down and will not go up beyond present level over 100 thousand years, obliquity: dtto – going down and will not go up beyond present levels ~100 thousand years, precession index low and will not go up 50 thousand years, 65N insolation: drift up expected due to precession cycle, will not go down ~20 thousand years, insolation of ocean due to precession cycle: almost highest possible (highest in MWP)…
So I really wonder what all Milankowitch calculations showing something to the meaning “we should be falling back into an ice age somewhere around now” you mean.
“By all astronomical Milankovitch calculations, we should be falling back into an ice age somewhere around now.”
It looks like inslolation rises again in 3000-5000 years:
http://www.leif.org/research/Solar-Insulation-Cycles.png
Willis: ” As an example, consider a feedback factor of + 0.5.”
Yes well. There’s ‘feedback,’ ‘feedback,’ ‘feedback factor,’ and ‘feedback factor.’ With all duplications intentional. In the happy instaland of calculus the feedback factor of an amp is input/output; with loop gain being the reciprocal. In uses from people that hate children and hydrocarbons, ‘feedback’ is any non-zero difference between a proposed input perturbation and any know output pertrubation. Without any regard as to whether there exists an amp at all. Where an amp is just a governor sitting in the feedback path.
A feedback factor as you described it is not a feedback factor. It is a step wise explanation of how the governor hits on bistability or hysteresis. It’s isn’t a bad explanation, but it’s the sort of thing John A was on about. That any positive feedback, as in the per-step feed, without a governor goes to infinity and beyond. It’s a Toy Story.
Which is also not what John A expressly stated. So he may be guilty of his own foul as well. I mention it as the only solution for his complaint, under the assumption that he knows what he’s on about.
And just for the note: Amps are always ‘powered’ in the electronic world. But it is only necessary that they perform a conversion process at some point. That items in cannot be treated fungibly with items out. With CO2 we may treat IR photons fungibly since one in is one out, and we could hardly care nor tell the difference between them. But the surface absorbs IR, converts it in a lewd atomic bump n’ grind, then emits a broad spectrum. We cannot say that each IR in is an IR out. They simply aren’t fungible.
With respect to the climate, as climate, the feedback fractor is Watts_in/Watts_out. Which need not be unity in any given time step, but must average out to unity across all time steps. The AGW apocalypta is predicated on the idea that the feedback factor is given by Watts_in/Temperature_out. But that’s not an amp. It’s a token, at best, of talking about the state of the governor in the amp.
Ulric Lyons says:
October 18, 2013 at 4:48 pm
Agreed, Ulric … but since the temperature is falling, once again it’s a negative correlation (blue/green).
w.
Willis Eschenbach says:
“I’d also include frost. Lots of places which don’t get snow often get frost.”
That often melts soon after sunrise, more so if there is less cloud cover of course.
Willis Eschenbach says:
“..but since the temperature is falling, once again it’s a negative correlation (blue/green).”
Here is what you said in the article:
“In the blue and green areas, on the other hand, the albedo goes down as temperatures rise.”
“Do I think that’s the case, that soot is all that is keeping the next ice age at bay? Y’know … I truly don’t have a clue whether that’s true or not. That’s one beauty of climate science, that there are so many mysteries.”
= = = = = = = = =
Spot on Willis (± 95%), many are those who have been blaming the soot for the melting of the earth’s permanent snow and ice. And it could be true. And good on you for making some speculations about it on paper.
One other thing which I have been looking at, when it comes to pondering “the end of this present Inter-glacial period” we enjoy just now is; what was the long (tall) stone structures called “Cleopatra’s Needle” used for in ancient times if it was not for measuring (or keeping “a check on” the Earth’s axial tilt? What if Milutin Milankovitch’s theory is slightly wrong when it comes to the ‘Tilt (and Wobble) of the Earth’s Axis’?
The theory says that the Earth’s axis fluctuates between 22 and 24.5 degrees every 41000 years. – The present tilt is around 23.5 degrees. The “Wobble means that if you put a cine-camera looking straight up on the North Pole it would film a complete circle of the stars above in 23.000 years (Oh boy, that,s some camera that is)
The theory also says that the Earth’s orbit pulsates, becoming more and less elliptical every 100.000 years and every 433.000 years.
If you look up Ice-core graphs (even the one Al Gore used in his Inconvenient Truth slap-stick film) you’ll see that there was indeed a very long interglacial period, a bit colder than the present one maybe – but just as long (durable) or maybe even longer still.
So, Milankovitch who had never seen an Ice Core-graph is on pretty solid ground, but even so – “Why do the Sunlight shine through a certain “hole” in the walls of, say Stonehenge in UK and it hits a certain spot on an other wall on a certain time of a certain day of every year, just as it must have done 7.000 years ago when it was first built, if the Earth is continually changing its axial tilt and wobble?
Anyway, what happens at the Equinoxes on September and March the 21? – Well, that’s when Spring and/or Autumn happens in both/either Hemisphere/s, because the “Axial Tilt” (AT) is neutral, just as it would be all the year round if the ‘AT’ was 0 or just a few degrees.
So, what if the “Cleopatra’s Needles” were products from a time just after the “Younger Dryas (YD) frost period, – and the YD came about because the Earth is not as stable on its axis as we assume? Maybe it can vary much more wildly than we think. Maybe the Axis is quite upright for 100.000 years or so, keeping the “Summertime” away from both Hemispheres “permanently”, then what?
I truly don’t have a clue whether the above is true or not, but it could be. – And it could also be “laughed out of Court”. Hope none of us – living today – will find out for sure.
Hi Willis and thank you for your work.
Assume first that I am concerned about the advent of major global cooling within the next thousands of years.
My question is this:
IF we were faced with an impending global Ice Age, could we defer it indefinitely by deliberately spreading soot over very large areas of snow?
Are there any better means of deferring an Ice Age?
Best personal regards, Allan
[Please do not say add more CO2 to the atmosphere – I’m pretty sure that will not work – ECS is too low, if it exists at all. :-} ]
Phase 3 initiated.
Just a minor nit, and not unique to Willis’s writing, and doesn’t detract at all from what he wrote here.
Unless I’m mistaken, the earth has been in an “ice age” for several hundred thousand years. During that time, we have gone through several periods of “glaciation”, interspersed with relatively shorter “interglacial” periods. So it’s not pedantically 😉 correct to say that we came out of an “ice age” about 10,000 years ago, and will go back into another “ice age” sometime in the future. I don’t think anyone really knows if the current “ice age” has ended yet, or if it ever will end. Assuming the current “ice age” hasn’t ended yet, we are very likely heading toward another period of “glaciation”.
Ulrich Lyons: Yes but the Younger dryas was likely not related to the causes of major ice ages, its more likely a blip.
Hey Poptech. Anthony has been more than tolerant regarding your recent meltdown. You’re looking like you want to graduate from troll to stalker. Do yourself favor and go chill..
The initiator of the next ice age is when the snow does not melt in the summer on Ellesmere Island and the sea ice does not melt out at 75N.
The projections are this will continue for as much as 125,000 years (not 50,000 but 125,000 years).
At Eureka Nunuvut Canada at 79.5 degrees north (which has a world-class weather research station staffed by several scientists), the snow left on June 18th and didn’t permanently return until August 14th. And this was a relatively cold summer at Eureka, probably the coldest in 20 years.
That still leaves 57 days of no snow or nearly 2 months in a relatively cold year. Much cooling is required to drop that to Zero days and kick off the next ice age. Get used to the interglacial because it will be the longest one in the last 2.7 million years.
http://climate.weather.gc.ca/climateData/dailydata_e.html?StationID=1750&timeframe=2&Year=2013&Month=6&cmdB1=Go
http://climate.weather.gc.ca/climateData/dailydata_e.html?StationID=1750&timeframe=2&Year=2013&Month=8&cmdB1=Go
http://www.cpc.ncep.noaa.gov/products/global_monitoring/temperature/tn71917_1yr.gif
“I’m keeping an eye on the snow extent ”
The “canary in the coal mine” is the Athabasca glacier in Canada. When it advances, watch out. It is thought by some that this is where the western ice sheets of North America originated and then spread down across Alberta. The snow field from which the Athabasca originates feeds several glaciers and feeds into the Arctic, Pacific and Atlantic oceans. Glaciers from this snow field can stretch to Washington State and/or to Montana.
Watch the Athabasca glacier. As long as it is stable or in retreat, we’re doing just fine.