From ARS Technica
We aren’t likely to see it happen, but it’s still sobering.
Scott K. Johnson – 2/25/2019, 6:13 PM
Stratocumulus clouds, like those in the lower two-thirds of this image, are common over the oceans.
The word “hysteresis” doesn’t immediately seem threatening; it hints at a portmanteau of “history” and “thesis”—a dense read, perhaps, but those never killed anyone. But that’s not what the word means. Hysteresis is a profound behavior some systems can display, crossing a sort of point-of-no-return. Dial things up just one notch, and you can push the system through a radical change. To get back to normal, you might have to dial it down five or six notches.
Earth’s climate system can provide examples. Take the conveyor-belt-like circulation of water in the Atlantic Ocean. Looking back at the past, you can see times that the circulation seems to have flipped into an alternate pattern regarding climatic consequences around the North Atlantic. Switching from one pattern to the other takes a significant nudge, but reversing it is hard—like driving up to the top of a ridge and rolling down into the next valley.
A new study led by Caltech’s Tapio Schneider may have identified a disturbing hysteresis in Earth’s climate—a shift in cloud patterns in response to warming that could quickly heat the planet much further. If we were to continue emitting more and more greenhouse gas, we’d eventually end up running this experiment for real. (Let’s not, please.)
Cloud services
The center of this drama is a particular type of cloud. Stratocumulus clouds typically blanket about a fifth of the low-latitude ocean. Most clouds are formed because air warmed by the Earth’s surface (or forced over mountains) cools as it rises, condensing water vapor to cloud droplets.
Stratocumulus clouds are a little different. The convection that lifts their moisture isn’t driven by warming at the bottom but by cooling at the top.
The water in this cloud deck absorbs much of the infrared radiation emitted upward from the warm surface. The cloud deck re-emits some radiation back downward and some into outer space. The air above these clouds is drier and absorbs much less of the outgoing energy passing through it. That means you can think of these clouds like the cooling fins of a radiator. They shed more heat upward than they receive from the atmosphere above them, allowing them to cool off from the top down. The cold air at the top of the clouds sinks, setting up a convection loop that brings water vapor up from the sea surface to the cloud deck.
So, what happens to this unique process in a warmer world?
Nothing but blue skies
To tackle this, Schneider and his colleagues flipped things around. They utilized a model that can simulate these clouds in a small patch of atmosphere—given a simplified version of the world around them. Specifically, they simulated a patch of the subtropical ocean with stratocumulus clouds above and a neighboring patch of tropical ocean responding to global warming. They did this for varying concentrations of greenhouse gas equivalent to 400 parts per million of CO2 (similar to today) on up to 1,600 parts per million.
Up to about 1,000 parts per million, there were no major surprises. Things got around 4°C warmer and numbers changed for things like water vapor and cloud altitude. But the cloud deck generally looked familiar.
At about 1,200 parts per million, however, the simulated clouds suddenly dissipated. And without that shade reflecting sunlight, the world warmed another 8°C.
Processes responsible for the cloud deck breaking up around 1,200 ppm CO2 in the model. Temperatures shown in units of kelvins.
Schneider et al./Nature Geoscience
How is CO2 flipping the switch on these clouds? The researchers found a pair of simple processes working together in their simulation. First, warmer air carries more water vapor up from the sea surface, and when that water vapor condenses, it releases a lot of latent heat. That extra latent heat gives the air a little buoyancy boost, increasing the turbulent movement that can mix dry air from above into the cloud layer. This dries out the cloud deck and makes cloud formation less likely.
We all know that Venus is cloud free.
Tapio Schneider says: “Stratocumulus clouds are a little different. The convection that lifts their moisture isn’t driven by warming at the bottom but by cooling at the top.”
An extraordinary statement coming from someone with his qualifications. Does he not know that the clouds get where they are because water vapor is lighter than dry air ( see the respective molecular weights). It is this resulting buoyancy that drives the water up through the atmosphere NOT in any way due to temperature differentials creating convection.
Is he not aware that the Hydro Cycle behaves as a Rankine cycle? If not then he should go back and mug up on basic thermodynamics and the properties of water, before next pontificating nonsense on the media.
Having read this bit I’m afraid I switched off reading the rest with any interest.
Convective energy comes from two sources. The temperature difference between the rising parcel and its surrounding, as well as the density difference due to water vapor between the parcel and the ambient air. This is accounted for by using a virtual temperature which is the dry air temperature with a correction for moisture. The virtual temperature can make a big difference in the early stages of convective development when the convective energy is small. It has much less effect when the convective energy becomes large with well developed towering cumulus cloud.
That’s the first egregious mistake I saw too, Alasdair. I forged on, however, and found all the other unscientific crap.
As Tim Gorman pointed out earlier, what happens to all that water vapour from increased ocean evaporation in their warmer world? I submit that they haven’t gone far enough in their modelling because they don’t talk of ……………………. tropical thunderstorms! (which we’ve heard all about from Willis. Thank you Willis for all that.) Masses of towering cumulo-nimbus transporting heat high into the atmosphere and sending down cold rain every afternoon.
There’s no rain in their model!
Their sub-tropical surface temperature of 305°K = 32°C is going to make the sub-tropics just like the tropics are now, and their tropical surface temperature of 315°K = 42°C is almost certainly impossible because there would be so much evaporation when the surface temp started going over 30°C, there would be constant 100 percent cloud cover (projected temperatures are at the bottom of their cartoon).
It’s just not believable. Like so much of climate science.
Very first off, I had a skim through the equations in the model and it does appear they try to account for precipitation in some manner.
Your other point is good, what about thunderstorm formation when the stratocumulous dissipates. More heat will reach the surface resulting in more evaporation and more convection.
This process is evident in the summer over the land. Often, in the morning, there is a deck of stratocumulus formed by the overnight cooling of the air to the form the cloud. Then when the sun comes out the lower levels begin heating up and the stratocumulus gradually dissipates due to the heating and turbulent mixing in of drier air. Once the stratocumulus dissipates the convective clouds will form quite rapidly and eventually thunderstorms may result.
This can be a very tricky forecasting problem as to when/if the stratocumulus will dissipate and thunderstorms form up. I have been caught more than once by persistent stratocumulus that did not want to dissipate and the thunderstorm forecast did not occur.
I believe Willis postulated that many parts of the tropics reach their maximum ocean T now. At about 90 degrees F ? the evaporation increase is exponential and thundercloud formation happens rapidly.
Also this study is based on the highest IPCC ECS scenario. ( The world is disproving that scenario today) Additionally the day time tropical T has hardly changed at all, so is most certain to never reach their hypothetical.
” They really don’t know clouds at all.”
Back in the day, before computer models were the be-all, end-all of “science”, we had a saying about computer models: GIGO. At the very least the authors should publish the actual code of their model so the experiment can be replicated. Come to think of it, maybe the IPCC could do that, too…
Oh. I see EdH is way ahead of me. Thanks for the link to their code! I haven’t looked at it in detail, but since we’re dealing with clouds, is there room in there to model cosmic rays and sunspot activity? Or other parameters? For example, if the oceans warm up as “predicted” wouldn’t vertical circulation in the seas bring more organic material from depth to surface, vastly increasing the life forms in the ocean, which feed the sea birds, who will multiply in an exponential way, and whose white wings will reflect enough sunlight to increase the albedo of the planet and introduce cooling to moderate the deadly warming? Just a thought, but any government sponsored Ph.D. student is welcome to it…
I tell my friends that all of the time. Especially one of my former clients (who happened to be a Director of Environmental Quality for a prominent city government where I come from), who when she mentioned the models she had seen as the proof of what was happening to the climate. It’s all garbage in, garbage out.
Gospel out……….Garbarbage In Gospel Out.
This is an obvious example of gigo — model blows up when driven out of bounds of normal atmospheric physics indicating the model is wrong and the researcher needs to go back and debug.
No, Ltp. The researcher needs to become a barista.
Gordon
I agree, this is not an example of hysteresis. Typically the word is used to describe an efficiency loss to phenomena inherent in the properties if a system. Consider why AC transformers get warm. As the magnetic field reverses, the core tries to remain in its present state. It gets warm.
Pb = η * Bmax^n * f * V
Pb = hysteresis loss (Watts)
A tipping point is quite different. That would be like having a material that heats up, a certain flux density, then suddenly stops doing that, and cools as the rate of change in magnetization increased. Good luck finding that material.
What they describe is claimed to happen in the model above some CO2 concentration. That might be an emergent phenomenon, not a hysteresis.
“Stratocumulus clouds are a little different. The convection that lifts their moisture isn’t driven by warming at the bottom but by cooling at the top.”
Balderdash. Convection is driven by exactly two things; density difference caused by the average molecular weight of gases or density difference caused by temperature. It is also known as the buoyancy effect.
Show me a cloud that doesn’t cool at the top! A white cloud in IR is “black” and radiates with an emissivity of almost 1.0. High nines at least. Same for water vapour.
They argue for a different kind of thermosiphon based on the cloud height/type. By what mechanism can a vaporous cloud top suck up gases from below? The evanescent cloud top beckons with its little cloudy fingers?
Even the concept that water vapour condenses and dumps heat into the air raising the temperature …this is ridiculous. It condenses because it is cold or super-cooled and immediately, as it condenses, radiates the energy into space or back to the atmosphere and ground. Remember it is black in IR. If you only see IR radiation, all water would be black like crude oil.
The idea that heating the oceans in the tropics 4 C would cause clouds of this type to disappear shows the model is defective. Suppose it were true: other types of cloud would form and block the sun, and that would happen long before 4 degrees was reached. Willis has shown (and published the paper) that it is very difficult to get an ocean above 31 C at the surface because it shades itself with huge clouds above 30.
They propose that a rising temperature and evaporation rate would reduce cloud cover to zero. Good luck with that.
Consider the opposite. A hot Earth with hot oceans and no such clouds, in equilibrium. Cool the oceans, reducing the evaporation rate, and suddenly clouds appear? A cooling ocean with reduced evaporation creates the emergent phenomenon of cloud formation? Whereas before the evaporation rate was so high, clouds couldn’t form? And being so warm they couldn’t radiate into space? From the moment water leaves the ocean as vapour, it is radiating IR.
Good grief. How did this get past peer review? It is thermodynamic gibberish.
+10!
There’s no way to verify this model against actual data. If even one negative feedback in a complex model is ignored or underestimated the conclusion is erroneous.
If the waters are getting warmer, wouldn’t there be more hurricanes to transport that heat to the upper atmosphere?
I would like to see a list of their assumptions.
A significant problem with this study is that the models they used claimed a 4C temperature increase from only 1000 ppm. Clearly, the model is broken as 1000 ppm is less than 2 doublings, the first of which will cause at most a 1.1C increase and the second will cause even less. It’s likely that the same flaw is causing the clouds to disappear at 1200 ppm.
The disappearance of clouds at higher ocean temperatures is obviously wrong. If anything, what we see is that ocean temperatures clamp at a little over 300K (about 80F) as the latent heat of evaporation becomes enough to offset incident solar energy. With this much water vapor entering in the atmosphere, clouds are inevitable as water vapor rises and cools.
One problem with their mechanism is that the release of latent heat is into the cloud water being condensed upon and not the surrounding air molecules. Also, the only way to ‘dry out’ the cloud deck is for it to rain and that also requires clouds. If what they claim is true, why is the average cloud coverage across the inter-tropical convergence zone larger than the average cloud coverage elsewhere?
It sure looks like confirmation bias got in the way here …
Confirmation bias renders the whole thing junk science the moment they ASSUME that CO2 levels “drive” temperature, when there is NO empirical evidence in support of that.
The basic finding here is that CO2 above a certain level will cause a rise in temp sufficient to prevent clouds from forming. But they seem to be only talking about one sort of cloud-strato cumulus.
Besides for that head scratcher, they are ignoring several findings from long accepted values from the paleo record: That for most of the earth history, CO2 was far above the level they specify as critical. And for most of the Earth’s history, the Earth was stuck at about 10 C warmer than present. Far more than the 4 degrees they claim will cause the end of clouds.
But those periods of time/ with Earth at about 22C, the planet was very wet.
Geologists have long known that warmer periods of Earth’s history were far more “humid” as geology texts refer to these wet periods.
Carboniferous, when vast forests covered the Earth for tens of millions of years. Jurassic, Triassic, Cretaceous?
Wet. Wet Wet.
Wet wet wet.
And rainy.
The obvious conclusion is that these turkeys are just making this crap up.
Like everything else they would have everyone believe.
Maybe, maybe not.
We’re doomed, anyway.
https://www.nature.com/articles/s41561-019-0310-1.epdf?author_access_token=0KiqRkFsS6qEi37dkGz8X9RgN0jAjWel9jnR3ZoTv0Nq8LfnDsfOJgJee7VyE1P3etD8357qMjqyq2BVVSP5V9bFmsDkWYfYyGV7gtmSgJncc5u_hUNNfMaYS7BFcu8_tWNipaYj6kz2PMZ8OXu5CQ%3D%3D
The above is actual link to study but Nature Geoscience won’t let you print it. Ron Clutz nailed most of the criticisms above. I will add a couple of comments.
No. 1 What they did was run 2 different types of climate models a) a model that dealt with clouds only with simplified global physics and b) the regular complicated physics model with the usual global cloud parameterizations. They inputted the results of the cloud model into the general model. THIS HAS A MAJOR FLAW. By running the cloud model with a simplified version of the global physics, you end up with variables that affect the clouds that come from the general model but are dealt with at a vastly simplified scale. So even though your cloud resolution is good in the cloud model, its findings are not. Then when you input these findings into your general model, you cant be sure whether the error bars are lower or higher than if you just ran the general model without the findings from the cloud model. If this wasnt true, we could model a raindrop and then model a cluster of raindrops, and work our way up the ladder until the whole globe was modeled. It might involve having a 1000 different staged models. The problem is we wouldn’t know what the error factor was. I predict that if climate scientists attempted that, the 173 year predictions would be so ridiculous, that the climate scientists would go back to the way that it is done now ; just 1 big simulation run 100’s of times with different inputs.
No.2 Not only are the mechanisms uncertain but they don’t take into account; super saturation because it can’t be measured at the present time. They assume a climate sensitivity number . Also they varied a parameter called Instability. This parameter was based on an equation that needed variables like latent heat flux at the surface which can’t be measured. Also turbulent entrainment of dry and warm air cannot be measured. Also they played around with temperature inversion (subsidence) and varied it by 1 to 3% / Kelvin .
That means the models have no way of calculating when or by how much temperature inversions happen. They freely admit that subsidence weakens under warming and counteracts the whole process.
No. 3 This follows from no. 4.
No.4 is certainly apropos. if you solve the Keeling CO2 curve for 1200 ppm you get 173 years from now.
The Keeling net CO2 in atmosphere curve is approximated mathematically by the formula:
ppm = 0.013 t^2 + 0.518 t + 310.44 where t = the time in years since 1950
setting the equation = 1200 and using the quadratic formula of (-b +/- ( (b^2 -4ac)^ 1/2)) / 2a
gives t= 242. Adding that to 1950 gives the year 2192. That is 173 years from now. Solving it for 5000 ppm (UK and US workplace safety limit) gives 511 years from now where we potentially choke to death, assuming we find and burn enough FF to emit that much CO2. The alarmists will not let this go after their warming theory completely falls apart. This does bother me because the thought of mankind choking on his/her prosperity is a worry even if it is 511 years away. However some skeptics say that we will never be able to burn that much fossil fuels because we will run out way before then. I am not so sure.
However I still have a feeling in my gut that the CO2 numbers will either level off or they are fraudulent in the 1st place. Why arent more organizations/ agencies measuring the CO2 in the atmosphere?
No. 5 Tony Heller has pointed out that the only way to have no clouds is to have no oceans.
Does this mean we are all going to die?
The article contains the common fallacy of CO2 as the one and only “control knob”: “For example, the Arctic was frost-free during the early Eocene, around 50 million years ago. However, current GCMs only reproduce a frost-free Arctic at CO2 levels above 4,000 ppm”
But (citing https://ucmp.berkeley.edu/tertiary/eoc/eoctect.html):
«In the middle Eocene, the separation of Antarctica and Australia created a deep water passage between those two continents, creating the circum-Antarctic Current. This changed oceanic circulation patterns and global heat transport, resulting in a global cooling event observed at the end of the Eocene.»
“Hysteresis is a profound behavior some systems can display, crossing a sort of point-of-no-return.”
That isn’t what hysteresis is at all. From Wikipedia, “Hysteresis is the dependence of the state of a system on its history.” Hysteresis means the return path isn’t the same as the outgoing path, creating this characteristic magnetic field strength diagram, which shows the fundamental principle used by magnetic storage media of all types.
Not scary at all.
Take the conveyor-belt-like circulation of water in the Atlantic Ocean. Looking back at the past, you can see times that the circulation seems to have flipped
There you . Opening statement and we are already in speculation mode
Tipping point in the clouds, what more rubbish can they come up with?
The droughts that are coming soon now are going to be a problem,
starting round and about this year. It happens every 87 years or so.
Europe had a dry summer 2018 already. USA will be next.
Click on my name to read my report on that.
Well, according to the IPCC reports, clouds are, you know, “poorly understood.” So they must be a great place to twaddle about in their latest attempt to keep THE CAUSE going when searching for “tipping points” and “missing heat” and all those other mysteries they have no REAL evidence to support their endless assertions of the existence of.
California will get a lot of water in the spring.
Clouds aren’t based on physics. They’re parameterised entities and their formation is based on rules such as the humidity level, temperature and pressure.
So when they’re taken way, *way* out of their expected ranges all bets are off as to how they behave.
This paper is some scientists having some lulz. The problem is people actually take this stuff seriously.
“That extra latent heat gives the air a little buoyancy boost, increasing the turbulent movement that can mix dry air from above into the cloud layer. This dries out the cloud deck and makes cloud formation less likely.”
So where does all that evaporated water go then? Does it just disappear into nothing? This seems to be just another proof that climate models can’t handle convection realistically. Which is not news.
Ron Clutz wrote about this paper here: https://rclutz.wordpress.com/2019/02/26/clouding-the-climate-issue/
I think you are all wrong!
Look at this quote from one of their reference papers: ” The simulations validate this framework for studies of MBL clouds and establish its usefulness for studies of how the clouds respond to climate change”!
Its been proven by simulation!
Do I need a /sarc ?
“Hysteresis” Sounds like a good description of global warming followers.
Couldn’t find the word “rain” above the comments.
Stratocu normally forms, in my observation, from wind turbulence. That’s why it tends to lurk at around two to three thousand feet– ideal to hide under if you’re a maritime strike aircraft. The rising air currents take the CCNs up to the condensation level.
If they want to play with computer models, might I suggest that the team studies what happens if for some reason there are fewer CCNs. Possible scenarios: reduced plankton-produced DMS; oil-smoothed surface producing fewer breaking waves and thus less spray.
It’s the condensation particles. Fewer CCNs, less cloud cover, more warming. Google ‘ship tracks nasa’.
Sheesh.
JF