Too many variables like clouds to model future climate with precision
Guest essay by Rolf Westgard
A new United Nations report suggests an imminent danger from global warming. It states that without drastic action we may have “to develop the ability to suck greenhouse gases out of the atmosphere and store them underground”.
Minnesota already has millions of devices which do that. They are called trees and plants. They take in carbon dioxide(CO2), store the carbon(C), and return the oxygen(O) for us to breath.
It is actually not clear that our fossil fuel burning CO2 emissions are a serious global warming threat. There are many poorly understood ocean temperature variables which have a bigger impact on earth temperatures. These include the El Nino cycle and the Pacific Decade Oscillation. Confusion over how those work helps to cause the UN’s Intergovernmental Panel on Climate Change(IPCC) to regularly over estimate temperature warming trends.
Undeterred, federal and state legislatures are spending billions in response to guesses about our climate future. In addition to ocean cycles, there are several other poorly understood natural climate feedbacks. These act as natural thermostats, keeping the earth’s average temperature during inter glacial periods within a fairly narrow range. One of the most important is the action of clouds. Clouds are water vapor, a green house gas which warms us. Clouds reflect the sun’s light, cooling us. Clouds produce rain which removes CO2 from the atmosphere, etc.
A few lines from a popular song about clouds, “Both Sides Now”, pretty much sums up where we are with clouds and other climate variables:
“But now they only block the sun, they rain and snow on everyone.
So many things I would have done but clouds got in my way.
I’ve looked at clouds from both sides now, from up and down, and still somehow
It’s cloud illusions I recall.
I really don’t know clouds at all.”
At this point, no one knows how to accurately plug the impact of clouds or other climate variables into climate forecasting models.
(Westgard is guest faculty on energy subjects for the U of MN Lifelong Learning
program. He recently taught class #17016 “America’s Climate and Energy Future: the Next 25 Years”)
“”””””……….QUOTATION…..Matt G says:
February 11, 2014 at 1:08 pm
george e. smith says:
February 11, 2014 at 10:03 am
“Low clouds tend to warm the atmosphere because of their back radiation of IR (Heat) frequencies…..””””””
Lower clouds are usually of the heavy moisture laden kind, that precipitate, and they block a whole lot of solar radiation from the surface; which results in cooling.”…..END QUOTATION.
Matt please don’t post statements made by others and allege that I said them.
I take great pains to delineate items that are direct excerptions from other people’s posts.
Now here is where you got that:
QUOTATION……””””””……george e. smith says:
February 11, 2014 at 10:03 am
per darylb,
“””””…..In general high clouds and vapor in the atmosphere tend to cool the earth and Roy Spencer has indicated that only a 1 or 2% change in the higher atmosphere could account for all the changes we see. The higher clouds cool because on average they reflect more solar irradiance back into space. Incidently, Spencer used that ‘I have looked at clouds from both sides now’ in his book.
Low clouds tend to warm the atmosphere because of their back radiation of IR (Heat) frequencies…..””””””
Actually, the usual weatherman wisdom, is exactly the reverse. The standard weather text books claim that high clouds warm, and the higher the warmer., while low clouds cool…….”””””””……END OF QUOTATION.
Now note Matt that I was directly quoting a post by ……darylb……. NOT ME.
Did you not then see this part…….QUOTATION……””””””……Actually, the usual weatherman wisdom, is exactly the reverse. The standard weather text books claim that high clouds warm, and the higher the warmer., while low clouds cool…….”””””””……END OF QUOTATION.
I quoted ……. darylb, ……. and then pointed out that this (his statement) was contrary to the common belief.
Now if ….darylb…. did not say that himself, but was quoting some other source, he made no indication of that.
Well Matt, we crossed posts in the atmosphere; no harm ; no foul, play on.
George
Stephen, you still must admit the null hypothesis, that it is all intrinsic oscillations interacting to produce both long and short term weather pattern variations. You must. And I think you know why. Scientifically, your idea is speculation. There is plenty of evidence that Earth’s own variability has been the source of interglacial and glacial weather pattern variations (climate shifts). So it must hold for the present, at least, as being the null hypothesis that all must not only show is insufficient (and none have as yet), but that alternate theories explain more than the null hypothesis does.
Therefore to be taken seriously, you must state the null hypothesis also, being that your hypothesis has not been verified even the least little bit, which you have admitted to stating you will leave to others the job of calculations and specific physics (chemical as will as physical properties) based plausible and observable teleconnections related to your combo meal of top down and bottom up mechanism.
That would be an improvement on your comments here. As it is, you state your thoughts as if they are fact. Your ideas are clearly not fact. You demonstrate hubris, which detracts from your desire to be considered a scientist.
Pamela.
The null hypothesis is that all climate change is natural.
You are trying to exclude the possibility of a top down solar effect from that natural variability.
There is plenty of data and many recent papers suggesting a solar / climate link.
I have pinned my hypothesis very firmly to an easily falsifiable ozone / solar interaction affecting tropopause height differentially between equator and poles.
It is established physics that such differential effects on tropopause height can be caused by temperature variations above the tropopause and that tropopause height can affect the pressure distribution beneath the tropopause.
The sequence of events set out in my New Climate Model matches observations and basic physical principles unless you can produce evidence to the contrary.
If my tone offends your sensibilities then that is your problem.
In the time that I have paid any attention to the weather; the last few decades, and more recently since the age of WUWT, somewhere between a dozen, and a hundred; or more people have posted that high cirrus clouds cause positive feedback warming… The argument is that their small “optical depth” still lets a lot of solar energy through to the ground, compared with low thick clouds, and then they absorb all this upward LWIR and often evaporate letting more solar energy to the ground, and assorted variations on that theme.
So I should state here, Smith’s firs axiom, of Cloudology.
“In the study of the effect of clouds, on weather/climate/skiing/whatever, the default state or condition is…NO CLOUDS… !!
Now Al Gore is the only person who has ever seen the earth from outer space, in its default NO CLOUDS state. He took a picture and published it in “An Inconvenient Truth.” Not a cloud anywhere.
I have seen the earth with NO CLOUDS, many times, but only from the ground side; well it was cloudless from horizon to horizon in all directions, even from a somewhat high (called mountainous) position.
So what is a cloud ?
Well I’ve been as high as 40,000 ft in a plane, and never seen clouds above that, but they might exist. I’ve heard of 45,000 ft tops of thunderheads. Dunno if that’s true.
But I’ll be generous and say clouds exist below 20 km. Yes I know there may be higher ones but not in any amount likely to change the climate, so that’s 20km or 60,000 ft.
The angular diameter of the sun is about 30 arc minutes; let’s call that 1/120 radians. So a 20km cloud needs to be 167 meters or 500 ft in diameter to occult the sun.
Anything smaller than that is an aerosol, but lower clouds can be smaller.
If you are standing in CAVU conditions, in bright sun, and a 500 ft cloud goes in front of the sun at 20 km height, you will be at the center of a 1500 ft diameter penumbral disc, and will see just the bright edge of the sun peering around the cloud. And it WILL register lower solar energy at your location, and it will get colder. I have never experienced it to warm up when a cloud goes in front of the sun; yet all the while that cloud was sitting there returning surface origin LWIR radiation back to me to keep me warm. No it got colder (instantaneously).
Larger clouds, than the minimum, will cast a bigger shadow, that takes longer to pass by, and all that time, the surface is cooling frantically from LWIR emissions, and as it cools, the LWIR returned from the cloud is also diminishing.
I have measured hot blacktop pavement in the late summer afternoon, and by the end of evening twilight, it is quite cool to the touch.
Now notice that my definition of a cloud, as being at least 30 arc minutes diameter favors high clouds for LWIR warming, because they are larger than low clouds, and it is claimed still stop all the LWIR, at least in the water bands. Note also that the higher the cloud, the less LWIR from the surface reaches it because of more CO2 and water vapor between ground and cloud, so this reduces the cloud irradiance from surface LWIR, which in turn reduces the re-emitted LWIR from the cloud’s water/CO2 bands, and the lower Temperature thermal spectrum emission too. That lower down LWIR now has to make it through that thicker layer of GHGs, to get back to the surface.
Richard Courtney, says the bottom 100 meters of atmosphere absorbs all the CO2 band emissions. OK, so at higher altitudes, that 100 meters will have expanded to maybe 1,000 meters to absorb all the CO2 band (coming down). OK, it is still 19 km back to the surface.
You see this claim that high clouds warm, simply doesn’t hold water. Sure they slow down LWIR escape, but the Temperature measurements (in a cloud shadow) show that they block more solar energy than they do LWIR.
I’ve been in mid west Sunday afternoon (4PM) flash thunderstorms, and even inside the house looking out at the fireworks, when the storm cloud passes over the sun, the heating stops even inside my house, standing at the window. So the effect is radiant energy, and not atmospheric Temperature cooling which is a slower effect.
Then as I said, it is CHANGE (cloud anomalies) that persist for climate time scales that we should keep in mind.
Make that a 1,000 foot penumbral disc, with a 500 ft cloud Umbrage in the center.
george e. smith says:
February 12, 2014 at 11:27 am
Sorry, I got mixed up with the quotations and your response was far more accurate.