Climatologist Dr. Roy Spencer has pointed out in his book,
“The most obvious way for warming to be caused naturally is for small, natural fluctuations in the circulation patterns of the atmosphere and ocean to result in a 1% or 2% decrease in global cloud cover. Clouds are the Earth’s sunshade, and if cloud cover changes for any reason, you have global warming — or global cooling.”
We continue that conversation with this entry from Paul Homewood.
We’ve been discussing the sudden rise in UK and European temperatures in the 1990s, and I was reminded about a study undertaken by Clive Best and Euan Mearns looking at the role of cloud cover four years ago:
Clouds have a net average cooling effect on the earth’s climate. Climate models assume that changes in cloud cover are a feedback response to CO2 warming. Is this assumption valid? Following a study with Euan Mearns showing a strong correlation in UK temperatures with clouds, we looked at the global effects of clouds by developing a combined cloud and CO2 forcing model to sudy how variations in both cloud cover [8] and CO2 [14] data affect global temperature anomalies between 1983 and 2008. The model as described below gives a good fit to HADCRUT4 data with a Transient Climate Response (TCR )= 1.6±0.3°C. The 17-year hiatus in warming can then be explained as resulting from a stabilization in global cloud cover since 1998. An excel spreadsheet implementing the model as described below can be downloaded from http://clivebest.com/GCC
The full post containing all of the detailed statistical analysis is here.
But this is the key graph:
Figure 1a showing the ISCCP global averaged monthly cloud cover from July 1983 to Dec 2008 over-laid in blue with Hadcrut4 monthly anomaly data. The fall in cloud cover coincides with a rapid rise in temperatures from 1983-1999. Thereafter the temperature and cloud trends have both flattened. The CO2 forcing from 1998 to 2008 increases by a further ~0.3 W/m2 which is evidence that changes in clouds are not a direct feedback to CO2 forcing.
In conclusion, natural cyclic change in global cloud cover has a greater impact on global average temperatures than CO2. There is little evidence of a direct feedback relationship between clouds and CO2. Based on satellite measurements of cloud cover (ISCCP), net cloud forcing (CERES) and CO2 levels (KEELING) we developed a model for predicting global temperatures. This results in a best-fit value for TCR = 1.4 ± 0.3°C. Summer cloud forcing has a larger effect in the northern hemisphere resulting in a lower TCR = 1.0 ± 0.3°C. Natural phenomena must influence clouds although the details remain unclear, although the CLOUD experiment has given hints that increased fluxes of cosmic rays may increase cloud seeding [19]. In conclusion, the gradual reduction in net cloud cover explains over 50% of global warming observed during the 80s and 90s, and the hiatus in warming since 1998 coincides with a stabilization of cloud forcing.
Why there was a decrease in cloud cover is another question of course.
In addition to Paul Homewood’ piece, we have this WUWT story from 2012:
Spencer’s posited 1-2% cloud cover variation found
A paper published last week finds that cloud cover over China significantly decreased during the period 1954-2005. This finding is in direct contradiction to the theory of man-made global warming which presumes that warming allegedly from CO2 ‘should’ cause an increase in water vapor and cloudiness. The authors also find the decrease in cloud cover was not related to man-made aerosols, and thus was likely a natural phenomenon, potentially a result of increased solar activity via the Svensmark theory or other mechanisms.
Discover more from Watts Up With That?
Subscribe to get the latest posts sent to your email.
I’m having difficulty finding the ISCCP global averaged monthly cloud cover data (my computer can’t open any of the data from the links), but the claim that ‘temperature has flattened’ since 1999 is just nonsense, even using the coolest of the surface data sets, HadCRUT4, as this author does.
http://www.woodfortrees.org/graph/hadcrut4gl/from:1983/to:2009/plot/hadcrut4gl/from:2009/plot/hadcrut4gl/from:2009/trend
Above is HadCRUT4 from 1983 (per the chart) with the period since 1999 shown in green. Sorry, but that is not a ‘flattening’, it’s statistically significant warming at a rate of 0.163 ±0.098 °C/decade (2σ); so if cloud cover has ‘flattened’ since 1999, then that more or less puts paid to this theory (and perhaps explains why the data in the chart stops in June 2008, more than 10 years ago!).
Sorry, wrong chart (that one is from 2008, when the chart data stops, which is even faster, at 0.3 C dec). Here is HadCRUT4 from 1983 with the so-called ‘flat’ period since 1999 in green: http://www.woodfortrees.org/graph/hadcrut4gl/from:1983/to:1999/plot/hadcrut4gl/from:1999/plot/hadcrut4gl/from:1999/trend
This was discussed in my 2014 paper “Late twentieth-century warming and Variations in Cloud Cover”, available free of charge at http://www.scirp.org/journal/PaperInformation.aspx?PaperID=50837.
Now IIRC, a month or two later Dr Roy Spencer published a guest piece on his blog saying that I’d got it wrong regards the change in cloud cover.
(Also, pay attention to the first part of the paper that shows ENSO changes can account for the historical global average temperature anomaly pattern from 1950 to 1987. So what if there’s a change in the dominant factor regards climate. To me it’s more absurd that a single factor gets blamed for all warming, regardless of whether it’s a period of a sharp upward trend or a period of a negligible warming trend.)
My mistake. It wasn’t a guest post that criticized my paper, it was a reader’s comment. My apologies to Dr Spencer if he felt that my comment above implied that it was of his doing.
Does anyone know of a study about Earth’s radiation to space in relation to reduced solar wind and reduced particles in space during extreme solar minimums? I tried a couple of quick searches, but didn’t find anything on this subject.
Love this discussion – its like watching some tortured creature writhing in a less-than-sweet torture or agony.
It simply will not venture anywhere near Dirt. Probably like in the time of Galileo and the Earth-centric model and how the religious establishment tried every which way to keep the Sun rotating around Earth.
So we have cosmic rays, oil on the water, this oscillation (no explanation of what causes it), *that* oscillation (again no cause is mentioned)
And of course the “Climate Is Always Changing”, usual used against Warmists as a way of avoiding further discussion – all the while not realising that saying that implies the existence of A God or Gaia. No wonder they’re driven nuts by Skeptix – the only possible retort to such a statement and Avoidance of The Issue is the Ad-Hom
If you want clouds, you need water.
Over the ocean, this is not a problem.
Over the land, it certainly can be.
Water exists (existed) over the land in many places and forms. There may be ponds, lakes, (peat) bogs, moors (Muirs), Carrs (peat bogs with trees)
Also there are plants, especially stands of trees, visible on the surface but for every ton of tree sticking up alive and well, there will (or SHOULD) be at least 10 tons of dead tree in the top 2 or 3 three feet of soil.
Likewise for grassland areas.
We know about that. We heard it from scientists researching Permafrost in Arctica and how it going to melt and create a(nother) Climate Catastrophe by turning into carbonoxide.
As any gardener or horticulturist will know (even a pot-plant on the windowsill will suffice), this dead (and alive) organic stuff retains water. It is after all made of water – one carbon atom to one water molecule and water has huuuuuge affinity for itself.
So far so good – lets venture out across the countryside and look for it. Remember, we’re looking for a layer of stuff like the Permafrost but not frozen solid.
But its not there is it.
And where are all the lakes and inland seas. We know they were there, just look at the roadside signposts and the names of the towns and villages.
Places with mere, moor, sey (sea) or Carr in their names. Places called Fen, previously underwater peat bogs
Where are they. All gone.
Why have they all gone?
To feed the people. Some televisual muppet popped up recently, in a repeat of an old documentary, to inform us that World Population had doubled in his lifetime. He was NOT a decrepit old f4rt with a stick in a wheelchair. Probably = 10 years less than me
It is the feeding of those people that has disappeared huge amounts of inland water resource and with has gone the clouds it would have craeted, with or without the help of Comsic Rayz, Milankovitch, endless oscillations ro dreaming notions that clouds somehow ‘shield’ you from The Cold.
What a crazy warped notion. Cold places are empty places, How do you ‘shield yourself’ from nothing. What sort of emanations come from ‘nothingness’
Of course it goes right back to childhood and the idea of someone/thing called Jack Frost – that he descended from cold clear skies and somehow made everything ‘frosty’
I used to believe that as a kid – I would put water filled glass jars and bottles out for him to play with.
Anyway, get the drift?
All these oscillations, oil-on-the-water, radiation rays and “Climate Always Changes” are *really* pathetic excuses to avoid the charge that Man, in the shape of (modern) farming has changed the water content of vast areas of land.
This has changed the clouds and set thermometers twitching.
Really really simple but NOBODY wants to go there do they because of the charges that will be levelled against them and THEY KNOW IT.
Its called Chickening Out. Sometimes = Appeasement.
A variation on Positive Feedback, something that NEVER has a happy ending.
But yes, it is one very tough nut to crack.
No matter, as long as the barley yield per acre or in total is still increasing, All Must Be Well With The World.
Or in fact also the yields of noxious & nutrient free starch, production of which dries out the dirt and creates deserts. An experiment that’s been repeated dozens of times through human history and what any Real Farmer will tell you
Deserts = Cold Places.
And *there* is something else the religious & School teachers & preachers have got All Wrong.
Hell is not a Hot Place as they assert,
Hell is a Cold Place
Not just farmers, city planners, builders and dwellers.
Recall: *every* year ‘we’ need at least 6 cities the size of London to accommodate New Arrivals
No matter, Cosmic Rays will ensure the weather in the city centre stays the same as it was inside the forest/grassland that was there previously.
We know that because a (super) computer adjusted itself and told us so.
And who is gonna argue with any computer, super or otherwise?
Or A Sputnik for that matter…..
There appears to be some problems with the ISCCP cloud cover dataset.
Identified in studies listed here…..
https://agwobserver.wordpress.com/2010/01/20/isccp-problems/
“The apparent decrease in global cloud cover has also been used as an argument against anthropogenic warming (but mainly outside of scientific literature). But when the sources of these arguments are consulted, almost without exception we run into ISCCP cloud cover data being used as the source. In the following, I will show you why it is false to claim global cloud cover trends based on ISCCP data.”
“It seems that the finding of Norris, Campbell, and Evan et al. about ISCCP satellite viewing angle (by changes in satellite network that affect the viewing angles) creating a spurious trend is a real problem. I think they have shown it beyond reasonable doubt. ISCCP website lists known and fixed errors in ISCCP data but there doesn’t seem to be any mention of this problem.
Many studies have made conclusions relating to clouds based on the apparent long term decrease in ISCCP data, but all that research is in doubt because the trend at least partly is not real. Furthermore, ISCCP cloud data is the longest satellite record we have on the subject, so it would be important to issue an official correction to this problem. When the trend is corrected, interesting things might be found, as shown by Clement et al. (2009) who corrected for the problem and found that cloud feedback is positive. As a long record, ISCCP data would be suitable to that kind of studies.”
The ISCCP website lists various problems and their corrections. See https://isccp.giss.nasa.gov/errors.html.
Of course you could have emailed Bill Rossow and asked him rather than just claimed that problems might exist.
I’ve been saying since this 2010 on the BBC blogs and at WUWT in 2012 https://wattsupwiththat.com/2012/08/20/spencers-cloud-hypothesis-confirmed/#comment-884789
Seems to me whilst Pinker stated she did not think cloud cover was responsible for rising temperatures, her 2005 paper clearly showed the link.
Observations: large areas of the ocean surface are smoothed by oil and surfactant pollution.
: En-route to Madeira a large smooth with meandering arms covered thousands of
square miles, with the smoothed areas resisting wave breaking up to force 4.
: https://seawifs.gsfc.nasa.gov/OCEAN_PLANET/HTML/peril_oil_pollution.html
An astonishing amount of oil is spilled every year.
: Tiny amounts of oil smooth large areas. (See Benjamin Franklin, Clapham Pond.
: The Mediterranean Sea is smoothed all along the Costa del Sol.
Conjecture: Fewer breaking waves reduces salt aerosol production
: Reduced mixing alters nutrient levels and disrupts the phytoplankton balance. Less
DMS production, fewer aerosols.
: Low nutrient tips phytoplankton populations towards more C4 and C4-like carbon
fixation. Reduced discrimination between C12 and C13, relatively more C13 pulled
down, a light carbon signature left in the atmosphere.
Predictions: Enclosed and polluted area of ocean – e.g. Med, North Sea, possibly Great Lakes
etc – will exhibit more surface warming than open ocean far from pollution sources.
: Diatom populations will persist later in the season
: Arctic ocean areas exposed to rivers flowing through oil production areas will exhibit
anomalous warming.
Observation: Until we research other causes of warming the pseudoscientists of the IPCC will continue to win.
JF
Again, is it a coincidence that Earth’s temperatures are bounded with a similar convergence as this curve?
The temperature of the equatorial Pacific area increased.
Please see
https://tambonthongchai.com/2018/11/02/spurious-correlations-in-time-series-data/
My theory on this is that clouds coverage reduces in response to increased CO2. Since it seems that if Ps/Pi is golden (1.618035), then the total fraction of surface emissions absorbed by the atmosphere can only be 2/(1 + g), where g is the golden ratio.
Since this ratio wants to be constant and increases CO2 increases absorption without clouds, fewer clouds are required to set absorption to what it wants to be. BTW, a small downward trend in cloud cover is also observed in the ISCCP cloud data.
The verdict is still out on Svensmark theory. The low average value solar parameters have just kicked in over this past year .
There has been no further global warming for the past two years ,still the big one for me is what overall oceanic sea surface temperatures do. That is the KEY, and thus far they are NOT cooling. That said they also have not made any further warming gains
It is wait and see.
That global cloud cover is a dominant modulating factor for GSAT should be apparent from first principles. This dictum also finds solid empirical support in the high coherence between local temperature anomalies and sunshine hours experienced at various well-run met stations around the globe. Without additional analysis Figure 1a, however, falls well short of providing strong evidence for this relationship. The overlying “plateaus” since ~175 months seem more a matter of graphic scaling than of demonstrated physical relationship.
Accumulating affects of clean air acts of 60’s, 70’s, 80’s in the west coupled with westerly winds reduce the amount of sulphate / particles in the northern hemisphere and then consequently reduce cloud nucleation of the water vapour carried alongside.
Could be. London stopped having “pea soup” fogs after coal was banned as a fuel for heating in London. A similar situation with other cities, so I’m told.
We clean up the air and more sunlight gets through. What a surprise (not)?
” Make hay while the sun shines”