Anthropogenic Climate Change: Circular Reasoning Run Wild?

[doogles]

Thanks TheVat for your comments. I agree with you totally when you say "Doogles, I believe sea level rise becomes more concerning when ice melting accelerates, as has happened to Alaska and Greenland in the past couple years. And Antarctica. When ice melts, the albedo of both land and sea drops considerably, and both absorb more heat that was formerly being reflected back into space by the ice. This causes a rapid acceleration in heat retention and that hastens further the melt rate. This kind of feedback can quickly add a huge volume of freshwater."

My concern of course is whether we are on the right track when we appear to be putting so much faith in the carbon dioxide thing.

I wasn't quite sure which Sections of the IPCC Reports you referred to, but I had another look through the Section headed IPCC Special Report on Climate Change, Desertification, Land Degradation, Sustainable Land Management, Food Security, and Greenhouse gas fluxes in Terrestrial Ecosystems Summary for Policymakers Approved Draft.

I may have been on the wrong page, but the UNBELIEVABLE aspect of all of those pages of advice is that it did not contain one word of control of population growth. It talks about the effects of Land Use on varying ranges of population densities, but if all of the land use is for the settlement and feeding of human beings, what is the use of all the fine tuning of land use if the population overtakes resources? I've mentioned this a couple of times back in other threads.

In any case, it's off topic. I should not have mentioned the fact that 46% of one group of Pacific Islands has actually increased in surface area over the last 19 to 60 years and that 14% have decreased, as judged by aerial and satellite photographs.

Back to the topic of whether reduction in cloud formation may be the main culprit in the increases of Average Global Near Surface Temperatures (AGNST), and even the possibility that cleaning the air and reducing the pollutants just MAY be the cause of reduced cloud masses since the 1970s and 80s.

Here are two references to reduced cloud if anyone is interested -- Olabode (2017; http://scifedpublishers.com/fulltext/as ... eria/21774) and Sanchez-Lorenzo et al (2017; https://www.nature.com/articles/srep41475). There could be many more.

I've located the main reference that the IPCC used for its cloud radiative forcing paragraphs and it makes an astonishing claim about the minor importance of carbon dioxide.

This is the Abstract of the article by Ramanathan et al 1989 referred to in the 2013 IPCC summary of clouds -- on this site https://science.sciencemag.org/content/243/4887/57. It was titled Cloud-Radiative Forcing and Climate: Results from the Earth Radiation Budget Experiment and published in Science 1989. The IPCC mentioned the parts of this Abstract up to the point where there was a balance of maybe -20 W/m2 net radiative forcing by clouds. But they did not mention the part highlighted below.

Abstract
"The study of climate and climate change is hindered by a lack of information on the effect of clouds on the radiation balance of the earth, referred to as the cloud-radiative forcing. Quantitative estimates of the global distributions of cloud-radiative forcing have been obtained from the spaceborne Earth Radiation Budget Experiment (ERBE) launched in 1984. For the April 1985 period, the global shortwave cloud forcing [-44.5 watts per square meter (W/m2)] due to the enhancement of planetary albedo, exceeded in magnitude the longwave cloud forcing (31.3 W/m2) resulting from the greenhouse effect of clouds. Thus, clouds had a net cooling effect on the earth. This cooling effect is large over the mid-and high-latitude oceans, with values reaching -100 W/m2. The monthly averaged longwave cloud forcing reached maximum values of 50 to 100 W/m2 over the convectively disturbed regions of the tropics. However, this heating effect is nearly cancelled by a correspondingly large negative shortwave cloud forcing, which indicates the delicately balanced state of the tropics. The size of the observed net cloud forcing is about four times as large as the expected value of radiative forcing from a doubling of CO2. The shortwave and longwave components of cloud forcing are about ten times as large as those for a CO2 doubling. Hence, small changes in the cloud-radiative forcing fields can play a significant role as a climate feedback mechanism. For example, during past glaciations a migration toward the equator of the field of strong, negative cloud-radiative forcing, in response to a similar migration of cooler waters, could have significantly amplified oceanic cooling and continental glaciation." Bear in mind also that at least one major climate researcher has produced evidence that the effect of carbon dioxide radiative forcing may be one third to one tenth of the currently accepted value in models.

This paper was published in 1989, seven years before the Kyoto Protocol, and provides significant quantification of the effects of clouds on climate. In addition, the three papers in one of my previous posts (that were published in 1995), also contain useful quantifications of cloud radiative effects. Curiously, I'm having difficulty in finding papers since then that provide quantification. I'm finding a number of articles of the style I've posted recently claiming words to the effect that clouds, water vapour and aerosols are currently the 'unknown factors' in 'Climate Change'. In addition, the Abstracts of their papers usually contain a spin to the effect that 'we have yet to clarify the uncertain effects of global warming on cloud behaviour'. The implication seems to be that carbon dioxide is causing 'global warming' (a very unscientific term in my opinion) which in turn is causing problems with clouds, water vapour and aerosols. One can't help but ask the same question that Neri posed in the OP - Anthropogenic Climate Change: Circular Reasoning Run Wild?

It appears that up till the time of the Kyoto Protocol, carbon dioxide was a minor player and clouds were a major player.

And now it seems we are doing our best to 'clean up our air'. As a by-product, are we actually reducing the very barrier (H2O Cloud) that has been keeping our AGNST at a moderate level???? Everyone is at liberty to read the above evidence for themselves and to form an opinion.

[TheVat]

It may be helpful to offer further clarification on the distinction between feedback and forcing:

Water vapor is one of the most important elements of the climate system. A greenhouse gas, like carbon dioxide, it represents around 80 percent of total greenhouse gas mass in the atmosphere and 90 percent of greenhouse gas volume.

Water vapor and clouds account for 66 to 85 percent of the greenhouse effect, compared to a range of 9 to 26 percent for CO2. So why all the attention on carbon dioxide and its ilk? Is water vapor the real culprit causing global warming?

The answer is that water vapor is indeed responsible for a major portion of Earth’s warming over the past century and for projected future warming. However, water vapor is not the cause of this warming. This is a critical, if subtle, distinction between the role of greenhouse gases as either forcings or feedbacks. In this case, anthropogenic emissions of CO2, methane, and other gases are warming the Earth. This rising average temperature increases evaporation rates and atmospheric water vapor concentrations. Those, in turn, result in additional warming.

The primary reasons why water vapor cannot be a cause of climate change are its short atmospheric residence time and a basic physical limitation on the quantity of water vapor in the atmosphere for any given temperature (its saturation vapor pressure). The addition of a large amount of water vapor to the troposphere would have little effect on global temperatures in the short term due to the thermal inertia of the climate system. The Earth’s thermal inertia, largely due to the enormous amount of water covering two thirds the planet’s surface, is the primary reason why half the Earth does not freeze over every night and bake every day. As a result, different areas warm over the course of years (for land surface temperatures), decades (for ocean surface temperatures), and even centuries (for deep ocean temperatures and ice sheets).

For the troposphere to sustain higher absolute humidity requires an increase in air temperature. Water vapor cannot itself catalyze temperature increases in the short time (estimated at around 10 days) that a discrete water vapor influx would remain before precipitating out. A sustained increase in tropospheric water vapor requires a strong external forcing to provide the initial temperature increase.

In general, the amount of water vapor in the troposphere does not vary significantly over time so long as temperatures remain stable. However, if some external forcing causes tropospheric temperatures to increase, there will be a water vapor feedback. Warmer air can sustain a higher absolute humidity than cooler air. Furthermore, warmer temperatures tend to (but do not always) increase evaporation rates, leading to a higher concentration of atmospheric water vapor. This feedback acts in a number of different and at times contradictory ways....

https://www.yaleclimateconnections.org/ ... eedback-2/

[doogles]

I hope nobody formed the impression that I was talking about water vapour. I appreciate the input from TheVat, but his response makes me think that I may have not expressed myself clearly enough or else I have misconstrued the meaning of some of the research workers I have cited. All of the authors I have cited were talking about the accumulations of physically visible fine droplets of water or ice known as clouds, as a reflective barrier to solar radiation, and not water vapour.

The last reference I cited (by Ramanathan et al 1989) was the main one used by the IPCC to explain the physical science basis of cloud radiative effects. Just to save you going back through the posts, I wrote "And to put the radiative effect of clouds into this perspective, I'll cite the IPCC 2013 report by Stocker et al in Climate Change 2013: The Physical Science Basis. Contribution of Working Group I to the Fifth Assessment Report of the Intergovernmental Panel on Climate Change. -- " Page 580 7.2.1.2 Effects of Clouds on the Earth’s Radiation Budget -- "The effect of clouds on the Earth’s present-day top of the atmosphere (TOA) radiation budget, or cloud radiative effect (CRE), can be inferred from satellite data by comparing upwelling radiation in cloudy and non-cloudy conditions (Ramanathan et al., 1989). By enhancing the planetary albedo, cloudy conditions exert a global and annual shortwave cloud radiative effect (SWCRE) of approximately –50 W m–2 and, by contributing to the greenhouse effect, exert a mean longwave effect (LWCRE) of approximately +30 W m–2, ... "

I am not a climate scientist; I have quoted climate scientists. I realise that I could have misinterpreted the purport of their meanings, so I will not be offended if any of you can point out any case wherein I have done this. On the contrary, I would appreciate it, because it is important to me that I finish up with a properly-balanced view on all matters in my mind.

I'll stick my neck out and attempt to summarise what I've been attempting to say after researching the very basic literature of this 'global warming' philosophy.

1. I believe that the carbon dioxide role in increased AGNST is based on extremely poor basic science. I did find a couple of references to absorptive properties of greenhouse gases since Tyndall. But they had nothing to do with the absorptive and radiative properties of infrared radiation by carbon dioxide. The carbon dioxide theory appears to be built on very flimsy theories, has involved changes of the economic practices of many countries, and after 23 years has had no visible effects on the curve of atmospheric concentration of carbon dioxide by year -- after 23 years (Yes. I know that some countries are producing as many more emissions that exactly compensate for those emissions that the others are reducing.)

2. The cooling effect from the 1940s to the 1970s and 1980s, in spite of steady increases in carbon dioxide, defies the principle that carbon dioxide is a main player in increasing AGNST. It makes more sense to regard the gross particulate matter and sulphates from a few volcanoes in that period, but more importantly, there was an industrial output of particulate matter and pollutant gases (sulphur dioxide and nitric oxide) that enhanced CLOUD formation. All worked as barriers to solar radiation reaching the surface of the planet. I've mentioned a couple of references in a previous post to a reduction of cloud cover from the 1970s and 1980s, since the emissions have been controlled by the then newly formed Environmental Protection Authorities and Agencies. The evidence is there. I believe that any hypothesis of the reasons for our increase in AGNST, has to include a plausible explanation for this cooling from 1940 to 1970. The carbon dioxide theory fails to my mind. Cloud and particulate matter acting as barriers to solar radiation work.

3. I've listed some articles from 1989 till 1995 that provide measured amounts of cloud radiative reflection, compared with radiative feedback suggesting that clouds play a major role in keeping our planet at a slightly cooler near surface temperature. I've also listed a number of articles since the Kyoto Protocol that seem to cautiously state words to the effect that clouds are the unknown quantity in 'climate change'. It's almost as if researchers since 1996 are afraid to say anything contrary to the carbon dioxide faith.

4. I've suggested that anyone reading this should consider the possibility that in cleaning up our emissions, we may have been inadvertently reducing our cloud barrier and thus allowing more solar radiation at planetary surface level. This of course manifests as increased AGNST readings. I believe our planetary future requires something more solid than a religious-type faith in a carbon dioxide philosophy.

I've left myself wide open to criticism. At least have a think about it, but please don't present evidence based on faith.

[charon]

-

I don't know about water vapour (water vapour?) but, as I understand it, climate change is about carbon emissions (CO2) and their increasing and potentially disastrous effect on the earth's atmosphere.

A certain amount of 'greenhouse effect' is necessary to keep the earth warm but when the levels become excessive then global warming takes place. Even an increase of half a degree is dangerous and results in extremes of weather events.

It's no surprise that most of these new events have taken place in the last 150 years since the advent of industrialisation and deforestation. And they are obviously happening now.

Those in the know have been shouting for some time and you'd think it's time we woke up. The US and China are apparently the worst culprits in global terms... and Trump pulls out of the Paris agreement. I don't know about China.

We all know that politics is run on money. If politicians are only concerned with improving the economy of their country then they won't listen to anything that might threaten industry and profit. At least, that's the way it strikes me.

For the rest, the EU are vaguely talking about some plan or other to happen by 2050. That's 30 years away. There's also the effect on nature - crops and those animals whose habitats have been destroyed.

We really are the most appallingly stupid species ever invented.

[TheVat]

Dooogles, if you've studied the links I have posted, you would have found adequate explanatory material on how water vapor AND droplets (clouds are functional equivalent of water vapor, and trap heat at night, as well as adding thermal mass to store heat) is

A. a feedback, not a forcing, effect of GHG induced warming

B. a GHG, in its net effect, and therefore a feedback effect when other GHGs rise in ppm

(IIRC, Bangstrom also posted useful insights on this. )

C. Has a feedback effect whether as diffuse vapor or concentrated in droplets, i.e. cloud masses

Since I, and other people in the sciences, have presented data in many other threads here that also addresses the 1940-70 slight cooling, I will not keep rehashing that. Sulphate aerosols work a bit differently, and all are welcome to do the research into that.

Also, bear in mind that the average rise in surface temps has been much higher over the 25% of the planet's surface which is land. Oceans absorb more heat and large thermal masses of water are slower to warm. Daytime cloud cooling at the surface is also less over land. And land is where we humans live.

Please let us know of future research that you find in peer-reviewed sources. I appreciate your respect for the methods of science and look forward to interesting findings as they come along.

[doogles]

With respect, TheVat (and I do respect your inputs), I do read references in response to my posts, but for obvious reasons, I won't read suggested books. On one occasion some years ago I uploaded approximately 15 references from a respondent, supposedly refuting something I'd said, only to find that they were all on a different aspect of the topic under discussion.

I have another small problem at times as well when I get a reference (only) to a website such as " * https://www.ipcc.ch/srccl-report-download-page/ The summary is the first pdf, at top of list." On this occasion I found 41 pages on An IPCC Special Report on climate change, desertification, land degradation, sustainable land management, food security, and greenhouse gas fluxes in terrestrial ecosystems. I read through the document looking for the pertinent items without success.

Please take this as a positive suggestion rather than a negative criticism. It would be much easier if people cited a website and added a small amount of paraphrasing to indicate the thrust of that site, firstly to ensure that it is the correct material that one is reading, and secondly to ensure it is relative to the point being made.

Obviously, you and I have a different concept of clouds and water vapour. My concept of water vapour is that it is an invisible molecule of H2O, and that clouds are accumulations of visible fine water or ice droplets. The first is a greenhouse gas that absorbs longwave radiation. The second consists of physical particles that reflect and deflect incoming solar radiation. Both absorb some of the radiation as greenhouse gases. While clouds are generally estimated to cover 60 to 70% of the planet, while water vapour is invisible and very variable in concentration. Feel free to point out the error of this view.

My understanding of water vapour and water droplets (the basis of clouds) comes from the following type of information -- http://meteorologytraining.tpub.com/142 ... 269_43.htm -- "Hygroscopic nuclei are small particles on which water vapor can condense or sublime. Hygroscopic nuclei actually attract water vapor. The most effective hygroscopic nuclei are the by-products of combustion, sulfuric acid and nitric acid particles, and salts (such as sodium chloride raised from the sea surface). Dust particles may contain sufficient salts or acids to become hygroscopic nuclei, but dust particles in general are not effective hygroscopic nuclei. The presence of hygroscopic nuclei is a must for water vapor to condense. Air has been super-saturated in laboratories to over 400% before condensation began in the absence of hygroscopic nuclei. "These hygroscopic nuclei have been disappearing since the EPAs started cleaning up the air from the late 60s to 80s.

And so have the clouds. I'll mention again the two references I've located so far -- Olabode (2017; http://scifedpublishers.com/fulltext/as ... eria/21774) and Sanchez-Lorenzo et al (2017; https://www.nature.com/articles/srep41475). There could be many more. And I will endeavour to locate more.

Fair enough, if enough CO2, CH4 and N2O build up in the atmosphere, the extra energy they retain results in more evaporation of water vapour, and this in turn then acts as a more efficient greenhouse gas making the atmosphere warmer still. But in spite of this effect, the loss of cooling due to a diminution of clouds just may be producing more energy in the surface atmosphere than the greenhouse effect. That article by Ramanathan et al (1989) seems to suggest this to me. Could I ask readers to have another look at what Ramanathan said and tell me whether I have made a gross error in interpretation. Please don't take me seriously, but the future of the world may depend on it (Apologies; couldn't help myself) As if!! I'd still like to know what others think. I really would have liked some feedback on this article and please bear with me if I mention it one last time.

Ramanathan et al (1989; https://science.sciencemag.org/content/243/4887/57 ). Remember that the findings of this article have been cited by the IPCC. The aauthors used data from the Earth Radiation Budget Experiment which used several satellites for the data. On pages 61-62 of the article, they summarise the Climatic Implications. They state "Cloud forcing reduces the absorbed solar radiation by 44.5 W/m2 and the LW emission to space by 31.3W/m2 when averaged over the globe (Tables 2 and 3). Thus, globally, clouds reduce the radiative heating of the planet by 13.2 W/m2 (Table 3). This conclusion is based on data from just 1 month. Data for July 1985, October 1985, and January 1986 are now being processed. Preliminary analyses of these months confirm the basic finding of this study: clouds have a net cooling affect on the global climate. There are significant month-to-month differences in the net cooling effect. It attained a maximum value of -21.3 W/m2 in January 1986 (Table 3) ... Several studies have suggested that radiative heating of a mere 4W/m2 resulting from a doubling of CO2 concentrations in the atmosphere would lead to a global warming of 3.5 to 5 K (4). The negative cloud-radiative forcing is three to five times as large as the doubled CO2 forcing. [color=#FF0000]The size of the forcing suggests that the planet would be significantly warmer without the current cloud-radiative forcing." [/color]I'm assuming these figures represent end measurements that have come about regardless of all of the possible complicated co-factors that could have affected them.

As I said, I am not a climate scientist, but I'm left with the impression that these researchers are saying that clouds have a net cooling effect on the global climate of an average -15 W/m2, and that the planet would be warmer without the current cloud radiative forcing. The question is whether I am wrong in this interpretation.

So far nobody has commented on this experiment in its own right.

[TheVat]

That all makes sense. Over mid and high latitude oceans, clouds have a net cooling effect that would somewhat mitigate the overall rise in temp due to GHG forcing. This is not inconsistent with what I've gleaned about the GH effect of water vapor, or the net warming effect of clouds over land and in the tropics. I would speculate that overnight cloud cover is more persistent in the tropics, due to warmer air that can hold more moisture before saturation is reached and precipitation occurs. Basically the finding shows a mitigation effect from the diurnal pattern of cloud formation at higher latitudes, where skies are more tending to clear as night cools. This does seem to shift the balance to the high albedo daytime effect.

This would lend further support to the view that GHG effects on temps will be more severe on land, where humans dwell. That does match the data so far, and you won't find too many farmers or ranchers here in N America who would dispute it.

Doogles, this is helpful....have other researchers followed up on Ramanathan et al more recently?

[doogles]

Thanks TheVat. I'll see what comes up in the next couple of days

[doogles]

Thank you TheVat for the comments. You ask " ... have other researchers followed up on Ramanathan et al more recently?"

That is something that puzzles me. This paper by Ramanathan et al (1989) and three others from 1995, all mention quantifications of cloud forcings, but since then, almost every paper I have come across seem to cautiously state words to the effect that clouds are the unknown quantity in 'climate change'. They also tend to put a spin on their conclusions to the effect that 'global warming' may be having some effect on clouds.

Noting a possible change in attitude by researchers over time, I did a search for the period 1989 to 1996 and found the following.

1989-1996

Also in 1989, the same year as Ramanathan's paper, Wigley (1989; https://www.nature.com/articles/339365a0) Abstract -- "It has been hypothesized that climate may be noticeably affected by changes in cloud condensation nuclei (CCN) concentrations, caused either by changes in the flux of dimethylsulphide (DMS) from the oceans1,2 and/or by man-made increases in the flux of sulphur dioxide (SO2) into the atmosphere3. When oxidized, the sulphur compounds produce non-sea-salt sulphate (n.s.s.-SO2−4,) aerosols, which may act as CCNs. The CCN changes affect climate by altering the number, density and size distribution of droplets in clouds, and hence their albedo. Here I am concerned primarily with the possible effects of SO2. Because the increase in SO2 emissions has been largely in the Northern Hemisphere, this raises the possibility of a cooling of the Northern Hemisphere relative to the Southern3. By comparing observed differences in hemispheric-mean temperatures with results from a simple climate model, one can place limits on the possible magnitude of any SO2-derived forcing. The upper limit is sufficiently large that the effects of SO2 may have significantly offset the temperature changes that have resulted from the greenhouse effect." Remember that Ramanathan suggested that the net negative cloud forcing may exceed the positive effect of doubling the carbon dioxide manifold.

Arking (1991; https://journals.ametsoc.org/doi/abs/10 ... -0477(1991)072%3C0795:TREOCA%3E2.0.CO;2) conducted a review of the literature at the request of the Radiation Commission of the International Association of Meteorology and Atmospheric Physics (IAMAP) to establish an overview of key results published over the last 15 or 20 years, along with some relevant unpublished model studies. The focus is on 1) the impact of clouds on the incoming and outgoing radiation at the top of the atmosphere, and 2) the two-way interaction of clouds with other variables of the climate system—i.e., the cloud/climate feedback problem—as revealed by climate model simulations. Excerpts from the Abstract include "There is general agreement that the annual global mean effect of clouds is to cool the climate system, but there is significant disagreement on magnitude, with the two' investigations based on recent satellite data indicating a range from 17 to 27 W/m2.", " Sensitivity of clouds to cloud condensation nuclei raises the issue of a more direct role of clouds in climate change, where aerosols associated with S02 emissions can ultimately lead to brighter clouds and a reduction in solar heating." " On cloud feedback in climate simulations, there are wide discrepancies amongst models." Please note the second excerpt suggesting that sulphur dioxide could have been associated with 'brighter clouds' (more droplets reflecting and deflecting more solar radiation).

Hartmann and Doelling (1991; https://agupubs.onlinelibrary.wiley.com ... /90JD02065) also investigated the effect of clouds using data from the Earth Radiation Budget Experiment (ERBE). You'll remember that this was the same satellite program and data sets used by Ramanathan. They measured the net radiative effectiveness of clouds using the magnitude of outgoing longwave radiation and on reflected solar radiation to determine the net radiative effectiveness of clouds. Both estimates of the cloud radiative effectiveness indicate that the global average net radiative effect of today's clouds is cooling, with the decrease in absorbed solar greater than the decrease in outgoing longwave radiation. The ratio of the solar to the longwave effect of cloud is about 1.85 based on the regression method and 1.55 based on the comparison of clear‐sky and average radiation budget climatologies.

The ERBE system of satellites was replaced by a new set referred to as CERES round about 1990.

Cess et al (1995; https://science.sciencemag.org/content/267/5197/496) Abstract -- "There has been a long history of unexplained anomalous absorption of solar radiation by clouds. Collocated satellite and surface measurements of solar radiation at five geographically diverse locations showed significant solar absorption by clouds, resulting in about 25 watts per square meter more global-mean absorption by the cloudy atmosphere than predicted by theoretical models. It has often been suggested that tropospheric aerosols could increase cloud absorption. But these aerosols are temporally and spatially heterogeneous, whereas the observed cloud absorption is remarkably invariant with respect to season and location. Although its physical cause is unknown, enhanced cloud absorption substantially alters our understanding of the atmosphere's energy budget."

Rather than go through hundreds if not thousands of papers over the next 20 years I jumped to literature dated from 2013.

2013-2019

This one seemed out of place with the thrust of the earlier ones and I put it in for the record -- Hartmann (2016; https://www.pnas.org/content/113/32/8897.short) " ... An advance was made in the most recent report of the Intergovernmental Panel on Climate Change, which concluded that cloud feedback is likely positive, meaning that the response of clouds to climate change acts to increase the magnitude of the surface temperature change (3). This consensus is based in part on the development of basic physical understanding of why high clouds get higher (4) and low clouds decrease their area coverage in a warmed climate (5, 6). In PNAS, Bony et al. (7) propose a basic thermodynamic mechanism that may cause the temperature profile to become more stable in the upper troposphere when the Earth warms. They expect this stabilization to cause anvil cloud area to decrease in a warmed climate, although they conclude that the effect of this anvil area reduction on cloud feedback is uncertain." It was decided by some sort of consensus; not basic science measurements. I could not find this mention in the IPCC report on clouds, but I will have something to say on the IPCC recommendations later.

The next lot seemed to lack quantification and all seemed a bit wishy-washy in that they all seemed to suggest uncertainty about clouds and climate change.

Stocker et al (2013; https://agupubs.onlinelibrary.wiley.com ... 18GL081871) -- " ... Unfortunately, the extent to which the myriad of possible climate feedbacks influences Arctic amplification is currently plagued with uncertainty. This is especially the case for cloud feedbacks, which continue to be the leading cause of uncertainty in climate projections. "

Ying and Thompson (2019; https://journals.ametsoc.org/doi/full/1 ... -18-0417.1) -- " ... there is still considerable uncertainty about the underlying mechanisms, whereby CRE (Cloud Radiative Effects) govern the jet response to climate change."

Nuijens and Siebesma (2019; https://link.springer.com/article/10.10 ... 19-00126-x) -- " Clouds in nature are more complex than the idealized cloud types that have informed our understanding of the cloud feedback. Remaining major uncertainties are the coupling of clouds to large-scale circulations and to the ocean, and mesoscale aggregation of clouds."

Hentgen et al (2019; https://agupubs.onlinelibrary.wiley.com ... 18JD030150) -- " Although crucial for the Earth's climate, clouds are poorly represented in current climate models, which operate at too coarse grid resolutions and rely on convection parameterizations."

Sancho-Lorenzo et al (2019; https://www.nature.com/articles/srep41475 -- "Clouds affect the global energy balance as they reflect a large fraction of the Sun’s incoming radiation and at the same time absorb and emit longwave radiation1,2. Despite their relevance, large uncertainties remain with respect to the response and feedbacks of the clouds to anthropogenic forcing. Consequently they are considered as one of the main sources of uncertainty for climate sensitivity and future climate scenarios3,4,5."

Those that investigated reduced cloud as a cause of possible increased surface solar radiation seemed more positive.

Reduced cloud literature

Sanchez-Lorenzo et al (2017; https://www.nature.com/articles/srep41475) Abstract "Here we report a widespread decrease in cloud cover since the 1970 s over the Mediterranean region, in particular during the 1970 s–1980 s, especially in the central and eastern areas and during springtime. Confidence in these findings is high due to the good agreement between the inter-annual variations of cloud cover provided by surface observations and several satellite-derived and reanalysis products, although some discrepancies exist in their trends. Climate model simulations of the historical experiment from the Coupled Model Intercomparison Project Phase 5 (CMIP5) also exhibit a decrease in cloud cover over the Mediterranean since the 1970 s, in agreement with surface observations, although the rate of decrease is slightly lower. The observed northward expansion of the Hadley cell is discussed as a possible cause of detected trends."

Kambezidis et al (2016; https://www.sciencedirect.com/science/a ... 2616303145) Partial Abstract; " … Although several studies have examined the solar radiation trends over Europe, North America and Asia, the Mediterranean Basin has not been studied extensively. This work investigates the evolution and trends in the surface net short-wave radiation (NSWR, surface solar radiation - reflected) over the Mediterranean Basin during the period 1979–2012 using monthly re-analysis datasets from the Modern Era Retrospective-Analysis for Research and Applications (MERRA) and aims to shed light on the specific role of clouds on the NSWR trends. The solar dimming/brightening phenomenon is temporally and spatially analyzed over the Mediterranean Basin. The spatially-averaged NSWR over the whole Mediterranean Basin was found to increase in MERRA by +0.36 Wm−2 per decade, with higher rates over the western Mediterranean (+0.82 Wm−2 per decade), and especially during spring (March-April-May; +1.3 Wm−2 per decade). However, statistically significant trends in NSWR either for all-sky or clean-sky conditions are observed only in May. The increasing trends in NSWR are mostly associated with decreasing ones in cloud optical depth (COD), especially for the low (<700 hPa) clouds. The decreasing COD trends (less opaque clouds and/or decrease in absolute cloudiness) are more pronounced during spring, thus controlling the increasing tendency in NSWR. The NSWR trends for cloudless (clear) skies are influenced by changes in the water-vapor content or even variations in surface albedo to a lesser degree, whereas aerosols are temporally constant in MERRA. The slight negative trend (not statistically significant) in NSWR under clear skies for nearly all months and seasons implies a slight increasing trend in water vapor under a warming and more humid climatic scenario over the Mediterranean.

Pfeifroth et al (2018; https://www.researchgate.net/publicatio ... _in_Europe) Abstract -- "Solar radiation is the main driver of the Earth's climate. Measuring solar radiation and analysing its interaction with clouds are essential for the understanding of the climate system. The EUMETSAT Satellite Application Facility on Climate Monitoring (CM SAF) generates satellite-based, high-quality climate data records, with a focus on the energy balance and water cycle. Here, multiple of these data records are analyzed in a common framework to assess the consistency in trends and spatio-temporal variability of surface solar radiation, top-of-atmosphere reflected solar radiation and cloud fraction. This multi-parameter analysis focuses on Europe and covers the time period from 1992 to 2015. A high correlation between these three variables has been found over Europe. An overall consistency of the climate data records reveals an increase of surface solar radiation and a decrease in top-of-atmosphere reflected radiation. In addition, those trends are confirmed by negative trends in cloud cover. This consistency documents the high quality and stability of the CM SAF climate data records, which are mostly derived independently from each other. The results of this study indicate that one of the main reasons for the positive trend in surface solar radiation since the 1990's is a decrease in cloud coverage even if an aerosol contribution cannot be completely ruled out." Note that these figures are only from 1992; if data had been available, the trend may have been much more marked.

A graph (probably at the end of this post; my 'place in line' is not working) shows this inverse relationship between surface solar radiation and cloud fractional coverage.

Paudel et al (2019; https://www.scirp.org/journal/paperinfo ... erid=90428) concluded that "Changes in cloud, both in the fraction of sky covered and in their radiative characteristics, played a major role in determining the global radiation measured in Israel during the last 60 years. Highly significant inverse linear relationships between normalized solar energy reaching the surface (Eg↓) and cloud cover indicate that a reduction in cloud transmission occurred in both the central coastal plain and central mountain region with a much smaller change in the transmission of cloudless skies. Analysis by stepwise regression indicated that since 1970 changes in cloud cover accounted for 61% of the changes in Eg↓ while the major increase in local fossil fuel consumption, serving as a proxy for anthropogenic aerosol emissions, only accounted for an additional 2% of the changes. Although the interaction between cloud cover and fossil fuel consumption is not statistically significant the indirect aerosol effect demonstrated in this study suggests that an important microphysical interaction may exist."

I think that's enough to make the point. There are mountains of publications available.

What I found interesting was that the IPCC in its 2013 document appears to be making serious recommendations about cloud whitening, using sulphur dioxide at stratospheric level. It would make interesting Sunday reading -- See https://pure.mpg.de/rest/items/item_200 ... 48/content -- Section 7.7 Solar Radiation Management (SRM)and Related Methods. There are many considerations and the following excerpt is just a very small sample. Remember the suggestions of the five Copenhagen Consensus Centre economists about cloud whitening. Here is one small excerpt " 7.7.2.1 Stratospheric Aerosols Some SRM methods propose increasing the amount of stratospheric aerosol to produce a cooling effect like that observed after strong explosive volcanic eruptions (Budyko, 1974; Crutzen, 2006). Recent studies have used numerical simulations and/or natural analogues to explore the possibility of forming sulphuric acid aerosols by injecting sulphur-containing gases into the stratosphere (Rasch et al., 2008b). Because aerosols eventually sediment out of the stratosphere (within roughly a year or less), these methods require replenishment to maintain a given level of RF. Research has also begun to explore the efficacy of other types of aerosol particles (Crutzen, 2006; Keith, 2010; Ferraro et al., 2011; Kravitz et al., 2012) but the literature is much more limited and not assessed here. The RF depends on the choice of chemical species (gaseous sulphur dioxide (SO2), sulphuric acid (H2SO4) or sprayed aerosols), location(s), rate and frequency of injection."

I think it's ironic that we have been clearing our fossil fuel emissions of SO2 and N2O, and now (well at least 6 years ago) the IPCC was considering injecting SO2 back into the stratosphere to produce more cloud.

[doogles]

After my last post, it occurred to me that there was not a suitable legend attached to the graph above and yet this graph, although applicable to clouds in some parts of the Mediterranean area only, just may contain a story about the physical aspects of 'climate change' in a large portion of our planet. It covers a time range from 1992 to 2015 only, but I feel that the differences would have been more marked if such data had been available from 1970 to 1980.

The two blue lines show the Cloud Fractional Coverage of the sky (CFC - Right Vertical Axis) in terms of percentage change from the average over the period of measurements. The first point is that two independent systems (Clara and Comet) showed very similar tracings -- and this gives some authenticity to the readings. The extreme swings cover a range of about 6% change (from -3 to +3), with an average of say roughly 3%.

The yellow tracing shows the changes in surface solar radiation (SSR) from the mean in that area, measured by a system called Sarah-2. As you can, there is almost a perfect negative correlation of this yellow tracing with the light- and dark-blue CFC tracings. As the cloud cover decreased, the amount of solar radiation detected at the Earth's Surface increased -- by an extreme of 8 Watts per square metre (-5 to +3) with say roughly an average of 4 Wm#2.

So that in roughly 25 years, the cloud fractional cover over the Mediterranean has decreased by roughly 3% and the solar radiation at ground level has increased by roughly 4 Wm#2.

The red tracing is of the change from a mean value of the amount of radiation detected at the Top of the Atmosphere (TOP) and as you can see, this is almost a classic inverse of the extra amount detected at the surface (yellow tracing). They almost counteract one another in the sense that the radiation detected at the ground level of our planet is higher when that at the top of the atmosphere is lower -- which suggests that diminished clouds are allowing more sunlight to reach ground level.

A feet-on-the-ground question -- Who among us doesn't feel cooler on a sunless day when clouds come over?

This increase of surface solar radiation of roughly 4Wm#2 for a 3% decrease in cloud fractional coverage could possibly be put into a perspective when one considers that carbon dioxide has a radiative forcing of 1.6 Wm#2.

The 'cloud' situation obviously presents a conundrum for the IPCC and the EPAs of the world. The more we clean up the atmosphere of pollutants, the more we remove potential hygroscopic nuclei for cloud production, the less cloud barrier we have to solar radiation, and the more surface solar radiation we receive at the surface. We finish up with higher average global near-surface temperatures. And the effect caused by this reduction of cloud formation seems to be greater than that caused by increases in carbon dioxide, as Ramanathan et al said 30 years ago -- Yes, 30 years ago. It's a losing battle, unless we do something to increase cloud formation.

Theorettically, we could stop current methods of burning fossil fuels in a clean manner, but not only would we have the old smogs and atmospheric particulate matter back, but the reality is that fossil fuels are a non-renewable limited resource.

So, do we need research into 'cloud whitening' as a priority for economic or survival reasons?

The above may explain why I was interested in Neri's OP about the importance of clouds and of course why I was pleased to hear his news that an experimental cloud research was active at CERN.

I'm amused at the protesters here in Queensland at the moment. Full approval has been given for the establishment of the Adani coalmine. Protesters are blocking traffic at peak hour here in Brisbane, to the gross annoyance of commuters, in addition to obstructing heavy machinery at the site of the mine. I would be surprised if a single one of them has questioned or investigated for themselves the wisdom of the current carbon dioxide philosophy. They have put their faith in the carbon dioxide reduction theory. The sad thing to my mind is that many of them are willing to go to gaol in the cause of 'saving the planet', but in effect it may be beneficial in the immediate term to burn more fossil fuel to produce more cloud cover, while we try to work out some practical ways of increasing cloud cover.

[charon]

Just stop polluting the atmosphere and knocking down trees. Start there.

[doogles]

The thrust of the last two evidence-based posts Charon, has been that it has been the successful removal of sulphurated and other pollutants from the air, that has resulted in reduced cloud. And it is this reduced cloud that has been the main driver of increasing average global near-surface temperatures - more so than carbon dioxide.

The IPCC is now considering how to re-inject more sulphurated compounds into the stratosphere to reverse the loss of cloud. The references were listed and the relevant section cited in the second last post. You don't even have to look up the website. It is there for you to read.

Do you have any evidence-based ideas on how to selectively remove pollutants without removing sulphurated compounds?

[charon]

I see my big yawn has been removed.

You just don't see it, do you? First they do something really stupid like spewing industrial waste into the atmosphere we breathe and which sustains us.

Then they think of some smart-arse way round it by injecting even more chemicals to reduce the problem... thereby creating an even bigger one. We are STUPID, get it?

What you're saying, dressed up as clever science, is carry right on polluting the atmosphere then screw the whole thing up even more by trying solve it without stopping what caused it in the first place.

We're always doing this. We don't tackle and remove the causes, we just launch into a series of reactions which create other problems, then react to those, then react to those again and again till the whole thing becomes impossible.

Stop polluting the atmosphere. Stop destroying rainforests which are the lungs of this planet. And when the politicians and business people start whining about their economy tell them they should have thought of that in the first place.

I'm no tree-hugger but I see what's in front of us. What do you think turned Beijing into this? We all know what it was and it's all man-made.



You and I may be long gone soon so it's not us who'll suffer the worst of it, it'll be our children and their children (luckily I haven't got any children but the point is there).

You can play sulphur games all you like but you're tinkering with symptoms, not root causes. And the real root causes are our blind imbecility, greed, and total lack of care about anything except utilitarian profit.

Don't you wish I'd just yawned and left it there?