Comments 1 to 28:

1. BilB at 08:06 AM on 4 September, 2017

   Good John Hartz article, and good to see terms such as "energy in the atmosphere" entering the conversation. 

   What is missing in this article is the reason why, or how, the "energy in the atmosphere" makes a difference. 

   It is all about density.

   The 60's high school science that I grew up with, and take note here that this includes the bulk of the baby boomers who are commanding the bulk of the world's wealth and political power, was that storms are caused by the sun's energy warming air which rose carrying moisture with it to form rain. I now believe that this is demonstably a false understanding of how rain making works (I hasten to add that I am not a scientist and this is entirely guesswork on my part). The percep[tion that hot air causes storms has been utilised by the denialists to obfuscate the real atmospheric processes, as they concentrate on the notion that Global Warming will result in ever higher daytime air temperatures, which we know full well is not the case and Gabriel Bowen points to what really happens.

   The one piece of knowledge that is missing from general public knowledge is that humid air is lighter than dry air, it is all about relative density. It turns out that high humidity air, although only a little bit lighter than dry air has a very large uplift capacity relative to warm air. In fact by my back of the envelope calculations it takes a 20 degree C difference in dry air to equal that humid air uplift capacity. 

   So what we see in the environment is thermal energy creating uplift and this level of uplift gives us the spotted fluffy clouds of a standard summers day where the uplift rises to a level where there is a temperature and density barrier which causes the moisture in that air mass to begin to condence into larger droplets and the air energy is expended in turbulent air movement and infra red radiation, but no rain formation. It only dawned on me recently what mists and clouds are about when I drove through a morning mist near my business premisis. A mist is where the moisture forms droplets large enough for the uplift effect of the density difference to balance out and the moisture cannot rise until more energy is delivered with the morning sun, else bigger droplets form causing dew (we often sense a warmth from such air as the latent heat of condensation warms the carrying air). 

   My conclusion is that rain clouds are formed not by thermal up lift but by humidity uplift. It was not until I realised this that I understood why there can by storms in sub arctic environments. 

   So the full story is that Global Warming delivers heat to the oceans (and the land) thereby increasing the average air moisture content. This moisture content moderates the average air temperature and the increase in average air temperature is predominately visible in the average night time temperature, ie as the average night time temperature increases it is seen as the time of the early morning at which the temperature begins to fall (later and later as Global Warming intensifies and invisible to most people who are generally asleep and do not experience the time of change). 

   Climate Change is predominately the impact of the increase in atmospheric energy in the form of atmospheric moisture, and the primary driver of how that makes a difference is the relative density of moist air over dry air. The density difference creates the atmospheric overturning effect and volume of the moisture both increases that effect and causes the increase in rain volume that we are seeing around the globe.

   The simple message is that CO2 increase is the primary driver of Global Warming and moist air increase density difference is the primary driver of Climate Change.

   It would be interesting to know if Judith Curry and her cohorts understood this important point.

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2. Swayseeker at 22:24 PM on 4 September, 2017

   To answer the comment re density of air and water vapour content: At a temperature of 40 deg C with RH of 30% and P=101.325 kPa, air has a density of about 1.118 kg/cubic metre. If you raise the RH of this air to 90% it has a density of about 1.099 kg/cubic metre. This is the same as air with an RH of 30% and T=45 deg C. By increasing the RH of the air with RH = 30% to one with RH = 90% (all at T=40 deg C) you have about the same effect on density as raising the temperature of the air by 5 deg C ( from 40 to 45 deg C).

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3. Bob Loblaw at 23:49 PM on 4 September, 2017

   BillB:

   Please read about the law of partial pressures, and how well-mixed gases do not behave as independent fluids. Water vapour is just another component of air, affecting the density of air but not behaving independently.

   The real reason high humidity is associated with convection is that rising, cooling air will eventually lead to saturation and condensation. The more humid the air, the earlier this will occur. Once condenstation is happening, the release of the latent heat of vaporization reduces the cooling rate. This increases the instability of the air - promoting greater convection.

   This is all basic, introductory meteorology.

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4. BilB at 07:00 AM on 5 September, 2017

   Thanks for your feedback Swayseeker. I've put this argument up several times hoping for some quantitative comment. When I did the calculation it was difficult for me to get the parts of the calculation in the same form and I came up with a a different answer. I'll go over it again to see where I went wrong.

   I still maintain that the premise that the density difference of moist air is the primary driver of climate change holds up, though the energy content of the moisture turbo charges air flows once condensation conditions are reached. 

   Evidence regarding clouds is based on the experience of aircraft descending to and through clouds. Air smooth until once in the cloud where turbulence is significant then into smooth air below. The energy flows within clouds have to be really interesting.

   Bob Loblaw

   Well mixed gasses? granted. But gasses do not mix instantaneously, it takes time and density gradients must be present near a low density gas emitting sources. Evidence? A fart (lower density methane) does not reach every one in a crowd immediately once emitted, it takes time, even in a crowded elevator. In fact methane releases in the Arctic appear to be forming plumes which carry the gas to altitude rather than mixing uniformally at the surface (still subject to scientific validation). 

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5. Bob Loblaw at 07:43 AM on 5 September, 2017

   Yes, BillB, a fart in an elevator takes a bit of time to spread around an elevator. Try the same experiment outside. Add a bit of wind. We're talking minutes, not hours, for the gases to mix. The atmosphere is a turbulent place. Horizontal pressure and density differences are rapidly equalized over short distances (m to km - feet to miles, if you prefer).

   Show me a reference for your Arctic plumes of methane claim. I doubt it shows what you think it shows.

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6. BilB at 09:51 AM on 5 September, 2017

   Bob Loblaw

   This is the source site http://arctic-news.blogspot.com.au/2014/01/high-methane-levels-over-the-arctic-ocean-on-january-14-2014.html
   ...but the suggestion was made regarding methane growth in the tropics which may be exacerbated by methane coming more directly from the Arctic. I'm still looking for the reference.

   Some say Sam Caranae are alarmist, but I prefer to see Arctic News as attempting to examine evidence in real time rather than "studied and published" time with the aim of directing exhaustive study where it will better quantify dangerous trends. And here is the particular item

   http://arctic-news.blogspot.com.au/2017/03/methane-erupting-from-arctic-ocean-seafloor.html

   ...again requiring scientific validation.

   Yes, air movement over the oceans generally promotes mixing of water vapour into the broader atmosphere reasonably quickly, but air movements are not always rapid and they are generally the product of a low air pressure system which is itself the product of rising air for which the question becomes what is driving that process.

   For another way of looking at this is to see if thermal energy in dry air alone can create the same degree of atmospheric change as humid air can. From what I can see desert wind speeds can reach 180 kph but nothing like those possible in hurricanes, and desert air convection can form tornadoes and dust storms, but not cyclonic structures.

   Clearly H2O vapour makes a huge difference to the intensity of atmospheric air movements, so the question I am posing is, is it the mixed humid air density difference that makes the difference, or is it purely warm air convection, and/or the energy that the moisture carries and transfers to the air once condensation occurs (at altitude) that makes low pressure systems so intense. From what I am reading purely thermal lows have weak circulation.

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   Moderator Response:

   [PS] Fixed links. Please learn how to do this yourself with the Link button in the comment editor.

7. Bob Loblaw at 11:12 AM on 5 September, 2017

   BillB:

   There is nothing in your link to suggest that any "plumes" of methane have formed through a process of methane being lighter than other gases. The mechanisms of what meteorologists call "lift" are well understood, and local lift (convection) is explained entirely by standard meteorology. Any local updraft will carry the methane along with it.

   The role of water vapor enhancing convection is also well understood, through the release of latent heat as water vapour condenses in the rising/cooling air.

   Your discussion shows a tremendous lack of knowledge of standard meteorology. You are trying to explain things that are already well-explained, and your explanations do not make sense.

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8. BilB at 12:28 PM on 5 September, 2017

   BobL

   I'm not sure which part of the article that you read. The particular comment is under the heading "The signature of seafloor methane" where the author is speculating that the rate of increase of methane in the stratosphere "looks like" being the product of plumes delivering sea floor methane very directly to high altitudes. I believe this to be highly probable and await more direct evidence. I believe this just as I have projected for many years that Atlantic Conveyor heat would eventually penetrate deep into the Arctic to soften sea floor clathrates and release large amounts of methane to the atmosphere, which is looking more probable every year.

   It seems we will have to agree to disagree on my postulation on air density.

   Of course these things are known and occur routinely in nature, just as does CO2 capture and re-emission of infra red radiation, both to a very marginal degree.

   My point is that one very marginal influence, CO2, provides the small degree of change over the entire Earth surface to provide a marginal amount of additional material, H2O, to the entire near surface atmosphere to produce a profound change via a very merginal density difference to the climate impact on humans. It is about perception and identifying the pivotal driver of each process of change. CO2 is heating the oceans ever so slightly, moist air density difference is accelerating atmospheric circulation, I believe, and that is the Global Warming/Climate Change couplet that periodically reshapes our planet.

   If you want to demolish my argument demonstrate quantitatively that the density difference of humid air provides zero "lift" to an air mass relative to a dry air mass at the same temperature.

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9. nigelj at 16:51 PM on 5 September, 2017

   BilB,

   "My conclusion is that rain clouds are formed not by thermal up lift but by humidity uplift."

   Why would you think that thermal effects on air density would be less than humidity effects on air density? Where are your calculations?

   Remember temperature swings can be quite large so have a significant effect on density. And as Bob says humid air dissipates so has an insignificant effect. 

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10. nigelj at 17:37 PM on 5 September, 2017

    BilB

    "Of course these things are known and occur routinely in nature, just as does CO2 capture and re-emission of infra red radiation, both to a very marginal degree."

    Its not marginal. Wheres your evidence its marginal? CO2 molecule is recognised as having a very significant effect on radiation 

    en.wikipedia.org/wiki/Greenhouse_gas#Greenhouse_gases

    Too much unqualified, bold, fact free blather on this website.

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11. nigelj at 17:42 PM on 5 September, 2017

    I'm talking about fact free blather from people like BilB. Just to be clear.

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12. BilB at 18:07 PM on 5 September, 2017

    Hi Nigelj, Where Bob says that "humid air dissipates" all that can mean is that humidity in an air mass can change, and as humidity changes the air mass density changes. 

    As to the rest of your comment, I am thinking about it and testing my notion in the Southern Ocean with earth.nullschool.

    Swayseeker dampened my argument challenging my earlier calculation and I have to re-examine my earlier work.

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13. MA Rodger at 22:32 PM on 5 September, 2017

    BilB @12,
    A thought for you while you "re-examine (your) earlier work."
    The comment by Swayseeker @2 is correct but rather exaggerates the effect you are describing. It is indeed correct that at 40ºC, wet air has the same drop in density from dry air as achieved by an increase in temperature of dry air to 45ºC. By your "back of the envelope calculations it takes a 20 degree C difference in dry air to equal that humid air uplift capacity" and this would also be correct for dry air at 52ºC. Of course such temperatures of 52ºC or even 40ºC are pretty rare within the Earth's climate, even at ground level.
    But if you are talking about climate change, such calculated effects do exaggerate the change you discribe. The value under consideration should be the relative influence of humidity in reducing density as temperature rises. A warmer climate will of course have less dense air, wet or dry. But at 20ºC (a more common climatic temperature), the drop in density will be at least 85% due to the temperature rise and less than 15% due to the potential for higher specific humidities. It is only at temperatures above 70ºC that the drop in density can be dominated by humidity.
    And be sure, the drop in density due to rising specific humidity is a factor in climate modelling but it is not a major factor.

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14. BilB at 23:06 PM on 5 September, 2017

    Thanks for that comment MA Rodger. My "earlier work" was very rudimentary as I said at the beginning. I will now do as comprehensive an iterative model as I can achieve with a spreadsheet to satisfy myself what is and isn't in the water cycling process. I'm happy to be wrong if I am but I want to fully understand the dynamics with this. I can see that there is a complicated relationship between air moisture temperature pressure and the relative environment all of which I will only fully appreciate with some extensive experimentation with a model, and that is going to take me some time.  

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15. nigelj at 07:00 AM on 6 September, 2017

    BilB

    I dont think you can simply ignore  the mixing of gases effect. You would have to quantify it properly. Its probably more significant than you think.

    I'm not a scientist but I know enough that you have to be careful before you disnmiss the conventional wisdom. Obviously rising air is a combination of  both temperature and humidity altering density but my guess is its mostly temperature and MA Rodger clearly knows what hes talking about and demonstrates this.

    But to come back to your original point its still increased global temperatures behind both phenomena. I wasnt sure what you were really getting at in respect of your talk about the climate sceptics.

    But good luck its interesting exploring these things.

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16. Bob Loblaw at 10:43 AM on 6 September, 2017

    My apologies, BillB - I only read your first link. I see the second has more discussion, including the mention of plumes. Primarily, though, it discusses plumes originating on the sea floor. These would rise through the water until reaching the surface.

    I see no evidence in either post that the atmospheric transport of methane to higher altitudes is the result of methane itself rising as an independent plume through the atmosphere. I don't think it is possible to demonstrate that with the level of detail in the data provided. As such, it remains an hypothesis, not a fact.

    As for water vapour causing density changes that lead to convective lift, I repeat again that this is contrary to standard meteorology. I will note a few things:

    1. Water vapour is tyically released over a wide area, not at a localized point. It is driven by evaporation, which is driven by energy availability (primarily sunlight).
    2. When there are variations in surface wetness, the wet areas will evaporate more. They will also be cooler, as the energy required to evaporate water is not available to heat the surface. Try walking from wet grass onto pavement in bare feet, on a hot/sunny summer afternoon. The difference can be tens of degrees.
    3. As the dry areas are hotter, the air above them is less dense. Thus hot air rises and it is the dry areas that see the greater upward movement of air.
    4. Two regional circulation patterns that are driven by this difference are land-sea breezes and monsoons. In both cases the warm, dier rising air over land is replaced by coller, wetter air moving off the water. Air is subsiding over the water.

    Thus, observations are contrary to your hypothesis.

    As for me doing the calculations for you, no thanks. The calculations are done every day in every weather model, and it is the thermal effects that dominate the motion, not the humidity.

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17. Bob Loblaw at 10:46 AM on 6 September, 2017

    Point 4 should say "warm, drier air".

    One more example: the visual atmospheric shimmering over a road on a hot summer day, The air is rising over the road - the driest, hottest area of air.

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18. Bob Loblaw at 10:51 AM on 6 September, 2017

    One last point (for now):

    Going back to the wet lawn vs. dry pavement, take a bit of time to think whether that huge difference in surface temperature can be felt as a difference in air temperature at a height of a metre or two over the two surfaces.

    Then think about what that means for how quickly the atmosphere mixes the air between the two sources of heat/water vapour.

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19. michael sweet at 03:43 AM on 8 September, 2017

    This Guardian op-ed discusses attribution of global warming problems (like sea level rise) to individual companies and whether those companies should have to pay for the proportion of the damage they cause.

    For example, they say ExxonMobile, Chevron and BP  by themselves are responsible for 6% of sea level rise because of their CO2 emissions.  During Sandy in New York City alone, over $2 billion dollars of damage was caused by higher sea level.  Should these companies have to pay for the damage they are known to have caused?

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20. Tom13 at 00:50 AM on 9 September, 2017

    #19 Michael Sweet -

    During Sandy in New York City alone, over $2 billion dollars of damage was caused by higher sea level.

    Sandy came ashore in the funnel of NY , at high tide, at the high lunar tide.  Those three factors drawfted any affect of the the additional 12-13inches of higher sea level since circa 1850.  The difference in high & low tide in NYC is approx 6 ft,.  Add in the high tide and high lunar tide factors, and the difference is approx 7 feet.  This  means the 12 inches is a minute difference.

    www.weatherforyou.com/reports/index.php?forecast=tides&place=New+York&state=NY

    Assuming the 6% attribution to XOM Chevron, and BP is correct, - that equates to less than one inch - How much additional damage would be a reasonable estimate for the 1 inch vs the 6+ feet for the tide.

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21. michael sweet at 02:44 AM on 9 September, 2017

    Tom13

    I have provided a link to a peer reviewed study (the authors of the OP-Ed I cited link to their peer reviewed study) that found that the last foot of sea level rise caused $2 billion in damage.  You respond with "I doubt it" and a seat of the pants obbservation.  You generally do not cite anything to support your wild speculations.  Are you claiming that the scientists who did the peer reviewed study do not konw the tidal range of New York?  Your argument is absurd.

    This is a scientific blog.  If you cannot cite peer reviewed data to support your claims you should go somewhere else.  "I doubt it" is not an argument.

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22. michael sweet at 02:58 AM on 9 September, 2017

    Tom13

    For those who cannot do math, 6% of $2 billion is $120 million.  That is for New York only and only for Sandy.  When worldwide damage for all storms, drought and floods is calculated it will be much, much greater.

    I am currently on the Chesapeake bay in Maryland.  The houses nearby where I am have lost 50% of their value because of sea level rise.  Will land in Miami be worth anything after Irma?  This is the cost of Global Warming.

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23. Tom13 at 03:52 AM on 9 September, 2017

    Michael # 22

     I am currently on the Chesapeake bay in Maryland. The houses nearby where I am have lost 50% of their value because of sea level rise.

    Do you have a peer reviewed study supporting your calculation of lost value to SLR.  Chesapeake bay area has a lot of subsistance Have you factored that into your estimate?

    Michael # 21 _ I gave you link to the tide gauges.  The fact that Sandy hit into the funnel of  new york harbor, hudson river, etc is well know and the geography is well known,  Would not think you need a citation for that info.  That Sandy came in at both the high tide and at the high lunar tide is also well known, I would not think you need a citation for that data.  I did provide a link to the tide gauges which should assist you in reviewing the reasonableness of the peer reviewed study and the reasonableness of the computation.

    Can you provide a link to the Actual Study.  You provided a citation to the guardian, not exactly a scientific journal. The links the guardian links to either advocacy websites or dead ends.   A link to the actual study does make it easier to review the reasonableness to the study.

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24. Tom13 at 04:12 AM on 9 September, 2017

    Michael - You mention the gaurdian article as being peer reviewed.  How do you get a peer reviewed study on an issue where the factors are highly subjective? 

    I have provided a link to a peer reviewed study (the authors of the OP-Ed I cited link to their peer reviewed study) that found that the last foot of sea level rise caused $2 billion in damage.

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25. John Hartz at 04:45 AM on 9 September, 2017

    Speaking of Sandy and sea level rise...

    For example, even if we could say nothing else, we can conclude that sea level rise has contributed to the coastal flooding associated with recent major hurricanes: nearly a foot at Battery Park in New York City in the case of 2012 Superstorm Sandy and roughly half a foot in the case of Hurricane Harvey. The seemingly modest 1 foot of sea level rise off the New York City and New Jersey coast made a Sandy-like storm surge of 14 feet far more likely, and led to 25 additional square miles of flooding and several billion extra dollars of damage.

    What We Know about the Climate Change–Hurricane Connection by Michael E. Mann, Thomas C. Peterson & Susan Joy Hassol, Scientific American, Sep 8, 2017

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26. Tom13 at 05:19 AM on 9 September, 2017

    Thank to the link to an actual study.  - A brief review of the study raises the following observations - Hope you can address

    1) the study appears to attribute all the SLR rise to warming without separating the natural SLR from the agw slr. There has been approx 1.0-1.5mm rise per year since the emergance from the LIA and even before,

    2) the attribution to various other factors appears to be underweighted.  The other factors being the funnel effect of the geography with Sandy hitting at the very center point of the funnel, , the lunar tide and the high tide.  All three of those factors contributed significantly to the storm surge.  The study doesnt provide the actual math ( at least not in easily obtainable format) which makes it difficult to ascertain the reasonableness of the assumptions

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27. Tom13 at 06:39 AM on 9 September, 2017

    The seemingly modest 1 foot of sea level rise off the New York City and New Jersey coast made a Sandy-like storm surge of 14 feet far more likely,

    Two additional points -

    A) the 1 foot SLR since circa 1850 would only be partly attributable to AGW.  As the the graph from the study note, there has been a reasonably steady rate of SLR since circa 800ad.  A reasonable estimate of the SLR since circa 1850 would be less than 1/2 foot.  Obvioulsy cant attribute the full 1ft to AGW.

    B) Since the storm surge is the difference between the water level without the storm and the level with the storm, the delta for the storm surge shouldnt change. In other words the height of the storm surge should be affected. 

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28. John Hartz at 07:00 AM on 9 September, 2017

    Michael Sweet & Tom 13:  Please take your ongoing discussion of the link between sea level rise and Sandy's storm surge to the SkS rebuttal article:

    The connection between Hurricane Sandy and global warming by Dana Nuccitelli.

    It is chocked full of references/links to peer-reviewed studies.

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