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New studies confirm weakening of the Gulf Stream circulation (AMOC)

Filed under: — stefan @ 17 September 2020

Many of the earlier predictions of climate research have now become reality. The world is getting warmer, sea levels are rising faster and faster, and more frequent heat waves, extreme rainfall, devastating wildfires and more severe tropical storms are affecting many millions of people. Now there is growing evidence that another climate forecast is already coming true: the Gulf Stream system in the Atlantic is apparently weakening, with consequences for Europe too.

The gigantic overturning circulation of the Atlantic water (dubbed AMOC) moves almost 20 million cubic meters of water per second – almost a hundred times the Amazon flow. Warm surface water flows to the north and returns to the south as a cold deep current. This means an enormous heat transport – more than a million gigawatts, almost one hundred times the energy consumption of mankind. This heat is released into the air in the northern Atlantic and has a lasting effect on our climate.

But since the 1980s, climate researchers have been warning of a weakening or even a cessation of this flow as a result of global warming. In 1987, the famous US oceanographer Wally Broecker titled an article in the scientific journal Nature “Unpleasant surprises in the greenhouse”. Even Hollywood took up the subject in 2004 in the film “The Day After Tomorrow” by the German director Roland Emmerich. However, there were no measurement data that could prove an ongoing slowdown.

Only since 2004 has there been continuous monitoring at 26°N in the Atlantic (RAPID project). Although the data show a weakening of the current system, the measurement series is still too short to distinguish a possible climate trend from decadal variability. For the longer-term development of the Gulf Stream system, we must therefore rely on indirect evidence.

A long-term AMOC weakening should lead to a cooling in the northern Atlantic. Such a regional cooling in the middle of global warming has been predicted by climate models for a long time. And indeed, the evaluation of data on sea surface temperatures shows that the northern Atlantic is the only region of the world that has escaped global warming and has even cooled down since the 19th century (see graph). In addition, one can see a particularly strong warming off the North American coast, which according to model simulations is part of the characteristic “fingerprint” of a weakening of the Gulf Stream circulation.

Diagram of the Gulf Stream system with the warm surface current and the cold deep current. The actual Gulf Stream off the US coast is a part of this more comprehensive circulation system. The color shading shows the measured temperature trend since the late 19th century. This diagram is based on Caesar et al., Nature 2018 and first appeared in the Washington Post.

This fingerprint is regarded as important evidence, and not least because of this, the Intergovernmental Panel on Climate Change (IPCC) stated for the first time a year ago in the Summary for Policy Makers of its Special Report on the Oceans:

 “Observations, both in situ (2004–2017) and based on sea surface temperature reconstructions, indicate that the Atlantic Meridional Overturning Circulation (AMOC) has weakened relative to 1850–1900.”

New studies support long-term weakening

Two new studies now provide further independent evidence of this weakening. In August a paper by Christopher Piecuch of the Woods Hole Oceanographic Institution on the Florida Current – the part of the Gulf Stream system along the Florida coast – was published. Although continuous measurements of the current have only been available since 1982, Piecuch was able to reconstruct the strength of the Florida Current over the last 110 years from measurements of the sea level difference between the two sides of the current. To do so, he used 46 tide gauge stations in Florida and the Caribbean as well as a simple physical principle: the Coriolis force deflects currents in the northern hemisphere to the right, so that the water on the right side of a current stands higher than on the left. The stronger the current, the greater the difference in sea level. Comparison with measurements since 1982 shows that the method works reliably.

The result: the Florida current has weakened significantly since 1909 and in the last twenty years has probably been as weak as never before. Piecuch’s calculations also show that the resulting reduction of heat transport is sufficient to explain the ‘cold blob’ in the northern Atlantic.

This Monday, in Nature Climate Change a further study appeared, of researchers of Peking University and Ohio State University (Chenyu Zhu and Zhengyu Liu). For the first time, their paper provides evidence for an AMOC slowdown based on data from outside the North Atlantic. Model simulations show that a weakening of the AMOC leads to an accumulation of salt in the subtropical South Atlantic. This is due to the fact that strong evaporation in this region constantly increases the salinity, while the upper branch of the ocean circulation drains the salty water northwards, continually bringing in less salty water from the south. When this current weakens, the water in this region becomes saltier. This is exactly what the measured data show, in accordance with computer simulations. The authors speak of a “salinity fingerprint” of the weakening Atlantic circulation.

Video animation of ocean currents in the CM2.6 climate model of the Geophysical Fluid Dynamics Lab in Princeton:

In addition to these oceanographic measurements, a number of studies with sediment data indicate that the Gulf Stream circulation is now weaker than it has been for at least a millennium.

These current changes also affect Europe, because the ‘cold blob’ out in the Atlantic also influences the weather. It sounds paradoxical when you think of the shock frost scenario of the Hollywood blockbuster The Day After Tomorrow: but British researchers found that in summer the jet stream in the atmosphere likes to take a route around the south side of the cold blob – this then brings warm winds from the southwest into Europe, leading to heat waves there, as in the summer of 2015. Another study found a decrease in summer precipitation in northern Europe and stronger winter storms. What exactly the further consequences will be is the subject of current research.

However, the latest generation (CMIP6) of climate models shows one thing: if we continue to heat up our planet, the AMOC will weaken further – by 34 to 45% by 2100. This could bring us dangerously close to the tipping point at which the flow becomes unstable.

This article appeared originally in German in Der Spiegel: Das Golfstromsystem macht schlapp

269 Responses to “New studies confirm weakening of the Gulf Stream circulation (AMOC)”

  1. 151
    Susan Anderson says:

    nigelj @~135
    Thanks for the extended discussion about forest fires and compliments to the excellent Daniel Bailey.

  2. 152
    David B. Benson says:

    Barton Paul Levenson @147 — Please reference the easiest undergraduate text so that I can pass along the recommendation as occasion arises elsewhere. Thank you in advance.

  3. 153
    jb says:

    Mack at, well, lots of places:

    Unfortunately, we have to play whack-a-troll with this guy. If he claims that the math is wrong on the calculation of the earth’s no atmosphere temperature, the burden should be on him to show that the VERY simple calculation is wrong.

    The idea is that the energy coming in from the sun equals the energy leaving from the earth, so the equation must look like:

    (solar constant)*(1-albedo)*(pi*earth’s radius^2) = (stefan boltzmann constant)*(earth’s temperature^4)*(4*pi*earth’s radius^2)

    If you solve this for earth’s temperature, you get about 255 kelvin, which is -18 degrees celsius. For Mack to show that this solution is incorrect, he has to show that at least one of these numbers is wrong. Which one? If he can’t answer this, he shouldn’t be permitted to take up white space on this blog.

  4. 154

    M 148: I just get… “infrared radiation”….. no math…. even though you said you’d give me “the math” @38.

    BPL: Okay, I’ll give you the math.

    The surface of the Earth is at 288 K on average, so assuming blackbody emissivity, it radiates 390 watts per square meter by the Stefan-Boltzmann law:

    F = ε σ T^4

    where ε is the emissivity (1 for a blackbody), σ is the Stefan-Boltzmann constant (5.670373 x 10^-8 W m^-2 K^-4 in the SI), and T is the temperature in kelvins.

    The Earth gets 184 W m^-2 in insolation of which it absorbs 161 W m^-2 (i.e., it has a surface reflectivity averaging about 0.125). That means it must be getting 390 – 161 or 229 W m^-2 from some other source.

    And yet we know the Earth constantly loses 80 W m^-2 by evapotranspiration and 17 W m^-2 by pure convection, so it must actually be gaining 229 + 97 = 326 W m^-2 from this other source.

    This other source is, of course, the atmosphere. Using the Stefan-Boltzmann law again, we can calculate that the atmosphere is at an equivalent temperature, as seen from the surface, of 275 K.

    Does that help?

  5. 155

    DBB 152,

    For a really easy one, George S. Philander’s “Is the Temperature Rising?” (1998) is a good one. For more math, John Houghton’s “The Physics of Atmospheres” (3rd ed. 2002) is very thorough without being impossible. Grant W. Petty’s “An Introduction to Atmospheric Radiation” (2nd ed. 2006) is also very good. On the hard side would be Goody and Yung’s “Atmospheric Radiation” (1989).

  6. 156
    Johann G. K. Gizurarson says:

    Hi guys,

    If the AMOC is weakening (which I’m quite compelled to believe given various well presented data throughout couple of years), why isn’t the climate here in Iceland cooling down? E.g. summer of 2019,2016,2012,2011,2010,2008,2007,2003 were all extremely warm on any timescale here in the city of Reykjavik.
    According to IPCC even if it [AMOC] weakens there will still be warming over land. However, Reykjavik is at the coast (one of the nearest “big” places to the famous cold blob) and there has no cooling happened. If we compared all months all years from 2000 to 2020 almost every month has been warmer in Reykjavik than the 1961-1990 average. When are we going to see cooling here? Or are we only going to see reduced warming compared with if the AMOC wasn’t changing?

    With regards,

    Jóhann (Stefan & co; thanks for great work!)

  7. 157

    #149, Mack–

    I’m thinking of writing a REAL science book myself…

    Yeah, keep us updated. I want to make sure I have a good supply of popcorn when it comes out.

    If it comes out!

  8. 158
    MA Rodger says:

    I see Maniac Mack @148 is again trying to re-write this comment thread to suit his personal fantasies. Perhaps I should set him straight.

    Mack @148,
    You are wrong.
    Nobody said @38 they were going to give you “the math”. You were simply asked if you wanted “the math”. Your response @47, you will recall, was to say:-

    I know the math. Maybe you and all the experts have made a mistake in “the math” Reality doesn’t always agree with “the math”.

    Subsequently, when @57 it was suggested that your comments showed you “don’t actually understand the math,” your response @63 was:-

    I do understand the math and I do know the mistake in the math. You are obviously still ignorant of the mistake in the math. A mistake so bad we have supposedly intelligent people like yourself trying to tell me that the ATMOSPHERE is keeping the oceans in liquid state.

    Yet, when asked to set out this “math” you understand, complete with the “mistake so bad”, you are unable to oblige.

    It was only after all this nonsense from you up-thread that @120 that you finally agreed that you do “want the math” saying:-

    “Well, yes, I think I’m prepared for you to hit me with the math. Go ahead, make my day.”

    And to be pedantic, you had only been asked if you “want the math” which isn’t entirely the same as somebody saying they would “give” you this “math”.

    True, you do complain @136 that other “math” provided is not the same as the ‘ocean-melting’ “math” you admitted @120 you were “prepared for” receiving. But I would suggest that you probably are not “prepared,” as you give all the signals of somebody with zero understanding of “math” (a view also expressed by Barton Paul Levenson @57, and reinforced by you successfully demonstrating elsewhere @RealClimate your total ignorance of the Laws of Thermodynamics).
    Of course, I am always happy to amend my views to suit available evidence. So do feel free to consider responding to my comment @76 which anybody with the slightest ability in mathematics would not have found unreasonable. You may recall it ended:-

    “So a gentle nudge, chum. Set out this alleged mathematical mistake you are bleating on about, or shut you cake hole!!”

  9. 159
    William B Jackson says:

    #158 I make no claim to great knowledge of math but I find Mack positively Trumpian in his denial of objective reality. Luckily while Trump’s denial leads to unnecessary deaths Mack’s leads only to time wasting nonsense posts.

  10. 160
    Mack says:

    @158 MA Rodger

    @154 BPL
    Thanks for the math, BPL,
    The first mistake you’ve made is the Earth with an emissivity of 1…sorry,the entire surface of the Earth is not covered in black asphalt. The Earth’s total emissivity has been measured at 0.82…we are a blue planet.
    The second mistake you’ve made is the 161 watts/sq.m insolation at the Earth’s surface. You are following Trenberth’s looney Earth Energy Budget diagrams showing only 161 w/sq.m absorbed at the Earth’s surface…. totally insufficient. That’s the big mistake. Reality is .. it’s about that 340 watts/sq.m you thought was at the Top of the Atmosphere (TOA). You’re confused between the surface of the Earth and the “surface of the Earth” as designated by Trenberth to be at the TOA.
    So, if you slot those numbers into the Stefan-Boltzmann equation, BPL…. ie emissivity = 0.82 , area = 1 sq.m , Radiative energy = 340 watts/sq.m… you’ll arrive at about 292K or 19deg C. at Earth’s surface.
    The 340 watts/sq.m. you knew, of course, comes from taking the TSI, which exists at the TOA, of 1360 watts/sq.m and then geometrically “attenuating” it down, first by halving for day/night, the 1/2 again for the lit side Earth curvature….divide by 4.
    The 292K or 19deg C, is still a bit higher than the GAT, measured at about 15deg.C …so the further reduction is accounted for by atmospheric attenuation… gases ,vapour, aerosols, clouds etc … which you can figure out from the S-B equation to be about 20watts/sq.m.
    Geometric “attenuation” plus atmospheric attenuation on the real,measured 1360 watts /aq.m that exists at the TOA, using the Stephan-Boltzmann equation, provides us with the real global average temperature, without the need for any atmospheric “greenhouse effect.”
    Anything else you need to know, BPL?

  11. 161
    MA Rodger says:

    I see that Maniac Mack has set out two alleged mistakes. (Perhaps they collectively constitute the AGW-science-confounding “mistake so bad” he has mentioned upthread.) While for the “second mistake”, he sets out is an embarrassingly stupid account, the “first mistake” involves a less widely-discussed value, the emissivity of the Earth’s surface.

    Maniac Mack tells us “The Earth’s total emissivity has been measured at 0.82…we are a blue planet.” This likely does no more than repeat the denialist blather of Jennifer Marohasy who also says in a 2011 blogpost “The emissivity of the surface has been measured, not assumed, and it is 0.82.”
    This particular blogpost never manages to say who did this ‘measuring’ but a second 2011 blogpost from the same author goes into the subject a little differently and names two references for the statement “The surface has a measured emissivity of 0.82; it means that the surface emits 82% of the energy it absorbs.”
    Ignoring the obvious misunderstanding of the physics, the references to measured emissivity are to the URL of an obsolete webpage and Modest (2003) ‘Radiative heat transfer’, the latter hardily the go-to reference for a measured emissivity value for the Earth’s surface. And if it did set out this 0.82 value, it is unlikely to be more than a point measurement as measurements of ocean & land surface seldom find such values outside desert regions.

    Of course, Maniac Mack may be thinking of some other source for his measured emissivity of Earth’s surface. So the question remains – Is there another source to back his bold assertion on emissivity that actually exists outside his warped imagination?

  12. 162

    M 160,

    Well, you’ve responded with your own “math.” There are so many mistakes, it’s hard to know where to start. I’ll try to tackle them in order.

    M: The first mistake you’ve made is the Earth with an emissivity of 1…sorry,the entire surface of the Earth is not covered in black asphalt. The Earth’s total emissivity has been measured at 0.82…we are a blue planet.

    BPL: I was talking about emissivity at the surface, which has been measured with instruments. Various estimates range from about 0.9 to 1.0, with most clustered near the upper end. Roeckner et al. (1993) get 0.996, for instance.

    M: The second mistake you’ve made is the 161 watts/sq.m insolation at the Earth’s surface. You are following Trenberth’s looney Earth Energy Budget diagrams showing only 161 w/sq.m absorbed at the Earth’s surface…. totally insufficient. That’s the big mistake. Reality is .. it’s about that 340 watts/sq.m you thought was at the Top of the Atmosphere (TOA). You’re confused between the surface of the Earth and the “surface of the Earth” as designated by Trenberth to be at the TOA.

    BPL: No, of that 340 W m^-2 at top of atmosphere, about 25% is reflected away by clouds and Rayleigh scattering before it ever gets to the surface. Actual insolation is 184 W m^-2, and 23 W m^-2 of that is reflected by the surface, mostly by ice near the poles but also by land and, to a tiny extent, water.

    M: So, if you slot those numbers into the Stefan-Boltzmann equation, BPL…. ie emissivity = 0.82 , area = 1 sq.m , Radiative energy = 340 watts/sq.m… you’ll arrive at about 292K or 19deg C. at Earth’s surface.

    BPL: Right, but those numbers are wrong, so the fact that you get something roughly like the right answer, though not identical to it, is a coincidence. You’ve merely taken a too-low emissivity and compensated for it with a too-high insolation.

    M: The 340 watts/sq.m. you knew, of course, comes from taking the TSI, which exists at the TOA, of 1360 watts/sq.m and then geometrically “attenuating” it down, first by halving for day/night, the 1/2 again for the lit side Earth curvature….divide by 4.

    BPL: Right. Well done.

    M: The 292K or 19deg C, is still a bit higher than the GAT, measured at about 15deg.C …so the further reduction is accounted for by atmospheric attenuation… gases ,vapour, aerosols, clouds etc … which you can figure out from the S-B equation to be about 20watts/sq.m.

    BPL: You’re forgetting reflection and scattering.

    GM: Geometric “attenuation” plus atmospheric attenuation on the real,measured 1360 watts /aq.m that exists at the TOA, using the Stephan-Boltzmann equation, provides us with the real global average temperature, without the need for any atmospheric “greenhouse effect.”

    BPL: You can’t use the 1360 W m^-2 because the Earth receives solar energy on its cross-section, which is a disk, but has a total surface area four times greater, because it’s (roughly) a sphere.

  13. 163

    #160, Mack–

    A ‘lovely theory slain by ugly fact.’

    The energy at Earth’s surface is pretty well-constrained with good old empirical measurement using (inter alia) such as these:

    https://www.campbellsci.com/blog/pyranometers-need-to-know

    As one random analysis in the literature (Wild et al., 2012) puts it:

    …we make extensive use of the growing number of surface observations to constrain the global energy balance not only from space, but also from the surface.

    https://link.springer.com/article/10.1007/s00382-012-1569-8

    And their bottom line?

    Our analyses favor global mean downward surface solar and thermal radiation values near 185 and 342 Wm−2, respectively, which are most compatible with surface observations. Combined with an estimated surface absorbed solar radiation and thermal emission of 161 and 397 Wm−2 respectively…

    It’s not likely that an entire set of scientific disciplines would “confuse” shortwave and longwave radiation. Random blog commenters, well, that’s another story.

  14. 164
    Astringent says:

    Mack at #160 And the first mistake that dear Mack has made is thinking that term ‘blackbody radiation’ is something to do with an object’s colour. It’s not! It’s dependent on temperature. While ε for the earth isn’t exactly 1 it’s close enough to be nearly immaterial in the calculations. like to critique the rest of his ramblings, but they aren’t coherent enough to be critiqued.

  15. 165
    Victor says:

    BPL: “The amount of heat involved in a one degree increase is therefore about 5.179 x 10^21 joules. This is an amount of energy equivalent to 13.68 trillion Hiroshima bombs.”

    V: Well that explains the explosion I heard this morning. Or was it the garbage truck going by?

    Kevin McKinney: Victor, thank you for confirming in tediously irrelevant detail what I said in my #109: land areas are warming at roughly twice the rate of the world as a whole. (I.e., land plus ocean.) Can I now assume you understand that piece?

    V: As I recall, the standard “scientific” response to the notorious “hiatus” involved all that missing heat diving down from the atmosphere into the ocean. That was a period of roughly 16 years when land temps. were relatively flat, but (according to the “experts”) the ocean was heating up drastically.

    K: In reference to the sneer about Arctic ‘databases’, I find it hard to believe that you don’t know full well that every analysis of global temperature save Hadcrut includes the Arctic. So I’m assuming the comment wasn’t actually moronic, but merely disingenuous in the extreme.

    V: No, you are the one who’s being both disingenuous AND moronic. I was not referring to official “scientific” databases, as should have been obvious. I was (sarcastically) wondering how an inanimate object such as “the Arctic” is able to determine whether temperatures have been rising over the past several years without maintaining a database in which yearly temps. are duly recorded. Obviously “the Arctic” is incapable of maintaining such a database, thus has no way of determining relative warmth from year to year. Thus your claim that what really counts is changing temperatures over time rather than immediate atmospheric conditions is not only spurious but silly.

    K: Victor asked:

    Thus, according to “the science,” we would expect to find more extreme weather-related events in the lower latitudes as we review Earth’s history. So permit me to repeat my earlier question: is that the case?

    Let me repeat my answer:

    No.

    But maybe a longer answer would help.

    V: Actually your longer answer is no help at all as it’s obvious you don’t know what you’re talking about.

    K: First, what is meant by “extreme weather events?”

    Since “weather” refers to specific conditions at a particular place and time, it’s evident that we must here be considering events as defined with reference to local norms.

    V: That’s precisely my point. If temperature were driving extreme weather then norms associated with particular localities would have reflected that. And since a 1 degree (or 2 degree) difference in temperature can, according to you, mean the difference between tolerable conditions and intolerable conditions then populations would be fleeing from the warmer regions to the cooler ones. We’d be seeing a mass migration from, say, Florida to Canada. Seems to me the migration has tended to go in the opposition direction. Do you wonder why?

    K: So, presumably, 5mm of precipitation would be considered “extreme” were it falling on Santa’s workshop, whereas on Aruba it might be completely unremarkable.

    So, bottom line here: both Aruba and Santa’s workshop experience “extreme” precipitation at one time or another, but the amounts for the former are going to be much larger than for the latter.

    V: Sorry Kevin, but I presumed we were talking about an “existential” threat to life on this planet, not relative differences in normal precip. from one region to the next.

    K: The foremost example would be tropical cyclones (AKA hurricanes). As explained in Brittanica, tropical cyclones have specific physical characteristics which are dependent upon the tropical marine environment. It’s possible for tropical cyclones to persist as entities after exiting the tropics, but they lose those specifically tropical characteristics (most obviously, the famous “eye”) and become more diffuse “extra-tropical cyclones.”

    Obviously, this is one example of an “extreme weather event” which, indeed, is found “more… in the lower latitudes,” to use Victor’s words.

    V: Yes indeed. And on this we can agree.

    K: However, the context of this whole discussion was drying/evaporation/wildfire, not hurricanes.

    V: Exactly.

    K: In that context, the extremes would be expected, just as I said, where the *change* is greatest–i.e., the Arctic. A salient example there would be wildfire on the tundra, as mentioned above.

    V: So what you are saying is that “the Arctic” made a mental note of the fact that the climate has changed over the years and thus decided to set itself on fire as a response. (Sarcasm, in case you fail to notice.)

  16. 166
    nigelj says:

    Victor @165

    “That’s precisely my point(talking to KM). If temperature were driving extreme weather then norms associated with particular localities would have reflected that. And since a 1 degree (or 2 degree) difference in temperature can, according to you, mean the difference between tolerable conditions and intolerable conditions then populations would be fleeing from the warmer regions to the cooler ones. We’d be seeing a mass migration from, say, Florida to Canada. Seems to me the migration has tended to go in the opposition direction. Do you wonder why?”

    I can’t recall KM ever saying anything remotely like that. Care to copy and paste what you accuse him of saying?

    We have had about 1 degree of warming thus far, and nobody has ever claimed such a thing would cause cause significant migrations of people, and surprise surprise we havent seen any. So you have just created huge, boring, tatty old strawman.

    We have seen some very small pacific island communities partly relocate due to sea level rise thus far, and some quite noticeable sea level rise impacts In Florida. Google it. And we have already seen heatwaves increase in frequency and intensity, and level 5 hurricanes increase in number off Americas coast.

    If we get over 2 degrees of warming, the frequency and intensity of heatwaves is expected to become seriously concerning and will lead to life threatening conditions through tropical regions as below:

    https://www.theguardian.com/environment/2017/aug/02/climate-change-to-cause-humid-heatwaves-that-will-kill-even-healthy-people

    The more warming above 2 degrees, the worse it gets, obviously. I think this could lead to significant migration from tropical regions of the world to cooler climates. This probably won’t happen in a place like Florida because people will just spend more on air conditioning, but people in poor tropical countries cant always afford this.

    It’s a potentially grim huminatarian picture and mass migrations cause all sorts of geo political problems as we have seen recently in the middle east / Europe. It’s made worse by the potential for tropical cyclones to become more frequent and intesne at the same time and same places, and many pacific islands are also particularly susceptibe to sea level rise, so its a triple blow for them.

    Since you claim to be left leaning and have a bleeding heart for poor people, you might want to consider all this. And there I will leave it for now. I’m only bothering to put in the effort to respond because other people might find the guardian article interesting. Don’t think its just for you and your trolling.

  17. 167

    #165, Victor–

    I must invoke the Stravinsky clause again: “I don’t wish to criticize, etc., etc.” However, let’s clear one thing up. Obviously, science and logic are very difficult for you, Victor, but maybe you’ll do better with a syntactic issue. So, back to your #134:

    K: No, one would expect to see the more extreme effects in regions where the *change* in temperature is most marked, i.e., the Arctic.

    V: So “the Arctic” maintains a database, telling it how much its temperature has changed over the last several years? Pray tell, how does it do that? And as for that change being “most marked” in the Arctic . . .

    Obviously–perhaps even to you?–it is not the Arctic that maintains databases, but human scientists. They do so in order (inter alia) to be able to discern “where the *change* in temperature is most marked.”

    Definitions:

    marked
    /märkt/

    1. having a visible mark.
    “plants with beautifully marked leaves”
    (of playing cards) having distinctive marks on their backs to assist cheating.
    Linguistics
    (of words or forms) distinguished by a particular feature.
    “the word “drake“ is semantically marked as masculine; the unmarked form is “duck.””

    2. clearly noticeable; evident.
    “a marked increase in sales”

    Obviously, in context, the second sense is the relevant one. So, temperature change is most “clearly noticeable,” most “evident”, in the Arctic, where its magnitude has been roughly double that of the rest of the planet. This is thanks to the tireless labors of numerous scientists compiling those databases, since without those efforts, we would not know how much warming had occurred.

    This is shown graphically in such places as this:

    https://data.giss.nasa.gov/gistemp/maps/index.html

    So, let me again try to dumb it down sufficiently that you can actually understand it, instead of concluding in your incomprehension that I must not know what I’m talking about:

    Temperature-sensitive changes in extreme weather are a function not primarily of the temperature at a particular location, but of the *change* in temperature at that location.

    For example, the link above shows that north of 79 degrees N latitude, warming has exceeded 3 C, with respect to a 1951-1980 baseline. That’s the largest magnitude of warming seen anywhere. The least is south of 83 degrees south, on the Antarctic ice sheet (0.19 C), with another significant low in the band from 45 to 55 S (0.25-0.31 C).

    I don’t think I can make it simpler than that. And remember, I’m going to considerable lengths here to answer in good faith–albeit by now with an irritation that I’m not bothering to mask–a question that *you asked.*

  18. 168
    Piotr says:

    163 Kevin McKinney says about #160, Mack: A ‘lovely theory slain by ugly fact.’

    Or more precisely: a full of himself ignoramus^* – got slain by the very person he thought he was slaying (see BPL # 162).

    Lovely job, BPL.
    —-
    ^* a full of himself ignoramus to BPL, examples only from one post:
    -“The first [second, big] mistake you’ve made”
    – “you are following Trenberth’s looney Earth Energy Budget diagrams showing only 161 w/sq.m absorbed at the Earth’s surface…”
    – “you are confused”
    – “Anything else you need to know, BPL?”

    Me, me, me! Mack, how does it feel to have your ass handed to you, just when you thought it were the others who made fools of themselves? Ignorance is one thing, ridiculing others based on your own ignorance – quite a different one.

  19. 169
    Ray Ladbury says:

    Not to feed the troll, but one needs to be careful in answering any question from Weaktor. He tends to ignore or even switch between definitions of terms. He asked if we see more severe weather effects in the tropics. Now, if what he is asking about is climate–we certainly see more severe weather there. There is really no analog to Tropical Storms at temperate latitudes, and even a run of the mill tropical rain tends to put a Midwest gullywasher to shame. However, that is not especially germane to what happens due to climate change.

    The energetics of weather phenomena are complicated. Release of latent heat as water changes phase may play a more important local role than local insolation. I do not expect Weaktor o understand such subtleties, just as I do not expect him to comprehend the scales of the effects and systems under discussion. He doesn’t care enough about understanding. What I expect is that he will do what he has always done–exploit ambiguities in the replies to him in out of context copy-pasta to make it appear that everyone is as clueless as he is. That is why it is criticalto be precise if you do choose to engage with him.

  20. 170

    #168, Piotr–

    Absolutely right, Piotr!

    But let me underline the point I was trying to make, and fill out the context a bit more, too.

    Mack’s notion–which I ironically called a “lovely theory,” alluding to an epigram of Thomas Huxley’s–suffers from completely neglecting frequency.

    BPL said, correctly:

    You’ve merely taken a too-low emissivity and compensated for it with a too-high insolation.

    And the “ugly fact”–from Mack’s perspective, and as you and many others here know perfectly well, but apparently Mack does not–is that the “emissivity” and the “insolation” are in very distinct frequency bands!–or, to phrase it conversely, have very distinct ranges of wavelengths.

    (Some may appreciate a graphic illustrating this fact; if so, the second figure here should serve. As one can see, solar radiation lies roughly from 0.2 nm-2 nm, whereas Earthly thermal radiation spans something like 3-70 nm.)

    Further, these ranges are well-constrained by measurement at the surface, as my reference to pyranometers was intended to convey. There’s a history of measurement of solar and atmospheric radiation that goes back deep into the 19th century.

    In fact, I have written about that at some length, here:

    https://hubpages.com/education/Fire-From-Heaven-Climate-Science-And-The-Element-Of-Life-Part-Two-The-Cloud-By-Night

    It’s an incomplete survey, but I think will be eye-opening for many, as it traces some of the thread of the research perhaps a bit less well-known in relation to climate science history. Significant researchers I covered in relative depth in the article:

    –William Charles Wells (1814)
    –Anders Knut Angstrom–not his famous grandfather, Anders J. Angstrom, nor yet father Knut Angstrom, the scientific opponent of Svante Arrhenius! (1918)
    –W.H. Dines (1929)
    –Guy Callendar (1938)
    –Walter M. Elsasser (1942)

    Mack had remarked on “the real,measured 1360 watts /aq.m that exists at the TOA…” That leads me to think he is unaware–like a great many denialati who, well, deny that any such thing can exist–that “back radiation” is not some sort of invention by contemporary computer modelers, but rather a reality that has been under empirical study since the day of the Napoleonic wars.

    In fact, that empirical study was a necessary *prerequisite* for the development of numerical modeling of climate and weather in the first place.

  21. 171
    Barry Finch says:

    Since the comments concentrated on the so-called “greenhouse effect” rather than AMOC and nobody else mentioned the FTIR spectral analysis from the IRIS and HIRS infra-red spectrometer instruments on some of the Nimbus satellites:
    —————————
    Nimbus-1 (1964 – 1964)
    Nimbus-2 (1966 – 1969)
    Nimbus-3 (1969 – 1972)
    Nimbus-4 (1970 – 1980)
    Nimbus-5 (1972 – 1983)
    Nimbus-6 (1975 – 1983)
    Nimbus-7 (1978 – 1994)
    Nimbus-3 (1969 – 1972) IRIS-B Infra-Red Interferometer Spectrometer – B
    Nimbus-6 (1975 – 1983) HIRS High-resolution Infra-Red Sounder
    —————————
    Example measured FTIR power flux vs wave-length spectra with the notches, H2O broad-band suppression & atmospheric window at:
    http://climatemodels.uchicago.edu/modtran/modtran.doc.html (IRIS-C spectrum on the Nimbus 3 satellite over the Sahara Desert to demonstrate the U.S. Armed Forces MODTRAN model’s general accuracy)
    https://publishing.cdlib.org/ucpressebooks/view?docId=ft8r29p2m6;chunk.id=d0e1726;doc.view=print (Sahara Desert as observed by IRIS-D instrument on the Nimbus-4 satellite)
    https://www.youtube.com/watch?v=Oog7-KOtpEA&t=1713s at 18:07 (4 FTIR samples for western tropical Pacific Ocean, Sahara Desert, Antarctica & southern Iraq)

  22. 172
    Mack says:

    @162 BPL

    You need to quietly sit down a read over again my comment @160. See if you can understand what I’ve said…. it’s pretty simple… I think most of the other readers can follow it.

  23. 173
    Victor says:

    166
    nigelj says:

    “We have had about 1 degree of warming thus far, and nobody has ever claimed such a thing would cause cause significant migrations of people, and surprise surprise we havent seen any. So you have just created huge, boring, tatty old strawman. . .

    If we get over 2 degrees of warming, the frequency and intensity of heatwaves is expected to become seriously concerning and will lead to life threatening conditions through tropical regions as below:

    https://www.theguardian.com/environment/2017/aug/02/climate-change-to-cause-humid-heatwaves-that-will-kill-even-healthy-people

    The more warming above 2 degrees, the worse it gets, obviously.”

    V: Average Weather in Miami Florida, United States (https://weatherspark.com/y/18622/Average-Weather-in-Miami-Florida-United-States-Year-Round ):
    “In Miami, the summers are hot, oppressive, wet, and mostly cloudy and the winters are short, comfortable, humid, windy, and mostly clear. Over the course of the year, the temperature typically varies from 62°F to 90°F and is rarely below 50°F or above 92°F.”

    Average Weather in Anchorage Alaska, United States ( https://weatherspark.com/y/252/Average-Weather-in-Anchorage-Alaska-United-States-Year-Round):
    “In Anchorage, the summers are cool and mostly cloudy and the winters are long, freezing, snowy, and partly cloudy. Over the course of the year, the temperature typically varies from 13°F to 68°F and is rarely below -8°F or above 75°F.”

    I wasn’t referring to the piddly 2 degree increase that’s worrying you so much. I was referring to the temperature differentials we typically find on a normal basis in different regions of the world. E.G., the typical high in Miami is reported (see above) at 90°F while in Anchorage it’s 68°F, a difference of 22 degrees F (12 degrees Celsius). If temperature were as significant a factor in precipitating extreme weather-related events, we’d thus expect to see approximately 6 times more fires, droughts, extreme rainfall, species extinctions, etc. in Florida than the Arctic.

    167
    Kevin McKinney says:

    I must invoke the Stravinsky clause again: “I don’t wish to criticize, etc., etc.” However, let’s clear one thing up. Obviously, science and logic are very difficult for you, Victor . . .

    V: Stop with the posturing already, Kevin. It’s getting old. And besides it makes you look weak. I’ve consistently scored within the highest percentiles of the Universities I’ve attended, never had to pay tuition thanks to numerous scholarships, fellowships, assistantships; was offered a sizeable fellowship to Harvard grad. school (which, as it happens, I turned down in favor of another institution), have published widely in a variety of peer-reviewed and non peer-reviewed journals, including scientific journals, have myself been a peer-reviewer — and no one familiar with my work has ever questioned my intelligence. If you see me as some sort of dunce that reflects on YOU.

    K: No, one would expect to see the more extreme effects in regions where the *change* in temperature is most marked, i.e., the Arctic.

    V: So “the Arctic” maintains a database, telling it how much its temperature has changed over the last several years? Pray tell, how does it do that? And as for that change being “most marked” in the Arctic . . .

    K: Obviously–perhaps even to you?–it is not the Arctic that maintains databases, but human scientists. They do so in order (inter alia) to be able to discern “where the *change* in temperature is most marked.”

    V: So you still don’t get it. There are plenty of databases but “the Arctic” itself doesn’t maintain one. The Arctic itself. Get it? And if the Arctic itself has no way of keeping track of the changes that mean so much to you then how could those changes make extreme events more likely? Obviously, forest fires are produced by current conditions, not some historical record of temperature change.

    K: Temperature-sensitive changes in extreme weather are a function not primarily of the temperature at a particular location, but of the *change* in temperature at that location.

    For example, the link above shows that north of 79 degrees N latitude, warming has exceeded 3 C, with respect to a 1951-1980 baseline. That’s the largest magnitude of warming seen anywhere. The least is south of 83 degrees south, on the Antarctic ice sheet (0.19 C), with another significant low in the band from 45 to 55 S (0.25-0.31 C).

    I don’t think I can make it simpler than that. And remember, I’m going to considerable lengths here to answer in good faith–albeit by now with an irritation that I’m not bothering to mask–a question that *you asked.*

    V: I’m not sure you can make it more simple MINDED than that. So yes, Arctic temperatures have warmed. But forest fires, as I’ve continually reminded you, are not caused by what happened the previous year or the years before that, so the difference could not possibly be the cause. And you accuse ME of not understanding basic science!

  24. 174
    Piotr says:

    Mack @172 do @162 BPL: “You need to quietly sit down a read over again my comment @160. See if you can understand what I’ve said….”

    If he didn’t understand you, how was he able to hand you your ass, that way he did in @162? ;-)

    Mack@172: “it’s pretty simple… I think most of the other readers can follow it.”

    Yes, it’s pretty simple – everybody understood you perfectly well – that you are full of yourself ignoramus, who not only is not aware of his own ignorance, but on his ignorance builds derisive comments about others and is utterly incapable of comprehending even simple arguments, with which the readers tried to help him to understand where he went astray:

    1. you confuse solar radiation at the top of the atmosphere (~340 W/m2) with the one reaching the Earth’s surface (184 W/m2, out of which 23 are reflected, leaving 161 W/m2 absorbed by the Earth surface). Even though it is only the latter that is relevant to YOUR OWN ARGUMENT (if you don’t know your own argument – you argued that the amount of the solar energy absorbed by the Earth’s surface is equal to the amount of IR emitted from the Earth surface. 340 W/m2 at top of the atmosphere are IRRELEVANT here).

    2. You have no idea about the concept of emissivity you use – you think that only things like “black asphalt” can have emissivity near 1, and claim: “The Earth’s total emissivity has been measured at 0.82”, NOT providing ANY source for your claim (BPL did for his).

    3. Even if you didn’t want to check out the source given to you by BPL, one quick search on Internet and voila:
    https://www.jpl.nasa.gov/spaceimages/details.php?id=PIA18833

    ” the surfaces with emissivities less than 0.85 are typically restricted to deserts and semi-arid areas. Vegetation, water and ice have high emissivities above 0.95 in the thermal infrared wavelength range.”

    Most of the Earth’s surface is NOT “deserts and semi-arid areas”, but “vegetation, water or ice”. “We are a blue planet”. Rings a bell?

    And since the vast majority of Earth’s surface has the emissivity > 0.95, then the global average CANNOT possibly be “0.82” as you claim.

    That’s why why BPL @162 summarized the fallacy of your “calculations”: you compared 2 terms in which:

    – you greatly OVERESTIMATED one term (by your DOUBLING of the amount of solar radiation absorbed the Earth surface from 161 W/m2 to your “340 watts/sq.m”.

    – and then UNDERESTIMATED the other term – the IR emissions from the same Earth’s surface (by using emissivity of 0.82 INSTEAD >0.95).

    When _I_ read people who know more than me on something, and there is some point that I don’t understand – my first assumption is that probably I have missed something, NOT that the people who know much more than me … are morons and made an obvious mistake that only the brilliant me was able to see. If I still can’t figure out what’s the problem – I would ask politely the author where he/she get the data from, or to explain his/her assumptions or argument.

    You are the opposite – in the area you obviously know very little about (see points 1-3 above) – your STARTING assumption is that … you must be brilliant and it is the people who publish in peer-review papers on the subject, like Trenberth, who are the idiots:

    “You are following Trenberth’s looney Earth Energy Budget diagrams showing only 161 w/sq.m absorbed at the Earth’s surface…. ” (c) Mack @ 160

    To not know something is not necessarily a shame, it all depends on whether we are aware of our and on how do we respond to our ignorance: with humility, or like you – with contempt and arrogance toward those who know more.

    ===
    Piotr

  25. 175
    nigelj says:

    Victor @173

    “I wasn’t referring to the piddly 2 degree increase that’s worrying you so much. I was referring to the temperature differentials we typically find on a normal basis in different regions of the world. E.G., the typical high in Miami is reported (see above) at 90°F while in Anchorage it’s 68°F, a difference of 22 degrees F (12 degrees Celsius). If temperature were as significant a factor in precipitating extreme weather-related events, we’d thus expect to see approximately 6 times more fires, droughts, extreme rainfall, species extinctions, etc. in Florida than the Arctic.”

    No we wouldn’t expect to see 6 times more fires in florida than the arctic. The number of fires is related to things like like arson and lightening strikes which is quite independent of temperatures. Temperatures effect areas burned and in that respect warm climates like Australia have pretty large areas burned compared to arctic regions. But it also depends on the availability of fire fighting resources, and vegetation gets adapted to local temperatures, so comparisons are difficult, so leave it to the experts and read the formal studies!

    And we would not expect to see 6 times more species extinctions in warm areas than cold areas, because species become adapted to local temperature. Species can’t adapt to the change of temperatures caused by the speed of global warming! Its a rate of change problem.

    And so on.

    “V: So you (KM) still don’t get it. There are plenty of databases but “the Arctic” itself doesn’t maintain one. The Arctic itself. Get it? And if the Arctic itself has no way of keeping track of the changes that mean so much to you then how could those changes make extreme events more likely? Obviously, forest fires are produced by current conditions, not some historical record of temperature change……V: I’m not sure you can make it more simple MINDED than that. So yes, Arctic temperatures have warmed. But forest fires, as I’ve continually reminded you, are not caused by what happened the previous year or the years before that, so the difference could not possibly be the cause. And you accuse ME of not understanding basic science!”

    Does anyone know what Victor is getting at? I think the issue is warming over time causes changes to the weather, due to more energy in the system locally. Victor, why would more energy in the system not have impacts on the weather?

    And the northern hemisphere is warming faster than the southern hemisphere so you would expect to see more changes in the weather in the north. Although energy is transported around so much that the difference gets diluted. But northern Europe near the arctic has certainly started to experience more intense heatwaves, and other phenomena, some very big ones more so than the lower part of the southern hemisphere. Decline of glaciers has also been more dramatic in Europe than in the southern hemisphere.

    I really cant see what exactly Victor is arguing about.

  26. 176
    nigelj says:

    BPL @ Piotr, thanks for your illuminating and convincing rebuttals of Macks cranky ideas and maths. I think the guy has some “issues”.

  27. 177
    Astringent says:

    V@ too many places to count, keeps saying ‘the Arctic doesn’t maintain a database’, demonstrating explicit ignorance about the many ways it literally does; over short terms in the ensembles of vegetation and growth rings in trees, over the medium term in lake sediments and geothermal gradients, and over the longer term by looking at things like pollen assemblages in sediments, or isotopic composition of the shells of molluscs etc.

  28. 178
    Piotr says:

    Victor: “So you still don’t get it. There are plenty of databases but “the Arctic” itself doesn’t maintain one. The Arctic itself. Get it? ”

    Huh? What have you been trying to express, Victor? Perhaps you could ask somebody to help you to translate your thoughts into English? Or into logical? WHY would “maintaining databases” by “the Arctic itself” be the … necessary condition for the ability to say anything about the climate in the Arctic?

    Would your thinking apply elsewhere – e.g, that to say anything about any process happening on the Sun, one needs “databases maintained by the [Sun] itself”?
    (Maybe the guys from the Empire of the Sun would be of help here? https://www.youtube.com/watch?v=hN5X4kGhAtU ?)

    What’s wrong with the databases of the Arctic data collected and maintained not by “the Arctic itself”, but by, say, the National Snow and Ice Data (sic!) Center?
    https://nsidc.org/cryosphere/arctic-meteorology/climate_change.html

    Or if you meant the need for traditional knowledge – how about you move your ass and do some search in support of _your own_ claims? It’s not that difficult, you know – I typed: “arctic changes local news” and voila – the first hit:
    https://www.cbc.ca/news/canada/north/arctic-transition-new-climate-1.5724837

  29. 179
    Victor says:

    nigelj: “Does anyone know what Victor is getting at? I think the issue is warming over time causes changes to the weather, due to more energy in the system locally. Victor, why would more energy in the system not have impacts on the weather?”

    V: It can and does, certainly. But the full range of typical temperatures across the globe is far greater than the miniscule rise in global averages over the last hundred years or so. If a rise in 1 (or 2) degrees centigrade is capable of doing all the extreme damage continually noted by climate alarmists, then we’d expect to see a vast difference in temperature-induced damage between high and low latitudes when we examine Earth’s history. I’ll concede that this does seem to be the case where hurricanes are concerned, as they are far more likely to arise in tropical regions. Other than that, however, there doesn’t seem to have been a notable trend, historically, for more intense and dangerous weather-related events in the lower latitudes, where temperatures are typically far higher than those in the upper latitudes. All else being equal, of course, as conditions other than temperature can, as you say, certainly vary from region to region.

  30. 180

    Victor, #173–

    3 things:

    1) Victor, you are essentially arguing that because ethnomusicologists notate folk music, therefore a particular folk music can never change. But databases, like musical notation, reflect real phenomena, which can and do change over time. (Hopefully, the notation will then change appropriately.)

    And those changes in the primary reality can and do have real-world consequences–such as drier conditions leading to more fire activity through straightforward, well-understood mechanisms.

    Obviously, forest fires are produced by current conditions, not some historical record of temperature change.

    Equally obviously, those “conditions” have changed, ergo fire characteristics change, too. Which we, who are not in the Arctic, know about because of databases and other forms of documentation. *We* need them; the Arctic does not. The Arctic reality on the ground is the primary phenomenon; it doesn’t need the ‘finger pointing at the moon.’

    2)

    If you see me as some sort of dunce that reflects on YOU.

    Duns Scotus, for whom the term “dunce” is allegedly eponymous, was a brilliant scholar. I’m perfectly willing to stipulate you have native ability, but in these matters you are adopting an argument (for whatever reason) that is transparently idiotic–the very definition of willful stupidity. And yes, to use your word, it’s getting very “old”.

    Short version: if you don’t want to be perceived as a dunce, stop acting like one. All you really need to do is set aside the assumption that you already know it all, and listen in good faith.

    3)

    But forest fires, as I’ve continually reminded you, are not caused by what happened the previous year or the years before that, so the difference could not possibly be the cause.

    Uh, the *previous year’s fires* obviously *were* caused “caused by what happened the previous year.”

    It would probably help if you started to listen to yourself, too.

  31. 181

    nigel, #175–

    Does anyone know what Victor is getting at? …I really cant see what exactly Victor is arguing about.

    In my opinion, nigel, that’s because you are a pragmatic and sensible person. So you are baffled by arguments that are, shall we say, inappropriately Scholastic.

    Victor is saying that because the Arctic can’t *know* that it is changing, therefore it can’t change. It doesn’t sound as dumb as that when he says it, but that’s what the argument reduces to, shorn of the bafflegab.

    But knowledge in the formal human sense, of course, isn’t actually required. The Arctic today IS the change. Our formal knowledge is just ‘the finger pointing at the moon’–a representation.

    I can’t forbear this poetic statement of the concept:

    All instruction is but a finger pointing to the moon; and those whose gaze is fixed upon the pointer will never see beyond. Even let him catch sight of the moon, and still he cannot see its beauty.

    I suspect Victor won’t ‘look at the moon’ because his a priori conviction is that the finger is pointing in completely the wrong direction. He can’t–won’t–give up that conviction… even though to an outside observer it makes him look thoroughly ridiculous.

  32. 182
    William B Jackson says:

    #175 “I really cant see what exactly Victor is arguing about.” I think it possible that neither can Victor. Oh and as to Mack, is it possible he is just a less well “educated” Victor? I am not a scientist but unlike some I can see where trends have taken us in my 70 some years on earth, and do not feel that I can second guess the reality and the science which seem to fit so well.
    You can wish things were other wise but that doesn’t make it so!

  33. 183
    nigelj says:

    Victor @79, ok, but the low latitudes climates have far more than just hurricanes to worry about. You get life threatening heatwaves, crop failures related to heat stress, water shortages, desertification, costs of air conditioning, and it looks like larger areas burned in forest fires. These are at the very least significant differences.

    Of course this ignores other problems caused by climate change like sea level rise, increased flooding, increased rates of biodiversity loss. And “a piddly 2 degrees of warming” is associated with some pretty rapid sea level rise in past climates. I think we might be opening a pandoras box of troubles. And it ignores the fact that its not just the temperature that is a problem, its the speed at which it changes that makes adaptation harder.

    I think we could probably live with any one of these problems taken in isolation, but not all of them added together. That is what concerns me most.

    ——————————–

    KM @181, strange stuff indeed. Oddly enough I was a bit of a latin scholar at school, but all I can remember now is “amo, amas, amat”.

  34. 184
    nigelj says:

    KM @181, “amo, amas, amat” means “I love, you love , he / she loves”. It was our first lesson in latin, so I guess its stuck. I think the rest would come back to me if I flicked through a text. I found latin and the related roman culture and political history quite interesting.

  35. 185
    John Pollack says:

    Victor stated most clearly @179 “But the full range of typical temperatures across the globe is far greater than the miniscule rise in global averages over the last hundred years or so. If a rise in 1 (or 2) degrees centigrade is capable of doing all the extreme damage continually noted by climate alarmists, then we’d expect to see a vast difference in temperature-induced damage between high and low latitudes when we examine Earth’s history.”

    I will address this misconception in two parts. First, some straight meteorology. A 1C rise in temperature as a global average is not the same everywhere. The Arctic is warming faster than the tropics, for example.

    Even a uniform 1C rise would vary in effects according to time, place, and base temperature. One big reason is that the ability of air to hold water vapor rises exponentially with warmer temperatures, about 7 percent /1C.
    At -30C, air can hold only as much water vapor as carbon dioxide. At 0C, a kilogram of air will hold 3.8 grams when saturated at sea level pressure. At 25C, it will hold 20.4 grams. That’s Miami-type humidity.

    The amount of energy that it takes to heat dry air is essentially independent of temperature. However, water vapor has a very high potential energy content. So, the warmer it is, the greater the amount of energy that saturated air can provide to weather systems. In fact, to raise air from 24C to 25C requires only 1/3 as much energy as it does to saturate that air at the new temperature. Conversely, when air is cooled by lifting to condensation, the potential energy is released. This is what a hurricane does, in an organized fashion. It’s also why the strength of hurricanes is so sensitive to ocean temperature. Mid latitude storm systems run on a combination of energy provided by a horizontal temperature gradient and energy provided by condensation of water vapor. The effects of a 1C temperature rise are not so dramatic, overall. However, in both cases the addition of energy from extra water vapor results in enhanced vertical motion. This results in more intense precipitation. However, it also has to be compensated by greater sinking motion around the periphery of the storm. This results in more warming and drying surrounding the weather system. This can be local, such as the downdraft around a thunderstorm. It can also be large scale, such as the subtropical high pressure areas that are associated with very high temperatures and drought if they persist over an area. This is what underlies the seemingly contradictory idea that warming can produce both greater precipitation and greater drought. Note that if the weather systems move enough, precipitation may still be well-distributed. But, if they become stuck or slow-moving, some places are getting hit with extra-heavy precipitation, while others experience intense drought.

    The bottom line is that not all storms will be strengthened by warming. However, storms that depend on the organized release of a lot of condensation energy from water vapor will be. That especially includes hurricanes and thunderstorms, but can include mid-latitude cool season storms. Storms will be liable to produce heavier precipitation, with greater drying potential between storms. These changes aren’t necessarily disasters, but they have bad consequences when interacting with humans and our infrastructure, and also the natural world. That’s part 2.

  36. 186
    John Pollack says:

    Part 2 The interactive effects of warming

    As I outlined in Part 1, rising temperatures allow the atmosphere to hold exponentially greater amounts of water vapor. The energy released when it precipitates out produces stronger vertical motions, more intense precipitation, and potentially more intense droughts. These effects interact both with the natural environment and the built infrastructure that humans depend upon, producing more frequent disasters than a stable climate.

    In general, humans build their infrastructure to protect themselves from expected weather extremes where they live, resources allowing. Problems multiply rapidly into a disaster when the extremes reach an unexpected intensity. Sudden extremes, such as flooding or violent winds, are the most dramatic and immediately life threatening. Both are enhanced at higher temperatures.

    Extremes which develop over a longer time period, such as droughts, can be just as disastrous. Typically, droughts lead to crop failures, and escalating confrontation over remaining water supplies, which tend to be monopolized by whatever political groups or entities that have the most power in the drought area. Historically, prolonged droughts are thought to have undermined entire civilizations.

    Other consequences of long-term change can be more subtle, but very important. Warming temperatures will change the vegetation, hydrology, and animal inhabitants of a region. Vegetation is attacked by a combination of unfavorable weather, insects, and possibly invasive species. When there is a drought, fires feed on dead vegetation. When there is excess precipitation, flooding happens faster on denuded land, as well as excess sedimentation and landslides. In the U.S., a water control system largely built to control 20th century floods and droughts is being overcome by the more severe events of the 21st century. Not all at once, but in one expensive disaster after another. Sea level rise is another long term problem, but disasters still result from unplanned-for storm surges.

    Finally, it is worth mentioning that some weather can exceed human tolerance. Most of us rely extensively on heating and air conditioning to keep ourselves comfortable, but many people in hot climates are poor, and have to work outdoors. The combination of temperature and humidity in parts of the Mideast and Southeast Asia are already at the outer limits of tolerance, but people still have to be outside. Even in the U.S., most of the population increase in the “sun belt” states came after the advent of household air conditioning. Heat waves can still result in mass deaths where people are unprepared, or too poor to afford air conditioning.

  37. 187
    Adam Lea says:

    Ray Ladbury@169: “There is really no analog to Tropical Storms at temperate latitudes…”

    The closest you can get is autumn/winter windstorms. Historically, European windstorms have not been far behind Atlantic hurricanes on average for insured losses. The wind speeds might be lower than a strong tropical cyclone but their winds are spread over a much larger area. From 1970 to around 2015 they ranked as the second highest cause of global natural catastrophe insurance loss (behind U.S. hurricanes).

    A couple of notable UK examples:
    https://www.youtube.com/watch?v=9TbwH-Kb8bs&t=323s&ab_channel=MarkPBerne
    https://www.youtube.com/watch?v=gUWufMuidD8&ab_channel=anthonyc

    Unlike hurricanes, these are not fueled by warm sea surface temperatures, they are fueled by baroclinic instability through the temperature difference between the sub tropics and the poles. How these storms will change in frequency and intensity under future climate change is somewhat uncertain.

  38. 188

    V 179: If a rise in 1 (or 2) degrees centigrade is capable of doing all the extreme damage continually noted by climate alarmists, then we’d expect to see a vast difference in temperature-induced damage between high and low latitudes when we examine Earth’s history.

    BPL: No, you’re assuming only the difference in latitude matters. Heat is redistributed among latitudes by winds (especially the great atmospheric cells such as the Hadley circulation) and ocean currents. Otherwise the equator would be much hotter than it is, and the poles much colder.

  39. 189

    Victor, #179–

    But the full range of typical temperatures across the globe is far greater than the miniscule rise in global averages over the last hundred years or so. If a rise in 1 (or 2) degrees centigrade is capable of doing all the extreme damage continually noted by climate alarmists, then we’d expect to see a vast difference in temperature-induced damage between high and low latitudes when we examine Earth’s history.

    No, because in Victor’s words:

    If temperature were driving extreme weather then norms associated with particular localities would have reflected that.

    A “heat wave,” for example, is not defined relative to a fixed global temperature, but to “local norms”:

    While definitions vary, a heat wave is usually measured relative to the usual weather in the area and relative to normal temperatures for the season. Temperatures that people from a hotter climate consider normal can be called a heat wave in a cooler area if they are outside the normal climate pattern for that area.

    95F is ‘really hot’ in Sault Ste. Marie (~46.5N); in Camden, SC (~32.4 N), not so much. And if that’s true for the people, it’s true many times over for the flora and fauna. So, “norms associated with particular localities” very much are reflected in extreme weather–just not the way Victor was thinking.

    The greater the departure from the conditions to which people, plants and animals are adapted, the more “extreme” the conditions are. And as stated, the greatest departure (for temperature, at least) is in the Arctic.

    It’s also worth mentioning that while the magnitude of shift in temperature regimes does indeed seem ‘piddly’ compared with the gamut of Terrestrial temperatures, a more meaningful assessment would lie the relation of a particular temperature shift to particular thermal boundary conditions–most notably, the freezing/melting point of water, but there are many others.

    A few random ones:

    –the ‘turnover point‘ for temperate lakes: varies by depth, etc., but for temperate lakes, often ~10-13 C
    –the critical point for salt-marsh-to-mangrove conversion
    –thermal stress point for plants: (varies across biomes)
    –and, of course, the guaranteed thermal lethality point for humans: ~35 C (wet bulb)

    Hard limits can provide exquisite sensitivity to small temperature shifts: the most significant inch of flooding is always the one that takes the water level above your threshold.

    There’s also a second-order aspect to this, which is timing: Small shifts in mean temp can translate into, for instance, shifts of weeks in mean freeze onset date. (Or spring breakup: c.f., Nenana Ice Classic.) These can be of great biological/ecological significance. To take a local (to me) example, peach cultivation is economically very important in South Carolina. But peaches need chill hours during the winter to set fruit. Increasingly, that’s become a challenge here. There’s a solution, which is to convert to varieties that need fewer chill hours. But it’s slow and expensive for the orchardists.

    It’s also worth noting that variability is still sufficient to bring lethal freeze events as well. 2017, for instance, suffered from both effects: warmth during winter months inhibited fruit, and then there was a killing cold snap in March. End result: loss of ~90% of the crop.

    Climate adaptation efforts are underway via plant-breeding research, but it’s difficult and slow:

    And user acceptance is crucial, and non-trivial:

    Growers can be hesitant to adopt the bleeding edge of tree varieties, however, especially when they don’t produce fruit for their first three years of growing.

    Yonce said that he wasn’t convinced some newer cultivars had been reliably proven, and others were too expensive. He’s replanting between 5 and 10 percent of his roughly 4,000 acres every season, but each tree represents a long commitment.

    “You have to convince that grower to basically take a 10-year investment in that cultivar for it to pay off,” said Kyle Tisdale, director of the S.C. Peach Council.

  40. 190
    Piotr says:

    Kevin McKinney (181):”Victor is saying that because the Arctic can’t *know* that it is changing, therefore it can’t change.”

    so because Victor is not able to understand that he is wrong, then he can’t be wrong???

  41. 191
    Victor says:

    Kevin: Victor is saying that because the Arctic can’t *know* that it is changing, therefore it can’t change. It doesn’t sound as dumb as that when he says it, but that’s what the argument reduces to, shorn of the bafflegab.

    V: Oh my. THAT’S what you think I said? Really I don’t know how to respond because no matter what I say you’ll get it wrong.

    One more try: To the extent that Arctic fires are affected by temperature, they are affected by the temperature prevailing at the time of, or just prior to, such fires, NOT by temperatures that prevailed during previous years. As should be obvious. Why is that so difficult for you to understand? Whether the Arctic changes from year to year has nothing to do with it.

    As for my principal point:

    “the full range of typical temperatures across the globe is far greater than the miniscule rise in global averages over the last hundred years or so. If a rise in 1 (or 2) degrees centigrade is capable of doing all the extreme damage continually noted by climate alarmists, then we’d expect to see a vast difference in temperature-induced damage between high and low latitudes when we examine Earth’s history.”

    I can’t put it more plainly than that. It ain’t rocket science folks. If you don’t get it you need help.

  42. 192
    Piotr says:

    Victor: “Oh my. THAT’S what you think I said? Really I don’t know how to respond because no matter what I say you’ll get it wrong”

    Ever thought that if everybody gets you wrong – then the problem may be not with … everybody?

    V: “the extent that Arctic fires [is] NOT [affected] by temperatures that prevailed during previous years. As should be obvious. Why is that so difficult for you to understand?”

    If previous year temperature reduced moisture in the soil and vegetation making, it will make them more flammable in the_next_ year. If milder winter in the past lead to massive tree kills by the increased populations of pests, this will make the forests more much flammable in _next years_ – see the recent massive in boreal forests of Western Canada, _many years_ after the explosion of tree-killing pine beetle and fungus it spreads? If the climate warms faster than the local vegetation can adapt to it, then you have more dead trees which make the forests more flammable. etc. “this should be obvious. Why is that so difficult for you to understand?” , eh ? ;-)

    V: As for my principal point: “the full range of typical temperatures across the globe is far greater than the miniscule rise in global averages over the last hundred years or so.”

    Principal, shmincipal – ecosystems have adapted to those differences over tens of thousands, or millions of years, not in DECADES!

    Your “principal point” is like saying that the orange crops in Florida cannot be possibly be damaged by a frost, because trees in Canada regularly survive much colder temperatures for much longer times. Apples and oranges, Vikki, or
    rather: spruce cones and oranges.

    So much for your glorious “principal point” on which you based you contemptuous comments about others. Seeing an imaginary straw in the eye of another, and missed a spruce pole in your own?

  43. 193
    Russell says:

    160

    It’sa shame to see Mack hide his light under a bushel while so many aspiring climate authors need mathematically zealous co-authors.

    Perhaps he should join forces — here’s a likely place for him to start

    https://vvattsupwiththat.blogspot.com/2020/10/new-monctkon-vaccine-cures-covid.html

  44. 194
    William B Jackson says:

    #191 I admit you have confused me, but I suspect you have confused yourself…even more!

  45. 195
    nigelj says:

    Victor @191

    “the full range of typical temperatures across the globe is far greater than the miniscule rise in global averages over the last hundred years or so. If a rise in 1 (or 2) degrees centigrade is capable of doing all the extreme damage continually noted by climate alarmists, then we’d expect to see a vast difference in temperature-induced damage between high and low latitudes when we examine Earth’s history.”……I can’t put it more plainly than that. It ain’t rocket science folks. If you don’t get it you need help.”

    And its been explained to you by numerous people that its just not that simple. There are differences as I said, low latitude tropical regions have more area burned in forest fires, more destructive storms , more heat stress and droughts than high latitudes. And climate change will make it worse of course. But crops and forests do become adapted to local conditions so the differences in damage are not necessarily large and all that energy in the tropics gets transported back to the poles as someone pointed out. Its not rocket science, so if you dont get it maybe you need help!

  46. 196

    piotr, #190–

    so because Victor is not able to understand that he is wrong, then he can’t be wrong???

    Well, not in his own mind, anyway.

    Victor, #191–

    One more try: To the extent that Arctic fires are affected by temperature, they are affected by the temperature prevailing at the time of, or just prior to, such fires, NOT by temperatures that prevailed during previous years.

    Yes, we agree on that.

    1) However, you wrote “the temperature prevailing at the time of, or just prior to, such fires…” is influential on fires.

    Does this apply to *all* times–that is, September 1880, or 1970, or 2020? If no, then why not?

    2) Let’s use some actual data as example. This is all based on GISTEMP, here:

    https://data.giss.nasa.gov/gistemp/maps/index.html

    (Note that I have not pre-selected these years with knowledge of what the results show–obviously, I picked the earliest and latest ones, with added a randomish one in the (late) middle.) So here are the anomalies @ 59N** for the Septembers I mentioned:

    1880: -0.03 C
    1970: -0.03 C
    2020: 1.38 C

    Subject to further investigation, and stipulating a connection between fires and temps as above, would you agree that we should expect that 2020 would see elevated fire activity in the 59N zone, as compared with 1880 or 1970? If not, why not?

    3) Above, I have described the difference in temperature at a given location over some span of time as the “delta” or “change” in temperature–for instance, the 1.41 C noted in the example. I have stated that this change in temperature thus drives changes in extreme events: 1880 temps drive 1880 fires, 1970 temps drive 1970 fires, and 2020 temps drive 2020 fires.

    But, of course, 2020 temps are different, as noted. Thus, changes in temperatures–the observed 1.41 C increase, for 59N–drive changes in fires, too, utterly without any spooky ‘action across time.’ This follows ineluctably from affirmative answers to the above, and–given affirmative answers–would seem to completely invalidate your statement that:

    Whether the Arctic changes from year to year has nothing to do with it.

    **(No, 59N is not quite actually Arctic; the Circle is a couple of degrees and a bit north of 60N. But I’m bending over backwards not to cherrypick exaggerated numbers. You can pick your own, if you like, on the GISTEMP maps. Doesn’t really matter in this context, anyway, as it’s all illustrative.)

  47. 197

    nigel, #183–

    OT, but hopefully fun.

    Oddly enough I was a bit of a latin scholar at school, but all I can remember now is “amo, amas, amat”.

    Well, you might get a smile out of this bit of doggerel then–I think it goes back to the 18th century, and IIRC was set to music for a class of drinking song called a “catch”.

    Amo, amas, I love a lass,
    As a tulip tall and slender.
    A cowslip’s grace is her nominative case,
    And she’s of the feminine gender!

    Some catches were very bawdy, but that one is at very worst just a tad insinuating.

  48. 198

    Victor, #189 (pt 2)–

    I wasn’t going to tackle this again, but…

    …the full range of typical temperatures across the globe is far greater than the miniscule rise in global averages over the last hundred years or so. If a rise in 1 (or 2) degrees centigrade is capable of doing all the extreme damage continually noted by climate alarmists, then we’d expect to see a vast difference in temperature-induced damage between high and low latitudes when we examine Earth’s history.

    No. Inter alia, because extreme weather is specifically local.

    Why ‘local’? Because genetic, physiological, and cultural adaptation inevitably fits inhabitants to places over time. We don’t primarily care about how hot the temperature is on a thermometer, but about how hot it effectively is for ourselves, our plants and animals, and even our things.

    In passing, it’s rather ironic that Victor insists on ‘localism’ with respect to time, but ‘universality’ with respect to place.

    (The other ‘why not’, of course, is the “delta-T, not T” piece I’ve been trying fruitlessly to explain.)

  49. 199

    #192, piotr–

    Yes, good points. The real world has ‘memory’, but it’s not symbolically mediated, it’s rather a causal chain connecting past events with future ones. You could even say the real world IS memory.

    Your post apparently contradicts some of what I said in #196–but only at a surface level. True, fires for instance occur in response to conditions at particular places and times. But it’s also true that, at a deeper level, the ‘conditions’ integrate past states into some sort of resultant. So, action across time–just not ‘spooky’ action.

  50. 200
    Al Bundy says:

    Kevin quoting Victor: If a rise in 1 (or 2) degrees centigrade is capable of doing all the extreme damage continually noted by climate alarmists, then we’d expect to see a vast difference in temperature-induced damage between high and low latitudes when we examine Earth’s history.

    AB: Not gonna read the source of the goop. Instead I’ll note that hundreds to thousands of feet of ice, as high latitudes sometimes see, is a tad more destructive than even the desertification of a lower latitude area.

    We’re not just talking “death to all”, but nature’s way of one-upping man’s paltry salting of the enemy’s soil. Much more permanent is scraping the rock clean. Look up the Canadian Shield.