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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

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

  1. 101
    Mack says:

    @ EP 97

    “…eliminating all the CO2, CH(4)sic3, N20 etc.would open up many radiation windows to space…”

    “Radiation windows to space” !!!?? aahahahahaha what a wacko we’ve got here.. nah…eliminating all those gases wouldn’t alter the global temperature in the slightest. Things would remain exactly the same, temperature wise. The only effect of removal of CO2 from the atmosphere would be a sterile planet….. probably temporary.
    Stick to poetry.

  2. 102
    zebra says:

    Victor #96,

    “This tells us nothing about temperature.”

    You finally got something right, and showed your ‘misunderstanding’ (whether real or rhetorically intentional).

    Temperature doesn’t cause anything, it is an effect, not a cause. Temperature is a proxy for energy, and that people even here are too lazy still to make that clear is disappointing.

    Say we have a ‘parallel Earth’ where everything is identical except for the energy in the climate system (we are Earth B, the other is Earth A, without the increase in energy we caused).

    Now, what is it you are “still confused” about? What predicted effect, caused by the increased energy on B, do you think is incorrect?

  3. 103
    nigelj says:

    Victor @96

    nigelj: “I think you might be confusing it all with the fact that a warming atmosphere makes vegetation drier and more prone to burning…”

    Victor: ” A drier atmosphere makes vegetation drier. If a warming atmosphere made vegetation drier then all those tropical rainforests would be deserts.”

    Nigelj: While drier air is obviously a factor so is warmer air. Let me just quote National Geographic:

    https://www.nationalgeographic.com/science/2020/09/climate-change-increases-risk-fires-western-us/

    “That might not seem like very much warming, but just a little can go a long way. Hot air, if it’s not at 100 percent humidity, is like a thirsty sponge: It soaks up water from whatever it touches—plants (living or dead) and soil, lakes and rivers. The hotter and drier the air, the more it sucks up, and the amount of water it can hold increases exponentially as the temperature rises; small increases in the air’s heat can mean big increases in the intensity with which it pulls out water. Scientists can measure this “vapor pressure deficit”—the difference between how much water the air holds and how much it could hold. If that deficit is cranked up for a long time, soils and vegetation will parch……A brief heat spell will dry out the smallish stuff or the already dead stuff—and maybe even some of the bigger tinder. Intense, record-breaking heat waves like the ones that encompassed the West during August and early September likely caused major crisping of burnable material, as the regional vapor pressure deficit and associated drought climbed to record levels….”

    Or carbon brief:

    https://www.carbonbrief.org/explainer-how-climate-change-is-affecting-wildfires-around-the-world

    “When temperatures are warmer than average, rates of evaporation increase, causing moisture to be drawn out from plants on the land. This drying can create “tinderbox conditions” – meaning that, if a fire is sparked, it can spread very quickly over large areas…….Similar conditions can also be created by long periods of drought, Santin tells Carbon Brief…”

    If you disagree, take it up with them.

    (It should be noted that warmer vegetation also catches fire more easily because the ignition point falls. And lower levels of relative humidity inland do mean drier air, and so vegetation is drier as people have pointed out.)

    So the bottom line is there is no contradiction. You seem to think you are the only person on earth who is skilled at spotting contradictions. I have to tell you I have observed that scientists are pretty good at this, and my understanding is they are trained in this sort of thing and general critical thinking.

  4. 104

    V 99: it’s hard to see how such a small increase in global temperatures (1 degree celsius) could have such a dramatic effect on not only rainfall but also droughts and forest fires.

    BPL: The mass of the atmosphere is about 5.148 x 10^18 kilograms. Its specific heat capacity at constant pressure is about 1,006 joules per kilogram per kelvin. 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.

  5. 105

    M 101: eliminating all those gases wouldn’t alter the global temperature in the slightest. Things would remain exactly the same, temperature wise. The only effect of removal of CO2 from the atmosphere would be a sterile planet….. probably temporary.

    BPL: Militant ignorance is ugly. I strongly suggest you pick up a textbook on atmosphere physics or radiative transfer, read it, and work the problems. Here are a couple of good ones:

    Houghton, J. 2002. The Physics of Atmospheres (3rd ed).

    Petty, G. 2006. A First Course in Atmospheric Radiation (2nd ed).

  6. 106
    Mack says:

    @102 Zebra

    “(we are Earth B, the other is Earth A, without the increase in energy we caused)”

    Earth A… Earth B ..whatever. Haven’t you noticed what the kids say on their protest banners ?….THERE IS NO PLANET B.
    Reality check …we are Earth A… full stop.

    “…,without the increase in energy we caused”

    Riiight, an increase in energy we caused. More energy…. the old more energy meme.
    This is the “more energy” stuff you got from Trenberth’s interview with the clown running the “Climate Crock” blog. More energy than what amount of energy? More energy since when? What’s the nature of the “more energy”…. linear, logarithmic, what? No numbers provided… just speculative, hand-waving tripe…. “we caused” ? ….no, Trenberth caused.

  7. 107
    Ray Ladbury says:

    I have coined a phrase for Weaktor’s latest tactic: He’s playing the why-baby. He is pretending to try to understand, but deliberately distorting the attempts to educate him under the guise of “just asking questions”–a.k.a JAQing off.

    This isn’t tough. Warm air is capable of holding more water if water is available. If warm air has more water, it will dump that extra water in larger precipitation events–hence more flooding… If water is not available, the relatively drier air will suck the water out of plants, animals, people, soil…exacerbating drought. In areas where air is humid, water is likely available, and air will have higher water content due to higher temperatures. In areas where air is dry, it is likely because little water is available, and the air will get drier.

    Now, really, how hard is that?

  8. 108
    MartinJB says:

    Victor (@99):

    Your first point is essentially an argument of incredulity. It is also based on misconceptions. First: The warming has been about 1.2c. Second: Over land, it has warmed about 2.0c.

    Your second point is just confused. Hydrology is a complex phenomenon based on temperatures, atmospheric and ocean currents, vegetation and existing water bodies. I would suggest you actually try learning a bit about it rather than taking uninformed exception to the conclusions of the scientific community on the subject. This might be a good starting point for you:

    https://www.gfdl.noaa.gov/climate-change-and-the-hydrologic-cycle/

  9. 109

    Victor, #99–

    1) “It’s hard to see…” Well–embedded incredulity aside–candidly, yes it is, because precipitation is a complicated business. (Disclosure: I certainly do not claim to understand all the convolutions affecting the relationship of rain and temperature. Hopefully we’ll hear more from folks truly well-versed in this.)

    But a starting point is Clausius-Clapeyron:

    …the August–Roche–Magnus equation implies that saturation water vapor pressure changes approximately exponentially with temperature under typical atmospheric conditions, and hence the water-holding capacity of the atmosphere increases by about 7% for every 1 °C rise in temperature.

    Don’t forget that the 1C rise is *global*. For land only, the observed rise is closer to 2 C, as you can see here:

    https://climatedataguide.ucar.edu/climate-data/global-surface-temperatures-best-berkeley-earth-surface-temperatures

    That’s ~14.5%, per the C-C relation.

    Looking forward, it gets worse: 3 C would be ~22.5%, and 4 C (God forbid) would be ~31%.

    As I say, that’s just a first-order point of departure; there’s more to precipitation, wildfire and drought than just Clausius-Clapeyron. But I hope it helps you to understand why the real topical ‘weeds’ are potentially well-worth getting into.

    2)

    …given the reasoning you’ve provided wouldn’t we expect to see more extreme effects in regions that are normally warmer than others (such as the tropics) and less extreme effects elsewhere, regardless of the global average? Is that the case?

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

    Funny thing about that:

    http://sitn.hms.harvard.edu/flash/2020/fire-on-ice-arctic-wildfires-are-the-new-symptom-of-a-warming-planet/

    Do I need to talk about Arctic phenology and, of course, sea ice loss, too? Just let me know, ’cause I can.

    But relating the discussion back at point #1 to the Arctic, the observed delta-T there *is*, in fact, about 4 C:

    https://nsidc.org/cryosphere/arctic-meteorology/climate_change.html

    So, the C-C effect there already amounts to about 31%, *today*. Not so surprising after all, perhaps, that the tundra is burning.

  10. 110

    Oops, meant to paste the link on Clausius-Capeyron:

    https://en.wikipedia.org/wiki/Clausius%E2%80%93Clapeyron_relation#Meteorology_and_climatology

    That also explains why C-C and “August–Roche–Magnus” are both required–and hence the apparently cryptic reference in my above comment.

  11. 111

    #101, Mack–

    You’re just wrong, Mack. And the empirical proof is that numerical weather forecasting works. It wouldn’t, if the physics E-P mentioned were incorrect.

    So, literally every weather forecast issued today (or, for that matter, issued over the last 40 years or so) bears tacit, practical witness to the physics. (And actually, the radiational physics was already taken into account long before the numerical forecasting era, even if it had to be dealt with via heuristic methods: “it has always been the case that a good treatment of radiative transfer is a prerequisite for reasonable near-surface temperature forecasts…”)

    https://www.ecmwf.int/sites/default/files/elibrary/2017/17771-radiation-numerical-weather-prediction.pdf

    Why? Note that temperature is a critical variable in Bjerknes’ “primitive equations” of atmospheric motion:

    https://en.wikipedia.org/wiki/Primitive_equations

    So the primitive equations can’t be used without getting temperature right, which depends in large part on getting the radiational warming/cooling right.

    That’s discussed here:

    https://history.aip.org/climate/pdf/Radmath.pdf

    That’s why Walter Elsasser (for one) worked so hard to arrive at usable approximations, starting in the mid-40s at CalTech. Here’s a published version of his tables, as published in 1960:

    https://link.springer.com/chapter/10.1007/978-1-940033-48-8_1

    But there were practical versions of this, intended for, and used in, operational weather forecasting.

    https://glossary.ametsoc.org/wiki/Elsasser%27s_radiation_chart (Other tables existed, too; Elsasser wasn’t the only one to investigate this.)

  12. 112
    William B Jackson says:

    #103 Victor If a given area is at 90 percent humidity at 75 degrees f and the temperature rises the relative humidity falls, now that air can take up more water vapor which it steals from the soil and the plants. The chances of fire increase. Why is this not obvious even to you?

  13. 113
    Al Bundy says:

    Woolhead,
    Sit a just-watered potted plant outside in the sun during a cool period. Log how much water you need to add per week to keep it from wilting.

    Now place the same size/type of plant on a table in the sun and water it to a schedule adjusted based on your increased rainfall map. So if rainfall intensity has increased you water the same number of times, but use more water, so it floods your table.

    You’ll find out that the plant dies, along with your flooded table.

    Basically, unless you increase the frequency of rain you haven’t done diddly by increasing the amount (other than to inflict flooding).

    So YOU tell us how this increase in flooding with NO increase in rainy days supports your kindergarten hypothesis.

    Or give us some evidence that the number of rainy days is increasing.

    Crops and other plants depend primarily on total TIME of rainfall, not total rainfall, which is why farmers love drizzle and hate global warming induced flash floods that carry away vital soil.

    You know, woolhead, SMART people look at evidence for clues about how they are WRONG. You look at evidence and toss all of it out except the bits that can be warped into “supporting” your elementary beliefs.

    You are NOT as bone-stupid as you insist on being. Seriously, you CAN improve your mind’s functioning, perhaps enough to contribute something useful. Yes, I’m being optimistic. My guess is that you are so intent on stupidifying yourself that it would be a waste of effort to try to rehabilitate your self-addled brain.

  14. 114
    Al Bundy says:

    Zebra: To say that Obama’s policies represented “lukewarmism” is beyond ridiculous. They represent pragmatism.

    AB: Not even close. Obama’s terms were approximately 50% giving GOPpers everything they desired to “show” that Obama was willing to compromise,
    and 50% whining that though he compromised the GOPpers never budged a nanometer.

    No, that’s wrong. The GOPpers did move. Miles and miles rightward towards fascism.

    Basically, Obama was a fool who engaged in one-sided compromise even when he controlled both houses of Congress.

  15. 115
    Al Bundy says:

    Susan A: I am a silly person

    AB: You are a breath of fresh air and your comments have taught me a bunch.

    In contrast, Killian screams insults while doing the Trumpian Dance. Trump has his non-existent healthcare plan and Killian has his non-existent climate plan that he constantly crows about but refuses to reveal to anyone who isn’t willing to send him a huge check in advance.

    Anyone here know anything solid about Killian’s “plan”? After a couple decades I’d think most folks would have a solid understanding of his Work – if there was anything there.

  16. 116
    Al Bundy says:

    Mack,

    Lots of folks misunderstand the “argument from authority” error.

    It does NOT suggest that a “C” student like you could even formulate a logical argument. It does NOT say that your ideas have the slightest validity.

    It says that, like in the movie, a janitor might be able to solve a problem a professor left as a challenge to his/her students.

    But unless you solve that challenge you ain’t in the game and your opinion is totally worthless.

  17. 117
    Victor says:

    re #103. Yes, nigel, yes, I’ve read articles like those you’ve linked to and am well aware of the argument that warm air sucks moisture out of the ground. In itself that argument makes sense. But I can’t help but notice that neither of these reports addresses the other side of the coin, i.e., the increased likelihood of extreme rainfall associated with the same cause: rising temperatures.

    One could of course assume that high temperatures in a dry environment would cause that environment to get even drier, but not necessarily result in rainfall if the moisture sucked from the environment isn’t sufficient to saturate the atmosphere. Whereas high temperatures in an already moist environment could suck up enough moisture to saturate the atmosphere and make rainfall more likely.

    But once again, it’s difficult to see how only a 1 degree increase in global temperature over a period of roughly 100 years could make such a huge difference in the likelihood of either fires, droughts or floods. And if differences in temperature matter so much then we would expect to find a pattern of more forest fires, droughts and floods in the warmer latitudes, no?

    Finally I could not help but notice the reference in the carbonbrief article to the fact that, globally, the area burned by wildfires each year is decreasing:

    “With climate change raising the risk of hot and dry weather in many parts of the world, it may seem prudent to assume that the global area burned by wildfires each year is increasing.

    However, several research papers looking into wildfires at a global level have come to the opposite conclusion. A paper published in the journal Science found that, globally, the area burned by wildfires decreased by 25% between 2003 and 2015.”

    While the authors attempt to explain away this embarrassing “paradox” it’s evidence that can’t simply be ignored. In short, I can see how a slight increase in temperature might tend to make dry areas drier and moist areas wetter, however I find it very hard indeed to associate such a trend with the sort of extreme effects being claimed, not only in the realm of fire, drought and flood, but also sea level, hurricanes, widespread species extinction, and now, as claimed by Stefan, a weakening of the Gulf Stream system.

  18. 118
    Western Hiker says:

    From #103

    “When temperatures are warmer than average, rates of evaporation increase, causing moisture to be drawn out from plants on the land. This drying can create “tinderbox conditions” – meaning that, if a fire is sparked, it can spread very quickly over large areas……”

    This is somewhat misleading. You could have a tinderbox forest, oversized fuel load and dry lightning; still, it won’t be a fast spreader without gusty winds. Climate change can help create the tinderbox, but in a given, individual event, windspeed is still the x- factor.

  19. 119

    Al @ 113 – WTF are you talking about? Not once has anyone mention “# of rainy days” as a parameter. Your completely dismissing my observation by assuming the rainfall in Australia 120 years ago was perfect, and any increase anywhere on the continent/island is lost as floods?

    My observation using the data on the linked display was that there was no correlation between change in precipitation and annual precipitation. i.e. dry areas are not getting drier and wet areas are not getting wetter

    Take for example Ray@85 “So dry gets drier, wet gets wetter.”

    Or nigelj@88 “And global warming increases atmospheric moisture so causes more intense rainfall events as well. This is not inconsistent with more droughts because its at different times and places.”

    or JB@91 “I think the idea is that in dry regions (mostly inland), warmer air is more effective at pulling water out of the soil – and, because it has a higher carrying capacity for water, is less likely to rain that moisture back out.”

    Or the absolute clanger BPL@92 ” Global warming, under the present continental configuration, moves the rain. Continental interiors dry out, coastlines get soaked. The contrast between dry areas and wet areas increases as the temperature rises.”

    These are what I am talking about, all these statements are rubbish and unsupported by data.

  20. 120
    Mack says:

    @111 Kevin McKinney
    @116 Al Bundy

    @105 BPL
    “Militant ignorance is ugly”

    “Intelligent” ignorance is ugly and dangerous. Sending me off to read some textbooks doesn’t impress me one jot.
    So, how’s it going with that atmosphere keeping all the oceans liquid, BPL? How’s it going trying to explain to me that the oceans would be frozen solid with a global average temperature of -18 deg C if it wasn’t for that atmospheric”greenhouse effect”? You agreed with that a day or two ago here..
    http://www.realclimate.org/index.php/archives/2020/09/new-studies-confirm-weakening-of-the-gulf-stream-circulation-amoc/#comment-777353
    You said…”Want the math ?”
    Well, yes, I think I’m prepared for you to hit me with the math. Go ahead, make my day.

  21. 121
    nigelj says:

    Victor @117

    “re #103. Yes, nigel, yes, I’ve read articles like those you’ve linked to and am well aware of the argument that warm air sucks moisture out of the ground. In itself that argument makes sense. But I can’t help but notice that neither of these reports addresses the other side of the coin, i.e., the increased likelihood of extreme rainfall associated with the same cause: rising temperatures……..”

    Global warming is increasing ‘absolute humidity’, the amount of water vapour more or less permanently in the atmosphere, and its this that leads to more rainfall expressed as heavier rainfall events (for various complicated reasons not germane to this discussion). Typically these are outside of the forest fire season or more in coastal locations and if they are inland during the fire season they may be so far apart as to have little damping effect on vegetation. A waming atmosphere will indeed dry out vegetation more, provided ‘relative’ humidity is below saturation point. The key word is relative humidity. As you would know RL fluctuates depending on the prevailing weather. Basically its two separate issues. And the empirical evidence shows forest fires are getting more intense and frequent due to climate change. The preceding information is just an explanation of why.

    “But once again, it’s difficult to see how only a 1 degree increase in global temperature over a period of roughly 100 years could make such a huge difference in the likelihood of either fires, droughts or floods….”

    Despite the fact that numerous people like BPL have explained this to you quite well time and time again. Basically one degree represents a lot of additional energy over long time periods, where the change from day to night is a more extreme temperature change but is very temporary.

    “And if differences in temperature matter so much then we would expect to find a pattern of more forest fires, droughts and floods in the warmer latitudes, no?”

    No we wouldnt expect that, because its the change in temperatures that counts (or energy in the system as Zebra points out) not the geographical location.”

    “Finally I could not help but notice the reference in the carbonbrief article to the fact that, globally, the area burned by wildfires each year is decreasing.”

    Did you bother to wonder why? I would hazard a vaguely educated guess it might be better forest management and fire fighting techniques and resourcing, and some large forests have been replaced with crop lands so theres less to burn. But this all comes at considerable expense, and with climate change the price gets higher and higher and eventually we may not be able to keep up and larger and larger areas will probably be burned.

  22. 122
    nigelj says:

    Victor @117

    “re #103. Yes, nigel, yes, I’ve read articles like those you’ve linked to and am well aware of the argument that warm air sucks moisture out of the ground. In itself that argument makes sense. But I can’t help but notice that neither of these reports addresses the other side of the coin, i.e., the increased likelihood of extreme rainfall associated with the same cause: rising temperatures……..”

    Global warming is increasing ‘absolute humidity’, the amount of water vapour more or less permanently in the atmosphere, and its this that leads to more rainfall expressed as heavier rainfall events (for various complicated reasons not germane to this discussion). Typically these are outside of the forest fire season or more in coastal locations and if they are inland during the fire season they may be so far apart as to have little damping effect on vegetation. A waming atmosphere will indeed dry out vegetation more, provided ‘relative’ humidity is below saturation point. The key word is relative humidity. As you would know RL fluctuates depending on the prevailing weather. Basically its two separate issues. And the empirical evidence shows forest fires are getting more intense and frequent due to climate change. The preceding information is just an explanation of why.

    “But once again, it’s difficult to see how only a 1 degree increase in global temperature over a period of roughly 100 years could make such a huge difference in the likelihood of either fires, droughts or floods….”

    Despite the fact that numerous people like BPL have explained this to you quite well time and time again.

    “And if differences in temperature matter so much then we would expect to find a pattern of more forest fires, droughts and floods in the warmer latitudes, no?”

    No we wouldn’t expect that, because its the change in temperatures that counts (or energy in the system as Zebra points out) not the geographical location.”

    “Finally I could not help but notice the reference in the carbonbrief article to the fact that, globally, the area burned by wildfires each year is decreasing.”

    Did you bother to wonder why? I would hazard a vaguely educated guess it might be better forest management and fire fighting techniques and resourcing, and some large forests have been replaced with crop lands so theres less to burn. But this all comes at considerable expense, and with climate change the price gets higher and higher and eventually we may not be able to keep up and larger and larger areas will probably be burned.

  23. 123
    nigelj says:

    Susan Anderson @93, I would echo AB’s comments. I enjoy your comments so dont be put off contributing by bad tempered people who make false allegations about you.

  24. 124
    Adam Lea says:

    Ray Ladbury@107:
    By “relatively drier”, do you mean the relative humidity of warmer air vs cooler air? If the air is warmed and the relative humidity stays the same, that will still lead to an increase in drying out of the landscape if the relative humidity is well below 100% (e.g. in anticyclonic conditions), because rate of evaporation increases with temperature, and as you say, the warmer air’s capacity for water vapor is higher, so more water can evaporate into each cubic meter of air.

  25. 125
    Killian says:

    116 Al Bundy says It says that, like in the movie, a janitor might be able to solve a problem a professor left as a challenge to his/her students.

    But unless you solve that challenge you ain’t in the game and your opinion is totally worthless.

    I’ve solved and predicted more than any other poster here. In fact, none of you have predicted nor solved… anything. Yet, the Peanut Gallery continues to be the Peanut Gallery, doing nothing, saying nothing, while others, like myself, present novel solutions to our problems.

    What shall we call your collective error? Suicide?

  26. 126
    Astringent says:

    Victor @117 remains personally incredulous, which is at least one point of stability in a changing world. He quotes a 1 degree rise in temperature when he has been reminded that, over land (which is where we get droughts and floods!), temperature rises are approaching 2 degrees. He ignores the fact that in many areas (because weather!) it’s not about every day everywhere being 2 degrees warmer, but an average. For some parts of the globe in some seasons warming will easily exceed an added 2 degrees. In his final paragraph he suggests (from personal incredulity again) that because the total area burnt has fallen over recent years (although Bolsonaro is doing his best to address that) there is some paradox. If I used his logic I would consider it a paradox if I went to the beach and got less sunburnt on the hotter sunnier day when I used sun-block than on a cooler day when I didn’t cover up.

  27. 127
    Killian says:

    115 Al Bundy says Susan A: I am a silly person

    AB: You are a breath of fresh air and your comments have taught me a bunch.

    In contrast, Killian screams insults while doing the Trumpian Dance. Trump has his non-existent healthcare plan and Killian has his non-existent climate plan that he constantly crows about but refuses to reveal to anyone who isn’t willing to send him a huge check in advance.

    Anyone here know anything solid about Killian’s “plan”? After a couple decades I’d think most folks would have a solid understanding of his Work – if there was anything there.

    God, the lying pieces of shit on this site…. Regenerative Governance has been outlined repeatedly on these pages.

    You can’t understand it, so it doesn’t exist?

    You’re disgusting.

  28. 128
    Adam Lea says:

    AB@115: “Anyone here know anything solid about Killian’s “plan”?”

    As I understand it, his plan advocates simplification of our lifestyles and a switch to sustainable living practices, where sustainable means consumption of resources has to be at a rate no higher than replenishment, and so theoretically can carry on indefinitely (absent any major shocks to the system). This is how the natural world (generally) operates in the absence of human activity; permaculture aims to observe how such systems in nature operate and find ways of mimicking them into our systems. Simplification does not mean going as far as living like hunter-gatherers in caves.

    What I haven’t seen is a step by step plan of how we get from where we are now to this sustainable simplified way of living, in a way that can be implemented globally fast enough to avert the worst potential impacts of climate change and lack of sustainability, and in a way that the majority of the global population will accept. He might have posted it somewhere on this blog or on his website but I haven’t seen it. It will involve throwing away capitalism, and the current Western economic models where financial cost is the ultimate dictator, since the big problem we have at the moment is the cheapest ways of doing things are frequently those with the larger externalised costs, and current economic models don’t care about externalised costs, if anything they encourage them.

  29. 129
    Killian says:

    93 Susan Anderson says @Killian – Despite your insistence, none of my comments until this most recent were addressed to you or about you. Your hostility does nobody any favors; I recommend getting a life instead of picking endless fights with people you don’t know based on misrepresentations, in extended monologues. Hatred is a distorting destructive toxin.

    Hatred? I don’t know you. Hate? You think you are worth that much energy? Think again.

    You don’t remember being an ass, so it didn’t happen? OK…

    I didn’t pick a fight, gaslighter, you did. More than once. And here you do it again when confronted with the facts of your past behavior.

    So, Susan, let’s suppose Regenerative Governance is the only option left. For argument’s sake – and because it is. You are rejecting it because you reject me, and we should consider anything you have to say given that suicidal choice? Show us you can think rather than just write words that make sentences.

    And try, as I encouraged you, to get past the bullshit and get to the substance, but, as always, you could not. But I’m the problem? Got it…

    Time’s short. Grow TF up.

    I read the Jahren books, and your eagerness to misrepresent her

    Are you for REAL? I have a SON. WHY THE FUCK WOULD YOU THINK I’M PLAYING FUCKING STUPID GAMES HERE? Disgusting.

    I have no “eagerness but to find truly sustainable actions being taken. Read whatever the fuck you want, but it won’t matter because YOU don’t understand what regenerative is. Get it? If you want a serious discussion, let’s start with defining in detail what regenerative fka sustainable is. You want real? Let’s get real. But you won’t like the end result because your thinking will have to change significantly.

    is only exceeded by your insistence that I’ve been bullying you.

    So, you don’t remember being as ass, so you weren’t. Got it.

    Don’t read the only person here suggesting systemic solutions. Brilliant.

    The world is full of, and run by, fools.

  30. 130

    M 106: More energy than what amount of energy? More energy since when? What’s the nature of the “more energy”…. linear, logarithmic, what? No numbers provided… just speculative, hand-waving tripe….

    BPL: Mack, math is your friend. Heat content is

    H = m cP T

    where H is heat content in joules, m mass in kilograms, cP specific heat at constant pressure in joules per kilogram per kelvin, and T absolute temperature in kelvins. The atmosphere has a mass of 5.148 x 10^18 kg and cP = 1006 J kg^-1 K^-1. Seawater has a density of 1,025 kg m^-3 and cP = 3,890 J kg^-1 K^-1; pick a good representative depth for the climate system of perhaps 70 meters. Rock has a density around 3,000 kg m^-3 and cP = 800 J kg^-1 K^-1, pick a shallower depth since heat penetrates solid ground much more slowly.

    Do the math. Mean global annual surface temperature is up 1.1 K or so since 1850.

  31. 131

    V 118: it’s difficult to see how only a 1 degree increase in global temperature over a period of roughly 100 years could make such a huge difference in the likelihood of either fires, droughts or floods.

    BPL: Asked and answered. Your argument from incredulity is getting annoying.

  32. 132

    Victor, #117–

    But once again, it’s difficult to see how only a 1 degree increase in global temperature over a period of roughly 100 years could make such a huge difference…

    Incredulity is not an argument nor an indicator, unless the incredulous person thoroughly understands the parameters and interactions in play. Which you have demonstrated you don’t, in this matter.

    I’m guessing you haven’t had time to read my answer to your argument from incredulity yet. (And I’m hoping for some more in-depth comment on rainfall and temps from others). But what I said is here. I hope it helps.

  33. 133
    mike says:

    A conversational exchange that simply ignores the trolls and refrains from flaming would be a wonderful thing.

    I am with AB at 115, even when I think she is wrong, SA is civil, thoughtful and occasionally silly. That works for me.

    There are a host of others here who post intelligently: KM, RL et al, and who are also too smart generally to get sucked into the role of troll-feeder.

    If I was to respond in any way to V and his sort, I would just say, ignore their provocative nonsense. And really, that’s not a response to the trolls, it’s a suggestion for those here who post in good faith.

    We have some real problems with global warming that warrant discussion and maybe even action. We are looking at warming ramping up, we are in a very hot year per the record, probably number 2, and that is happening absent an EN bump. The result is stuff like the fires in California and more. The next EN year is going to be a real doozy. It will not be fun. You can take that to the bank.

    Here is a measure that tells you how we are doing at addressing the problem of greenhouse gas accumulation:

    Last Week September 20 – 26, 2020 411.00 ppm
    1 Year Ago September 20 – 26, 2019 408.34 ppm
    10 Years Ago September 20 – 26, 2010 386.81 ppm

    Over a ten year period we observe a jump that averages ~2.42 ppm
    Over the last year, we observe a jump of 2.66 ppm.

    If ghg buildup was caused by an intelligent species, I think we would not see this kind of relentless increase in the accumulation, but maybe I am wrong, maybe we are intelligent and simply, woefully slow to act.

    I sometimes talk about that, but less and less, as I have aged out of the struggle to some extent.

    Warm regards,

    Mike

  34. 134
    Victor says:

    re Kevin @109:

    V: …given the reasoning you’ve provided wouldn’t we expect to see more extreme effects in regions that are normally warmer than others (such as the tropics) and less extreme effects elsewhere, regardless of the global average? Is that the case?

    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 . . .

    http://amoleintheground.blogspot.com/2019/05/thoughts-on-climate-change-part-9-even.html

    Now now folks. Don’t shoot the messenger. I’m not the expert. The “scientists” are.

    Regardless of how much temperature seems to have changed in the Arctic (or anywhere else), what we’re talking about here is how ever warmer atmospheric temperatures produce ever more extreme weather-related events, such as forest fires, droughts and extreme rainfall. So regardless of whether or not the Arctic is currently warming faster than anywhere else, historically its temperatures have been considerably lower than those in the lower latitudes. By the same token, the historical record, as we might expect, tells us that temperatures are, on average, much warmer in the lower latitudes than the higher ones. 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?

  35. 135
    nigelj says:

    The following is very comprehensive commentary on the impact of climate change on forest fires. It was written by Daniel Bailey over at skepticalscience com, responding to JoeZ. He’s ok with reposting it. It happens to back up a couple of points I made, and may be of general interest to people:

    “JoeZ, increased forest fire activity across the western U.S. in recent decades is due to a number of factors, including a history of fire suppression and human encroachment in forest regions, natural climate variability, and human-caused climate change. Forest management would help in some areas, however the wildfire numbers and burned area are also increasing in non-forest vegetation types. Wildfire activity appears strongly associated with warming temperatures (California spring/summer temperatures have increased by more than 5 degrees Fahrenheit since 1970) and earlier spring snowmelt.

    Source: NASA

    “For all ecoregions combined, the number of large fires increased at a rate of seven fires per year, while total fire area increased at a rate of 355 km2 per year. Continuing changes in climate, invasive species, and consequences of past fire management, added to the impacts of larger, more frequent fires, will drive further disruptions to fire regimes of the western U.S. and other fire-prone regions of the world.”

    https://agupubs.onlinelibrary.wiley.com/doi/full/10.1002/2014GL059576

    Since the 1980s, the wildfire season has lengthened across a quarter of the world’s vegetated surface.

    “We show that fire weather seasons have lengthened across 29.6 million km2 (25.3%) of the Earth’s vegetated surface, resulting in an 18.7% increase in global mean fire weather season length. We also show a doubling (108.1% increase) of global burnable area affected by long fire weather seasons (>1.0 σ above the historical mean) and an increased global frequency of long fire weather seasons across 62.4 million km2 (53.4%) during the second half of the study period.”

    https://www.nature.com/articles/ncomms8537

    “The start of the Southwestern fire season—as indicated by the date of first large-fire discovery—has shifted more than 50 days earlier since the 1970s, accounting for about one-third of the increase in the length of the fire season. The substantially earlier SW fire season start is consistent with warmer temperatures and earlier spring seasons leading to earlier flammability of fuels in SW forests.”

    https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4874415/

    “Anthropogenic increases in temperature and vapor pressure deficit significantly enhanced fuel aridity across western US forests over the past several decades and, during 2000–2015, contributed to 75% more forested area experiencing high (>1 σ) fire-season fuel aridity and an average of nine additional days per year of high fire potential.

    Anthropogenic climate change accounted for ∼55% of observed increases in fuel aridity from 1979 to 2015 across western US forests, highlighting both anthropogenic climate change and natural climate variability as important contributors to increased wildfire potential in recent decades.

    We estimate that human-caused climate change contributed to an additional 4.2 million ha of forest fire area during 1984–2015, nearly doubling the forest fire area expected in its absence.

    Natural climate variability will continue to alternate between modulating and compounding anthropogenic increases in fuel aridity, but anthropogenic climate change has emerged as a driver of increased forest fire activity and should continue to do so while fuels are not limiting.”

    https://www.pnas.org/content/113/42/11770

    “By 2100, if greenhouse gas emissions continue to rise, one study found that the frequency of extreme wildfires would increase, and the average area burned statewide would increase by 77 percent. In the areas that have the highest fire risk, wildfire insurance is estimated to see costs rise by 18 percent by 2055. ”

    https://climateassessment.ca.gov/state/overview/#wildfire

    “The clearest link between California wildfire and anthropogenic climate change thus far has been via warming-driven increases in atmospheric aridity, which works to dry fuels and promote summer forest fire, particularly in the North Coast and Sierra Nevada regions.

    Importantly, the effects of anthropogenic warming on California wildfire thus far have arisen from what may someday be viewed as a relatively small amount of warming. According to climate models, anthropogenic warming since the late 1800s has increased the atmospheric vapor-pressure deficit by approximately 10% and this increase is projected to double by the 2060s. Given the exponential response of California burned area to aridity, the influence of anthropogenic warming on wildfire activity over the next few decades will likely be larger than the observed influence thus far where fuel abundance is not limiting.

    Since the early 1970s, California’s annual wildfire extent increased fivefold, punctuated by extremely large and destructive wildfires in 2017 and 2018. This trend was mainly due to an eightfold increase in summertime forest‐fire area and was very likely driven by drying of fuels promoted by human‐induced warming. Warming effects were also apparent in the fall by enhancing the odds that fuels are dry when strong fall wind events occur.

    The large increase in California’s annual forest-fire area over the past several decades is very likely linked to anthropogenic warming.

    Human‐caused warming has already significantly enhanced wildfire activity in California, particularly in the forests of the Sierra Nevada and North Coast, and will likely continue to do so in the coming decades.”

    https://agupubs.onlinelibrary.wiley.com/doi/abs/10.1029/2019EF001210

    Wildfire mitigation efforts can reduce wildfire intensity and severity while improving forest resilience to fire, insects and drought. The total area burned by wildfires is a trend driven by the warming climate (which is warming because of human activities), so mitigation efforts will not likely be able to affect the total area burned trend.

    https://link.springer.com/article/10.1186/s42408-019-0062-8

    Droughts in the Southwestern US have been made nearly half-again worse by human activities and are projected to worsen yet.

    https://science.sciencemag.org/content/368/6488/314

    These droughts couple with rising temperatures, reduced soil moisture and lower humidity to kill vast amounts of trees, providing an ever-increasing amount of fuel loads for wildfires.

    https://science.sciencemag.org/content/368/6488/238

    California’s frequency of fall days with extreme fire-weather conditions has more than doubled since the 1980s. Continued climate change will further amplify the number of days with extreme fire weather by the end of this century.

    https://iopscience.iop.org/article/10.1088/1748-9326/ab83a7

    California Fires

    https://twitter.com/CAL_FIRE/status/1311722710284693505

    There is strengthened evidence that climate change increases the frequency and/or severity of fire weather around the world. Land management alone cannot explain recent increases in wildfires.

    Analysis shows that:

    • Well over 100 studies published since 2013 show strong consensus that climate change promotes the weather conditions on which wildfires depend, enhancing their likelihood.

    • Natural variability is superimposed on the increasingly warm and dry background conditions resulting from climate change, leading to more extreme fires and more extreme fire seasons.

    • Land management can enhance or compound climate-driven changes in wildfire risk, either through fuel reductions or fuel accumulation as unintended by-product of fire suppression. Fire suppression efforts are made more difficult by climate change.

    • There is an unequivocal and pervasive role of climate change in increasing the intensity and length in which fire weather occurs; land management is likely to have contributed too, but does not alone account for recent increases in wildfire extent and severity in the western US and in southeast Australia.

    Human-induced climate change promotes the conditions on which wildfires depend, enhancing their likelihood and challenging suppression efforts. Although the global area burned by fires each year is declining, the majority of this trend is explained by conversion of natural savannahs and grasslands to agriculture in Africa (Andela et al. 2017). In contrast, the area burned by forest wildfires is increasing in many regions, including in the western US and southeast Australia.

    • “Fire weather” refers to periods with a high likelihood of fire due to a combination of high temperatures, low humidity, low rainfall and often high winds.

    • Human-induced warming has already led to a global increase in the frequency and severity of fire weather, increasing the risks of wildfire.

    • Land management can ameliorate or compound climate-driven changes in wildfire risk.

    • Wildfires can have broad impacts for human health and wellbeing and for the natural environment.

    US fires:

    • Fire weather has become more frequent and intense in western US forests.

    • Fire weather is driving more wildfire activity in western US forests.

    • Demographic factors alone cannot account for the magnitude of the observed increase in wildfires in the western US, but increased population leads to greater impacts.

    • Land management practices are contributing factors, but cannot alone explain the magnitude of the observed increase in wildfires extent in the western US forests in recent decades.

    Australia fires:

    • The scale of the 2019–2020 bushfires was unprecedented.

    • Fuel management through prescribed burns and improved logging practice cannot fully mitigate increased wildfire risk due to climate change.

    • Extreme weather and Pyroconvection are projected to increase wildfire risk under future climate change in southeastern Australia.

    Scientific evidence that climate change is causing an increase in the frequency and extent of fire weather, contributing to extreme wildfires around the world, continues to mount.

    The severe droughts in the USA and Australia are signs that the tropics, and their warm temperatures, are expanding in the wake of climate change, due to the warming of the subtropical ocean.

    https://public.wmo.int/en/media/news/climate-change-increases-risk-of-wildfires
    https://sciencebrief.org/topics/climate-change-science/wildfires
    https://sciencebrief.org/briefs/wildfires
    https://news.sciencebrief.org/wildfires-sep2020-update/
    PDF here

    Climate change will continue to drive temperature rise and more unpredictable rainfall in many parts of the world, meaning that the number of days with “fire weather” – conditions in which fires are likely to burn – is expected to increase in coming decades.

    Carbon Brief Wildfire explainer

  36. 136
    Mack says:

    @130 BPL
    Wow, yes, I see from one of your previous comments you said something like 13.68 trillion Hiroshima Bombs was going (mainly) into the oceans from all that extra energy from all those “greenhouse” gases we’ve put into the ATMOSPHERE. How it got from the atmosphere and into the oceans remains a mystery… you know, if I use a hot air dryer over a bath of water,it doesn’t seem like Hiroshima bombs worth of heat develops in the bath water. But it must be true, because, looky here, Skeptical Science says it’s true…with their widget.
    https://4hiroshimas.info/ 4 Hiroshima bombs/sec worth of heat going into the oceans.
    “This warming is due to more heat trapping gases in the atmosphere” … they say. Wow! that is some “heat trapping”. 4 Hiroshima bombs/sec.!! I don’t know if the next time I go for a dip in the sea, whether I’ll be cooked in the water or irradiated from the atmosphere.

    But this math you’ve given me is a deflection isn’t it, BPL.? The math you are supposed to come up with is the math that explains why you say the oceans are frozen solid with a global average temperature of -18 deg C if it wasn’t for the atmospheric “greenhouse effect”.
    It also ties in with your opinion that the Earth could be flat, BPL.?

  37. 137

    Victor, #134–

    OK, that was a comment.

    Two points.

    1) 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?

    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.

    One reference of many:

    https://data.giss.nasa.gov/gistemp/maps/index_v4.html

    2) 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.

    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.

    Consider the first graph at this link:

    https://www.researchgate.net/figure/a-Zonal-mean-precipitation-and-b-surface-latent-heat-fluxes-corresponding-to-Fig-1_fig6_305783306

    It shows clearly that rainfall is dependent (in part) upon latitude; whereas precipitation peaks between 5-13 mm/day at roughly 10N, poleward of 80 degrees one may expect considerably less than 1mm/day. 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.

    A similar dynamic applies to temperature, of course; in fact, headlines were made on a global scale this past summer when Siberia experienced for the first time temperatures unremarkable in the tropics and subtropics. It’s worth noting here that the term “extreme” is merited in a practical as well as technical sense, because with hot extremes in the far North we also see drastic increases in wildfire, including on the tundra; melting of permafrost soils, leading to topographic change (and, for human structures, foundation failure); and of course enhanced seasonal or permanent loss of ice and snow cover.

    Second, remember that “extreme” is time-dependent as well: “specific conditions at a particular place and time.

    For example, most places have fairly marked seasonal changes in precipitation or temperature or both. But, since we are talking about climate change here, time-dependence is important to keep in mind over the longer term as well. For example, where I live, we are roughly two ‘hardiness zones’ warmer than in 1970 or so (if I’m recalling the baseline date correctly, which I may not be.)

    I raise this because I suspect Victor is not keeping this clearly in mind. Consider this sentence:

    Regardless of how much temperature seems to have changed in the Arctic (or anywhere else), what we’re talking about here is how ever warmer atmospheric temperatures produce ever more extreme weather-related events, such as forest fires, droughts and extreme rainfall.

    To my mind, if we’re talking about “ever warmer atmospheric temperatures” then we cannot at the same time be talking “[r]egardless of how much temperature seems to have changed in the Arctic (or anywhere else).” The sentence is self-contradictory. Victor may wish the conversation were about “climate”, but it remains resolutely about “climate change.”

    Third, we must note that, nevertheless, some types of extreme weather events are (or were) exclusive to, or at least characteristic of, one latitude or another.

    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.

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

    It used to be rare, but now is rather less so.

  38. 138
    Adam Lea says:

    133: “If ghg buildup was caused by an intelligent species, I think we would not see this kind of relentless increase in the accumulation, but maybe I am wrong, maybe we are intelligent and simply, woefully slow to act.”

    We are an intelligent species but are hardwired with primitive instincts and cognitive biases that worked well when we lived very simply, but are terrible in dealing with issues in the modern world. Humans are a bit like androids with a core program full of bugs.

  39. 139
    jb says:

    Wool*ard at 100, 119:”My observation using the data on the linked display was that there was no correlation between change in precipitation and annual precipitation. i.e. dry areas are not getting drier and wet areas are not getting wetter”

    “Dryness” is not about precipitation – which is the data you showed us. It is about the difference between precipitation and evaporation. Since you don’t believe in theory, you don’t even know what data to use.

    The only rubbish around here is your approach to “data analysis.”

  40. 140

    Not to try to direct things off-topic, but is anyone planning to post a new “Forced Responses” thread this month?

  41. 141
    Victor says:

    re #135

    “Charcoal layers in sediments and methane concentration in ice cores show that the amount of global burning can fluctuate dramatically over time. The charcoal records, derived from lake sediments and peats at hundreds of sites around the world, show a distinct lull in burning from about 1600 to 1750 that leads into an unprecedented surge in fires beginning around 1800. Then, around 1900, global fire occurrence begins a rapid decline that continues until the present.” https://www.nasa.gov/topics/earth/features/fiery-past.html

    As for drought:

    https://media.springernature.com/full/springer-static/image/art%3A10.1038%2Fsdata.2014.1/MediaObjects/41597_2014_Article_BFsdata20141_Fig5_HTML.jpg?as=webp

    source: https://www.nature.com/articles/sdata20141#Fig5

  42. 142
    Ray Ladbury says:

    Adam Lea@124, Relative humidity is a big part of it, but as you intimate, the general climatic patterns also play a role, leading to regions with generally higher and lower RH. And of course, air moves, and in so doing produces regions of high precipitation on the windward side of the mountains, and a rain shadow on the leeward side.

    As to Weaktor’s query about tropical vs. temperate zones–shouldn’t the names give him a clue? And then there is the average energy in a tropical storm vs. a Noreaster.

  43. 143
    nigelj says:

    Adam Lea @128

    Regarding your understanding of Killians ‘plan’ and its difficulties. Paraphrasing your post, it means simplifying living, and living within the limits of the biosphere, and you haven’t seen a plan of how we could do everything fast enough to deal with climate change.

    I agree with all of what you say. Its my reaction exactly.

    There is more to his plan, including a transition to shared ownership of the means of production and resource base, and egalitarian governence (eliminating hierarchies) substituting renewable resources like timber, for non renewables (like metals and oil), and eliminating waste, building only minimal solar and wind power, and making massive 80 – 90% reductions in use of mineral resources and energy (of any sort) and very frugal use of modern technology limited to the basic essentials, and wide adoption of passive solar buildings.

    The plan has some positive attributes, but there are multiple obvious problems with such a plan, and I have described them before and again its hard to see how it could happen rapidly enough to deal adequately with climate change. As have others.

    I think a more viable plan is to concentrate on big reductions in waste (using the term widely to include landfill waste, pollution, eliminating burning fossil fuels, and reducing extravagant consumption, and not wasting energy) and zero population growth, and scaling up renewable energy. This is simple to grasp, doable and reasonably acceptable to the public, and is already happening under Capitalism in some places, or it may ultimately lead to a new socio economic system.

    But you have to start with a goal of reducing waste and building renewable energy, not trying to rebuild the entirety of human civilisation both physically and its socio economic systems virtually from the ground up in the next 10 years or so. Because that’s just not really possible, its a much longer term thing.

  44. 144
    nigelj says:

    Killian @129,

    “I didn’t pick a fight, gaslighter, you (Susan Anderson) did. More than once.”

    I do not recall Susan Anderson responding to any of your posts, or referring to you in person before this page. I don’t see any proof from you that she has, like a copy and paste with a date and time and a link back.

    You accuse her of having a bad memory. Are you sure you haven’t mixed her up with someone else? Do you think its possible you might have a bad memory yourself?

    The only thing I can recall is she once complained about name calling, although she wasn’t specific who. And she has every right to complain about that, and to suggest she is picking a fight because of that is ridiculous.

    “And here you do it again when confronted with the facts of your past behavior.”

    I don’t see her picking a fight with you on this particular page, or saying anything nasty about you or your ideas. The first exchange on this page between you two was initiated by YOU @48. In it you say she has seen your comments here on reducing consumption for years but didn’t give you “a shout out”. How on earth would you know what comments she has seen. She has only posted a small number of comments and may well have read none or very few of your comments.

    And I’ve read dozens of people preach reducing consumption, going right back to the 1970s, and I think we should aim to do that myself. What makes you so special?

    She acknowledged various other points you made.

    Her response to you @60 was a model of politeness, and I don’t see her “picking fights” with you or bullying you or being nasty in that response or any other .

    I don’t even see her criticising your ideas, as I admit I have done.

    She feels you misrepresented the contents of some book. That is the only real criticism I can find. Its hardly picking a fight. You constantly complain that people misrepresent you.

    She says you come across as angry and hostile. Well that’s simply stating a fact.

    Even if she had said something derogatory, how does that make it ok for you accusing her of acting like an “ass”? Have you not heard of the old saying two wrongs dont make a right?

    It looks far more like you want to pick a fight with Susan Anderson, given your extended angry hostile rants and vile language. Get a fucking grip on yourself. The rest of us make the effort.

  45. 145
    Richard Creager says:

    Killian, 127, 129 etc etc- Regenerative ag, permaculture, drastic simplification are promising principles to organize a sustainable society around. They are not a plan to get from our current to a sustainable world. But difficulties, obstacles, hindrances disappear to the hypomanic, commenters become belittlers to be execrated. Your online behavior is insupportable. If we all acknowledge that you first proposed slicing bread and invented the smartphone, and all type your name in boldface italics, will you stop. Please.

  46. 146
    nigelj says:

    This regenerative governenance concept Killian talks about above and elsewhere appears to be shared ownership of the resource base and means of production combined with shared decision making, (so you have no hierarchies of decision making). I have never seen a proper definition of the term regenerative governance, so I have to decipher bits and pieces of commentary to draw this conclusion. The concept is touted as being an essential part of sustainability and and resolving the climate problem.

    Modern alternative lifestyle communities (intentional communities) have been experimenting with shared ownership and shared governance ever since the counter culture revolution of the 1960’s. Some of these groups also have environmental and self sufficiency goals that Killian and others advocates. A simple google search shows most of these communities fail quite quickly. The reasons appear to be disputes and in fighting, or the groups devolve into drug taking and sex abuse and run foul of the law. And state lead mass experiments in shared ownership like the old USSR didn’t work very well.

    The trend in modern society in the last few decades has been towards private ownership. I have nothing against some state ownership of essential services, but when such ownership intrudes on industry and agriculture the results have not been compelling.

    I have nothing against these alternative lifestyle groups and I admire the experimentation, but the results just don’t seem compelling, sad to say. The concept has only ever attracted a small minority of the population. The small number that have endured longer term appear to be religious based or they have very passionate supporters, or don’t quite fit Killians model. Maybe Killian has a alternative lifestyle model that will break the dismal trend of failures but its hard to say without seeing a coherent detailed description.

    The point is it looks like its not been possible to scale the whole shared ownership and shared governance model up. If it hasnt scaled up by now, I’m not confident it ever will be. Am I being too pessimistic?

  47. 147

    M 136: How it got from the atmosphere and into the oceans remains a mystery…

    BPL: Infrared radiation, Mack. Again, I urge that you read a book on atmosphere physics and work the problems. I can recommend some good ones.

  48. 148
    Mack says:

    @ 147 BPL

    Well, I must say I’m very disappointed with you ,BPL.
    I just get… “infrared radiation”….. no math…. even though you said you’d give me “the math” @38. There was no desire to find out what the mistake might be that causes you to believe that the ATMOSPHERE prevents the oceans from being frozen solid at -18deg C.
    I can understand that. There’s a little nagging thought that maybe the whole thing IS as wacko as it sounds. It might mean that all those books you’ve written should be just biffed in the waste basket.
    Never mind… carry on.

  49. 149
    Mack says:

    Sorry @147 BPL again,

    My curiosity about you BPL, has grown a bit and you certainly have put yourself out there…..You’ve got your own Wiki page…
    https://en.wikipedia.org/wiki/Barton_Paul_Levenson
    Now I see you’re a science fiction writer. Those books you should treasure,BPL. It’s the peer-reviewed scientific articles since 2011 that you should biff in the rubbish bin.
    Actually, you’re quite inspirational to me… I’m thinking of writing a REAL science book myself.. the title….”It’s The Sun, Stupid”. What say you and I get together and write this book. I’ve even thought out the book cover picture. It’s that NASA picture of the little blue orb of the Earth, to one side, with the giant blazing Sun behind. (Thank God for circular motion) It’s pretty obvious from that picture, WATER is what determines Earth temperature… CO2 doesn’t get a look in.

  50. 150
    Susan Anderson says:

    Please don’t escalate (friend or “foe” (and as to “foe” I’m not insofar as I understand very well that we’re all in trouble and our efforts to address it, all but a few, are pathetic)). I don’t comment here very often, mostly because I’m not a scientist, but also because sometimes the protracted arguments make one want to go elsewhere.

    I appreciate the work of RealClimate’s hardworking authors, but my lack of relevant expertise and wandering attention, including anything on my mind that, however, loosely, relates to the topic, are why I often don’t venture to post here.

    Jahren’s hard-won suggestion to “use less and share more” – the meat of my mention – and refs to The Story of Stuff, and (I left this out) the circular economy are about solutions. The site below has been updated to focus more on getting involved. They are pushing about plastic now (imnsho, good idea)

    We have a problem with Stuff: we have too much of it, too much of it is toxic, and we don’t share it very well. But that’s not the way things have to be.

    https://www.storyofstuff.org/about

    As to topic, I’d recommend that this thread be kept to anything that is remotely relevant. As for me, time to move to “Unforced Variations”.

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