Revisiting the global hydrological cycle: is it intensifying?

Demetris Koutsoyiannis

Department of Water Resources and Environmental Engineering, School of Civil Engineering, National Technical University of Athens, Heroon Polytechneiou 5, GR 157 80 Zografou, Greece

Received: 11 Mar 2020 – Discussion started: 20 Mar 2020 – Revised: 31 May 2020 – Accepted: 30 Jun 2020 – Published: 07 Aug 2020

Abstract. As a result of technological advances in monitoring atmosphere, hydrosphere, cryosphere and biosphere, as well as in data management and processing, several databases have become freely available. These can be exploited in revisiting the global hydrological cycle with the aim, on the one hand, to better quantify it and, on the other hand, to test the established climatological hypotheses according to which the hydrological cycle should be intensifying because of global warming.

By processing the information from gridded ground observations, satellite data and reanalyses, it turns out that the established hypotheses are not confirmed. Instead of monotonic trends, there appear fluctuations from intensification to deintensification, and vice versa, with deintensification prevailing in the 21st century. The water balance on land and in the sea appears to be lower than the standard figures of literature, but with greater variability on climatic timescales, which is in accordance with Hurst–Kolmogorov stochastic dynamics.

The most obvious anthropogenic signal in the hydrological cycle appears to be the over-exploitation of groundwater, which has a visible effect on the rise in sea level. Melting of glaciers has an equal effect, but in this case it is not known which part is anthropogenic, as studies on polar regions attribute mass loss mostly to ice dynamics.

How to cite: Koutsoyiannis, D.: Revisiting the global hydrological cycle: is it intensifying?, Hydrol. Earth Syst. Sci., 24, 3899–3932, https://doi.org/10.5194/hess-24-3899-2020, 2020.

From the Concluding remarks.

The most obvious anthropogenic signal in the hydrological cycle is the over exploitation of groundwater, which has a visible effect on the rise in sea level. Melting of glaciers has an equal effect, but in this case it is not known which part is anthropogenic as studies of polar regions attribute mass loss mostly to ice dynamics.

The above observations strengthen an earlier (Koutsoyian- nis et al., 2009) envisagement of the hydrological community’s role. Instead of a passive role in assessing hypothetical hydrological impacts based on doubtful climate model outputs, an active role consistent with its history is possible.

Indeed, hydrology has much more to offer to societies than prophesies of future catastrophes (cf. Koutsoyiannis, 2020a). During the 20th century, and particularly after the Second World War, hydrology, by supporting hydrotechnology, water management and risk assessment and reduction, within a strong international collaboration and a strong economy, has substantially contributed to human life as a value and to the quality and length of human life

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37 thoughts on “Revisiting the global hydrological cycle: is it intensifying?

  1. The “global hydrological cycle” is mostly a myth, other than the fact that in periods of warming there is more moisture available, and in cooling periods there is less. Within that though, there are huge variations in different regions, with some more prone to drought, and others to flooding. Of course, the Climate Alarmists like to claim that the climate is now “confused”, producing both more floods and droughts, and that we are now experiencing “extreme” weather (laughably wrong).

    • Bruce, its all science in the Postmodern Age. The alarmists think that the Climate is experiencing an identity crises and it is all mans fault. Now i might consider that It is just possible, the climate has Hydrological Disphoria it was born wet but believes it is dry. Either way there is a whole lot of social sciencing going on to explain the inexpiable and make it punishable by twitter to disagree with the new world order.

    • On the face of it, I would agree with your comment “that in periods of warming there is more moisture available, and in cooling periods there is less.” As most of the warming since the end of the LIA is natural variation, especially to at least the early 1950’s before CO2 could have had any significant effect, any increase in the general hydrological water cycle is also natural variation. It would be common sense to assume that a warmer climate will have more atmospheric moisture available.

      How that delivers more water to any specific region on the good Earth needs a lot of truthful data collection, so as we can start to tabulate what, where, how etc, the additional water vapor manifests itself. Common sense would also say that having more atmospheric water available would be net beneficial. Having said that, more rain in a flood plain is obviously going to cause flooding, but then it is a flood plain, and expected that there would be periodic flooding. Especially if half the flood plain is paved over. Which is where a lot of the reported flooding is happening.

    • Quote: The “global hydrological cycle” is mostly a myth, other than the fact that in periods of warming there is more moisture available, and in cooling periods there is less“
      Not true Bruce. The Hydro Cycle and is very real, it operates thermodynamically as a Rankine Cycle, which few people appreciate. In the Rankine cycle variations in heat input result in a change in the RATE of the cycle; but NOT the MASS of the working fluid involved. This fact is demonstrated daily in our steam generating plants which operate at constant temperature and pressure in a CLOSED system irrespective of the variations of heat input.
      Hence we do not see changes in the atmospheric moisture content responding to purported energy input as claimed by the GHE. We may, however find that precipitation occurs more frequently; but the quantity will remain the same.
      Otherwise I go along with the rest of your comment. Cheers!

    • I have a problem with using the words ‘warming’ and ‘cooling’ as they disregard enthalpy. So humid air at 75F has more heat energy (Kilojoules per kilogram) than dry air at 100F. So the hydrologic cycle can ‘warm’ and ‘cool’ air too in that the temperature (an intensive variable) is dependent on both humidity and heat energy. Indeed, a small change in atmospheric humidity could account for the entire 2C change in temperatures by varying average atmospheric enthalpy.

      If the ‘global warming’ hypothesis is based on ‘trapping heat energy’ then that is what should be measured. The units are kilojoules per kilogram. After all the green house effect does not ‘trap temperature’.

      It seems that an HVAC engineer knows more about enthalpy than climate ‘scientists’.

      • Enthalpy is a difficult concept, even for most chemists/ physicists, etc. It has caused more than its fair share of wrong answers on tests in college, that’s for sure.

  2. My local college has a PHD hydrologist as an instructor. She is totally political and unscientific.
    She openly states that her studies are done to achieve political objectives.

    • Pass her along a copy of my paper, Billy.

      It’s open access, strongly peer-reviewed, is correct, and it shows that the IPCC don’t know what they’re talking about.

      It will also nullify all your hydrologist professor’s career goals, unless she re-focuses on actual science.

  3. “it turns out that the established hypotheses are not confirmed. Instead of monotonic trends, there appear fluctuations from intensification to deintensification, and vice versa, with deintensification prevailing in the 21st century.”

    Now isn’t that curious? I wonder if this is related to the ideas of Ferenc Miskolczi that the atmospheric thermal radiant opacity is a fixed and mathematically predictable constant, such that as the quantity of carbon dioxide increases in the atmosphere the quantity of water vapour drops.

    • Philip – a slight refinement

      The water vapour drops at particular altitudes. The effect of water vapour reverses according to altitude. Ferenc has it that the total column remains essentially constant, with the proviso that whether there should be warming or cooling will place water vapour where it produces the needed effect to balance the system.

  4. “The most obvious anthropogenic signal in the hydrological cycle is the over exploitation of groundwater, which has a visible effect on the rise in sea level. Melting of glaciers has an equal effect, but in this case it is not known which part is anthropogenic as studies of polar regions attribute mass loss mostly to ice dynamics.”

    Contrary to some of the above comments, this does not seem to be a politically inspired conclusion.

    • Which comment said it was? “…it turns out that the established hypotheses are not confirmed…” is also not politically-inspired, and that is the only comment directed specifically at the abstract.

    • Much of the SLR in Jakarta, Indonesia is attributed to massive ground water removal and subsequent land subsidence is the result, with Jakarta sea level increasing at some of the fastest rates in the world. But this is while the land is sinking up to 15 cm a year (150 mm a year) , which some don’t include in their analysis of increased sea levels. Very disingenuous to not include the reason why. Half of Jakarta is now below sea level. As it is in many other regions, and/or manipulation of a major river with dykes/levies and the delta region which now gets less silt buildup, although the delta is still subsiding over long time frames such as New Orleans which is also sinking and much of New Orleans is under sea level.

      Holland is the perfect example of this problem, although I don’t know that massive ground water extraction is the problem there. However, the industrious Dutch have not only learnt to counter this and reclaim a lot of land, but they have to learned to accept this and go with the flow, so to speak. In certain areas of Holland, they are now building floating houses/buildings, and now it doesn’t matter much what the water level is since they are moored to posts that can float up to 15-20 feet, just in case there is a breech of a dyke and a high tide.

      Learning to adapt has to be the message, not thinking we can reverse climate change and sea levels by extension. That is just absurd, so let’s just plan to adapt to whatever happens. And maybe quit pumping out so much ground water if it is contributing massively to ground subsidence. With cheap fossil fuels, domestic water can be made from salt water with RO, or in many locations, they just use the salt water to flush toilets, assuming they even have flush toilets.

  5. What can you say with these weather worriers and doomsters. I have a mate on the south coast in Bega New South Wales and you’ll recall that was bushfire country last summer after the long drought. In July Bega had it’s wettest month for 98 years and it’s all runoff now-
    https://www.abc.net.au/news/2020-08-08/nsw-south-coast-flash-flooding-will-get-worse-severe-weather/12538396

    And here’s Tasmania copping it’s lowest temp on record and check out that cloud cover that we’re getting all over southern Australia at present-
    https://au.news.yahoo.com/weather-record-smashed-tasmania-liawenee-drops-14c-032814464.html

    So what as they only have BoM records for Liawenee in Tasmania’s Central Plateau for the last 20 years apparently. Lo and behold they pick up a Tasmanian minimum record when the whole of Australia only had a reasonable Stevenson Screen rollout by 1910 so it’s all just so much noise in the big scheme of things. Every Liawenee is famous for 5 seconds but how many missing Liawenees are there out there?

    • Correction: Bega’s rainfall in July 2020 was it’s wettest July rainfall most likely in living Bega memories. Not that it matters much to my mate who won’t be able to get off his property until the Bega River leaves his access road and Council can see what needs fixing again. Such are the vicissitudes of dairy country.

  6. I ran some numbers for a sea level rise essay in Blowing Smoke. In many places, ground water is largely replenished by the hydrological cycle. The proof is in the water level in wellsWhichnremains fairly constant. There are places where there really is ground water depletion, such as the Ogallala aquifer in the US (Center pivot irrigation)or in central India and Bangladesh with tube wells And the associated arsenic problem. But the volume of annual depletion measured in cubic kilometers of water is still de minimus concerning global sea level.

    • I remember Steve Fitzpatrick @ Lucia’s studied this and only found inadequate data about draining of the world’s aquifers.

      So here we have you, Steve, and Kout saying three different things. Do we really have no idea?

      By the way, from listening to all three of you for many years, I’ve gained a lot of confidence in the usual veracity of all of you, so this presents me with a dilemna.

      Flipping a three sided coin I find it lands with Kout’s head up. He, the accomplished hydrologist.
      =========

    • “…In many places, ground water is largely replenished by the hydrological cycle…”

      And in many places, it isn’t. Wells go bad/dry all the time and have to be replaced with deeper ones. Areas with a lack of surface water replenishment (e.g., lakes going dry) are more obvious. Even accepting your words at face value…the estimated volume of groundwater withdrawals each year is pretty close to the measured sea level rise. “Largely replenished” and “in many places” sounds like substantial groundwater losses collectively.

      “…But the volume of annual depletion measured in cubic kilometers of water is still de minimus concerning global sea level…”

      Define de minimus. 5%? 10%? Less?

      This article https://www.sciencedaily.com/releases/2010/09/100923142503.htm from 2010 said 25%.

      • I will now use math to define de minimus for you from a different mathematical perspective already computed in the SLR essay. You should calc up self rather than criticize obvious stuff: Just simple arithmetic.

        The worlds oceans are about 71% of its surface, and satellite measured are about 361E+6 KM2. Look it up. So one km^3 water (Or melted ice)adds about 2.78E-6 meters to SLR—2.78 microns. I leave that simple exponential arithmetic for you to verify, and also verify a micron as a millionth of a meter.

        Do the rest of the Groundwater math yourself. You now have all the necessary constants. De minimus means near zero. Within rounding error.

          • Good question to which I do not not know the answer. I have admired his previous work (Actually his Ph.D student’s) on station error and homogenization. See footnote 14 to essay When Data Isn’t in ebook Blowing Smoke for details.

            Essay Pseudo Precision in ebook Blowing Smoke does debunk earlier peer reviewed papers claiming the purported ~2005-2010 SLR deceleration was due to groundwater accumulation, the inverse of his statement.

            And I have guest posted here before on ‘Sea Level Rise, Acceleration, and Closure‘. Closure happens nicely from just thermosteric rise and ice sheet loss, needing no groundwater depletion term of any possibly measurable significance.

  7. If the hydrological cycle accelerates, how much energy is required to do that in lieu of heat?

    Heat us often a sign of inefficiency or waste in a system.

  8. So now the presence of the central and necessary “3X’s Greenhouse Multiplier” from increased atmospheric humidity (and therefore 3X’s increased LWIR Trapping) resulting from some minor CO2 warming…has been falsified.

    What besides its political “legs” is left of this hypothesis?

    • If half of sea level rise is from aquifers and if the rate of sea level rise is unchanged from before the spike of AnthroCO2 then the thermal expansion of the oceans is slowing.

      AnthroCO2 may be miraculously greening the earrh but it doesn’t seem to be combatting natural cooling very well.

      Shouldn’t someone let the IPCC know?
      ===============

  9. “with deintensification prevailing in the 21st century”

    NVAP also showed it gettnig drier. Well, there goes the water vapour feedback theory! Doubling CO2 can at most only cause a degree C of warming.

    • This report seems to deserve a lot more commentary than it is getting.

      If Koutsoyiannis is right then a lot of the physics underlying the climate alarm is wrong.

      As has been suspected.
      ==============

      • It does deserve more discussion, because water vapour is the elephant in the room, or in this case, the one that isnt in the room when it was supposed to have been.

        No WV increase is the one single devastating argument against CAGW.

      • Koutsoyiannis’s paper deserves a lot more commentary on the physics of climate.
        The current “physics” in climate science is nothing of the sort. The various physical parameters and equations are adapted to generate certain results in models. None(except perhaps from Russia) is working. None of the calculations can be done at a suitable fineness because there isn’t enough computer power in the world to deal with the processes at millimeter grid sizes.
        And finally, the IPCC admitted in the third? report that climate is a chaotic process and can’t be predicted regardless of whether or not it can be calculated.

  10. It might be of interest to the scientists involved in this paper to realise that what they are observing through their complex instruments and subsequent calculations may be seen and observed on a daily basis in our steam generating plants operating within the Rankine Cycle. Here the cycle RATE increases with an increase in energy input but the MASS of the working fluid remains constant as does both the temperature and pressure
    I suggest this is what they are finding in the atmospheric Hydro Cycle.
    Probably it will be found that the frequency of precipitation may increase with rising energy input but the quantity will remain stable.

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