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Bandwagon Of Doom Washed Away By Tidal Wave Of Data

April 2, 2020

By Paul Homewood



Global warming theory states that a warmer climate should lead to increasing water vapour in the atmosphere, and thus to more floods and droughts.

The actual data however does not agree.


According to the Intergovernmental Panel on Climate Change, for each degree of global warming, the amount of water vapour in the air should increase by about 6-7%. As with so many things the IPCC talks about, this small change is supposed to lead to calamity. That’s because increasing water vapour is supposed to lead to “intensification of the hydrological cycle”, in other words floods and droughts.

Demetris Koutsoyiannis, a hydrologist at the National Technical University of Athens, has taken it upon himself to undertake a major review of the scientific data to see what evidence there is for this actually happening in practice. His findings, currently up for open peer review at the journal Hydrology and Earth System Sciences,[i] make for uncomfortable reading for the IPCC and its fellow-travellers on the bandwagon of doom.

It seems, for example, that although relative humidity is supposed to stay constant under global warming, it is actually falling. Dew points are supposed to be increasing, but mostly they are not; in particular there appears to be little or no change in equatorial regions, where the largest share of evaporation of water from the oceans takes place. If we’re not seeing change there, then increased flooding is off the agenda.

And Koutsoyiannis finds that the amount of water vapour in the air is increasing at roughly one third of the IPCC’s predicted rate. If the rate of water vapour increase really is so low, then by the time we hit the (in)famous two-degree target for global warming, we’ll still only have experienced a 4% increase, which as Koutsoyiannis points out is negligible given the normal variability of hydrological cycles. Where are the deluges and floods going to come from?

It doesn’t end there either. There are lots of other ways in which intensification of the hydrological cycle might show up. You can measure the amount of water vapour in columns of the atmosphere. That should be increasing with global warming too, right? Koutsoyiannis finds no trend. Average rainfall across the planet should increase too – the IPCC says by 1-3% per degree of global warming. The problem with this claim is that it’s within the “noise” of normal variability anyway; no surprise then that Koutsoyiannis sees no meaningful trends in the data. The limited data on evaporation are telling the same story (or lack of one) too.

What about extremes of rainfall? Koutsoyannis reviews a variety of measures: changes in daily maxima, days with rainfall over a threshold and so on, he looks on land and he looks at sea. And he draws a blank everywhere.

As well as being an eminent scientist, Koutosoyiannis also has a deep interest in the scientific knowledge and practice of the ancient world, and this has coloured his view of the climate scare. As he says in his conclusions, the small changes that are exciting climate scientists today would not even have been discussed by ancient engineers, who would have seen them as just noise in the ever-changing patterns of hydrological cycles. Similarly, he points out that such small changes are of no interest to those making practical decisions about flood protection and water storage. And he wonders whether, with the data refuting the climatologists’ predictions so clearly, it isn’t time that hydrologists shifted their attention away from prophecies of doom, and back onto making a real contribution to people’s lives.

You can see his point.

  1. P Dean permalink
    April 2, 2020 4:18 pm

    The paper and data can be dowloaded from the journal. Its a nice long read of 49 pages. Journal of hydrology and earth systems sciences. All open access.

  2. bobn permalink
    April 2, 2020 4:19 pm

    Can humidity be used as a proxy for temperature?
    We have gross uncertainty about what global temperature changes really are with extrapolations, adjustments and downright fraud everywhere. Could rising or falling global humidity give a better idea of global temperature changes?

  3. Phillip Bratby permalink
    April 2, 2020 4:41 pm

    I can’t wait to see this given publicity by Harrabin et all at the BBC.

    • Michael permalink
      April 2, 2020 5:33 pm

      You’ll be waiting along time methinks

    • David A permalink
      April 2, 2020 7:35 pm

      Hi degree is in English. He may not understand it.

  4. Philip Mulholland permalink
    April 2, 2020 5:14 pm

    Demetris Koutsoyiannis is one of the good guys.

  5. April 2, 2020 6:58 pm

    That’s because increasing water vapour is supposed to lead to “intensification of the hydrological cycle”, in other words floods and droughts.

    If more water vapour can mean more droughts, what would less water vapour mean?

  6. jack broughton permalink
    April 2, 2020 9:13 pm

    This paper will take me a long time to work through, but is very exciting.
    It seems that the cloud cover round the world has reduced slightly since the 1970s when clean air acts were enacted, followed by the East European de-industrialisation of the 1990s. The dust particles needed for drop nucleation were apparently reduced. I had thought that this would mean more humidity, but apparently not: ie. the reduced cloud cover carries the same rain.

    The point that he makes about historical variance is what none of the modellers seem to be aware of, they think that the climate began in 1970.

  7. April 2, 2020 9:22 pm

    Demetris Koutsoyiannis has also written a number of papers on the chaotic behavior of climate in general and hydrology in particular.

  8. Matt Dalby permalink
    April 2, 2020 11:53 pm

    If the amount of water vapour in the atmosphere is not increasing as fast as the IPCC predicted this must mean that they have also over estimated the water vapour feed back (the assumption that CO2 will cause some warming which will lead to more water vapour in the atmosphere which causes more warming). Therefore the IPCC’s estimates of climate sensitivity are far too high. Will this paper be used to help generate AR6? Somehow I doubt it.

    • Colin MacDonald permalink
      April 3, 2020 12:31 pm

      Relative humidity levels have been in long term decline, another inconvenient truth to the positive feedback needed for IPPC models of global warming, of course this real world data does not get incorporated in the latest models.

  9. April 3, 2020 12:03 am

    Reblogged this on Roald J. Larsen.

  10. NeilC permalink
    April 3, 2020 5:17 am

    Surely, more sunshine impacts to less Relative Humidity and the drier the air allows temperatures to rise more readily. Inversely, less sunshine, higher RH and lower temperature. Considering the last and current solar cycle with a weaker sun, one would expect higher RH and lower or temperature stasis. Which is exactly what has been happening in the UK for the last 21 years..–liquid-and-gas-controls-weather-and-climate

  11. Stonyground permalink
    April 3, 2020 8:45 am

    Anyone who has spent any amount of time reading this blog will know a lot of this stuff already. The thing that proves to me that I am on the right side is the relentless supply of graphs that show no trends over long periods of time. It has become ever so slightly warmer, basically that is the whole of climate change in a nutshell. It is a tragedy the amount of money that has been wasted on this non problem.

  12. Steve permalink
    April 3, 2020 5:59 pm

    I am confused. Water vaper is increasing slightly but relative humidity is decreasing. Can someone explain this?

  13. April 4, 2020 11:25 am

    For those acquainted with the Rankine Cycle the answer is obvious; for in this cycle an increase in energy input does NOT result in an increase in the MASS of the working fluid. It merely increases the RATE of the cycle. This is why our steam plants operate as closed systems.
    The Hydro Cycle acts as a Rankine Cycle, thus there will be little effect on water content in the atmosphere in the event of an increase in energy input, say due to the Greenhouse Effect.

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