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Kerala Floods “Likely Due To Climate Variability, Not AGW”–New Study

January 5, 2019

By Paul Homewood

More fake climate disaster claims from Christian Aid:




And the reality?



Flood is among the deadliest disasters in India, and the frequency of floods and extreme precipitation events is projected to increase under the warming climate. The frequency of floods in India varies geographically as some regions are more prone to floods than the others. The Kerala flood of 2018 caused enormous economic damage, affected millions of people, and resulted in the death of more than 400 people. Here we provide a hydroclimatological perspective on the Kerala flood of 2018. Using the observations and model simulations from the Variable Infiltration Capacity (VIC) model, we show that the 2018 extreme precipitation and runoff conditions that caused flooding were unprecedented in the record of the past 66 years (1951-2017). Our results show that mean monsoon precipitation has significantly declined while air temperature has significantly increased during 1951-2017 in Kerala. The drying and warming trends during the monsoon season resulted in a declined total runoff in large part of the state in the last 66 years. Apart from the mean hydroclimatic conditions, extreme precipitation, and extreme total runoff have also declined from 1951 to 2017. However, 1 and 2-day extreme precipitation and extreme runoff conditions in August 2018 exceeded substantially from the long-term 95th percentiles recorded during 1951-2017. Since there is no increase in mean and extreme precipitation in Kerala over the last six decades, the extreme event during August 2018 is likely to be driven by anomalous atmospheric conditions due to climate variability rather anthropogenic climate warming. The severity of the Kerala flood of 2018 and the damage caused might be affected by several factors including land use/ land cover change, antecedent hydrologic conditions, reservoir storage and operations, encroachment of flood plains, and other natural factors. The impacts of key drivers (anthropogenic and natural) on flood severity need to be established to improve our understanding of floods and associated damage.


In short, extreme rainfall in Kerala has been declining over the years. It is likely that the heavy rainfall last August was nothing more than a weather event, and nothing to do with global warming.

There are of course thousands of places around the world where all sorts of new records can be set, particularly when historical data only goes back a few decades.

Every year, many such events will occur. But this does not mean that extreme weather is getting worse.

  1. Ian Magness permalink
    January 5, 2019 11:17 pm

    No coincidence that this rational approach was detailed in a geological journal. We geologists and former geologists are, by and large, sceptical of AGW. Indeed, the only 3 others that I am in touch with from my degree (not a great sample I appreciate) are all total deniers.

  2. markl permalink
    January 6, 2019 1:57 am

    It’s hard to ignore the facts.

    • pitsgate permalink
      January 6, 2019 11:14 am

      Depends which facts you’re talking about. Which ones are you referring to?

      • Mike Jackson permalink
        January 6, 2019 11:17 am

        Apologies for the misleading “pitsgate” user name, folks. Every now and again wordpress defaults to an out-of-date domain!

    • Gerry, England permalink
      January 8, 2019 1:51 pm

      But they do a very good job. Fingers in ears, la, la, la…..

  3. John F. Hultquist permalink
    January 6, 2019 1:59 am

    worst flooding in 80 years …

    So what caused flooding prior to 80 years ago?

  4. January 6, 2019 2:49 am

    See also an insightful article by Jonathan Eden: Why it’s so hard to detect the fingerprints of global warming on monsoon rains

    Some excerpts:
    Unlike temperature, rainfall varies hugely in space and time. Even the most sophisticated climate models struggle to simulate physical processes such as convection and evaporation that drive rainfall activity. On top of that, global warming is not expected to change the frequency and intensity of rainfall extremes in the same way in all parts of the world.

    The choice to focus solely on the rainfall itself is particularly relevant for flooding events. Though accusations of poor decision-making and mismanagement of water resources are beginning to appear in the Kerala aftermath, the floods simply would not have occurred without a significant amount of rain.

    But for rainfall in particular there is a discrepancy between what we understand about the general effect of global warming and our rather lesser ability to quantify the climate change fingerprint on specific events.

    And of course Mike Hulme goes into detail why attribution is problematic for such events:

  5. Gary Kerkin permalink
    January 6, 2019 3:15 am

    Every year, many such events will occur. But this does not mean that extreme weather is getting worse.

    Many such events might occur. For example the absence of severe tornados in the US during 2018.

  6. January 6, 2019 9:19 am

    projections of future climate change have shown

    Aka crystal ball gazing. Meanwhile one weather event gets blown out of all proportion by climate propagandists trying to blame man for anything and everything.

    • Paul permalink
      January 9, 2019 4:07 pm

      Projections of the future can’t “show” anything until the future happens and we can see whether the projection was accurate. So far, projections in the past about what we’re experiencing now were woefully inaccurate.

  7. mothcatcher permalink
    January 6, 2019 9:57 am

    “…There are of course thousands of places around the world where all sorts of new records can be set, particularly when historical data only goes back a few decades.

    Every year, many such events will occur. But this does not mean that extreme weather is getting worse..”

    Very well put, Paul. This can’t be repeated often enough!

  8. January 6, 2019 10:03 am

    “Warmer air can hold more water” … and so can bigger baths, but will do so only if extra water is supplied, and the supply of water is controlled by the temperature of the oceans, so look for pools of warm seawater if you want to explain rises in precipitation.

    Everything can cause rises in seawater temperature, such as changes in sunshine or ocean currents.

  9. January 6, 2019 12:19 pm

    Since they want to bring history into the mix, let’s really do it up. Likely the monsoons were “created” when India smacked into Asia, thus raising the Himalayas. Now that will change your weather. How that was Donald Trump’s fault has yet to be determined.

  10. January 6, 2019 12:32 pm

    “Global Warming” may have made these floods LESS severe, because monsoon failures are expected to become more frequent:

    … though the research came from the Potsdam Institute, where many ex-STASI employees went to work when the Berlin wall fell.

  11. Joseph permalink
    January 6, 2019 5:59 pm

    The cause of the sudden heavy flooding was only due to opening of the shutters of some 30 plus dams (Which were full and many of the overflowing) almost at the same time. True we had heavy rains. But had the dam management released water little by little we wud never have seen this immense damage. Kerala is not new to rains. The dam management is totally to be blamed.

  12. Gamecock permalink
    January 8, 2019 8:09 pm

    ‘the extreme event during August 2018 is likely to be driven by anomalous atmospheric conditions due to climate variability’

    Climate doesn’t have variability. Weather has variability. It’s obvious that they don’t even know what “climate” means.

  13. Paul permalink
    January 9, 2019 2:45 pm

    Take a look at the bibliography at the end of this report. Out of the 91 references, only 4 are from peer-reviewed journals, and those were Nature and Scientific American, neither of which is famous for its lack of bias when it comes to AGW. Most were from news articles. Where’s the science?

    • January 9, 2019 3:09 pm

      I presume you mean the Christian Aid report?

      • Paul permalink
        January 9, 2019 4:02 pm

        Yes. It’s a typical example of not supporting their arguments from scientific sources. It’s also noteworthy that they used the IPCC to claim “the only way to prevent the escalation of extreme weather is to immediately rapidly cut greenhouse gas emissions” but ignored its statements in the same report which said that there is little evidence to support the idea that extreme weather events are caused by greenhouse gas emissions, which is the premise behind their entire report!

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