Global warming and rain.

One day when I was a boy in Hokitika (West Coast, South Island, New Zealand) it was raining when I went to school and it got worse, so I had to walk home through water lying everywhere. The water was up to my ankles everywhere, and deeper in lower lying areas. This did not come from the river, but merely from the rain falling, and in nine hours, from memory there was nine inches of rain (a little under 23 cm). This was regarded as exceptional rain then, a once in a hundred year flood.

Now we have global warming so what do we expect? You hear lots of talk about drought, and yes in some parts of the world there will be drought, but in others there will be more rain. The reason is, if the oceans get warmer more water should go into the air. By itself that may not matter too much if the air gets warmer as well, but problems arise if such warm air meets cooler air. This is the sort of thing that causes rain, but now there is more water in the air.

What happens next depends on exactly how the cause behaved. The obvious thing is the rain falls, but when the humidity collapses into rain drops, its going from the gas phase to liquid releases a lot of energy. If there is enough cold air, it might just heat it, especially if the cold came from mountains forcing the air upwards relatively slowly so that it cools and rains on one side of the mountains. That is what happens around Hokitika. Now the hot air blows a strong warm wind over the land to the east, the so-called föhn wind. If the energy cannot be dissipated that way, then stronger circular winds are generated. The tropical cyclones are examples. There was one recently in Madagascar recently that did extreme damage.

So, how will global warming affect these? The short answer is, there will be a variety of ways. Stronger cyclones, more frequent cyclones (because milder systems that get stronger enter the classification) but the more obvious one is more rain because more water has been evaporated. Which gets me back to Hokitika. They have just had a weather system pass over that lasted about a day and a half of continuous rain, and dumped 800 mm of rain in that period (about 31 ½ inches). That is as much as some places get in a year. A little way inland, in the same period they got 1,082 mm, and that is almost 43 inches.

There has been a variety of flooding around the place. A number of houses were inundated because the storm-water drains could not cope and one woman died. Apparently she was driving; she did not like the speed of the water flowing down the road, so she got out. If when driving you see rapidly flowing water of unknown depth ahead, stop and sit it out, or turn back to higher ground. Do not enter. If you are correct in your fear that a car cannot maintain its grip on the road, you walking would be in a worse position. The force of rapidly flowing water will sweep you off your feet, and if it is deep, you are lighter and therefore have less grip. Your grip depends on your weight.

Probably the most frustrating situation has been for tourists south of the Franz Josef glacier, where they are stranded. To the south, the road is apparently cut off around Haast, and to the north of the Fox Glacier, the Waiho bridge was washed out by a river carrying down quite large boulders. A little earlier there were sightseers walking on the bridge, but fortunately they all got off before the bridge went. To give some idea of the water, here are links to two videos of the bridge going:   and The first one also gives a brief example of the New Zealand accent, and the vernacular. Note the bridge was a Bailey bridge and is in principle not expected to be permanent.

Once something like this happens, the blame game starts. One argument was that the river has a history of flooding and of eroding out the land and changing course, so why build a more permanent bridge? Another was the crossing is situated on a major fault and apparently the land is not good for foundations. I suspect that since it is in a very low population area, money is also a relevant issue. Where I live, there are a number of bridges across the Hutt river, and it runs along a major fault line, but being in a major metropolitan area, bridges are built. However, another more pertinent accusation came from a local who had complained a few days before that someone excavating the riverbed a little upstream had created a channel that would direct the heaviest rocks in a flood in the direction of the first supports to give way. Oops! No doubt more will follow.

When I wrote that (yesterday), the weather system was still to the south of here but working its way north. Yesterday we had wind gusts of up to 120 k/h, and while the system was working its way north, apart from some heavy rain last night, it had run out of steam. Today it is quite warm, sunny, no problem.

So is this a sign of climate change? A single incident is not, however I note that the “one in a hundred year rain event” in my youth has happened again now, and apparently in the 1980s. This time it has dumped almost four times the amount of water, and the Tasman Sea is about two Centigrade degrees above average this summer. You form your own opinion.

10 thoughts on “Global warming and rain.

  1. From my essay yesterday, which dealt with the nuclear fusion solution, after reinforcing the end:

    “As Greta said, we need to listen to science, knowledge. We need more knowledge to get out of this mess. The alternative is the old fashion way: reduce human population massively, by culling. A good nuclear winter and killing 95% of humanity would give the biosphere a respite.

    Otherwise, the most recent research (2019) shows that the atmosphere could heat up so much that clouds won’t form as they do now, and a further jump of eight (8) degree Celsius would occur. That is astounding. But it’s not just a theory. Actually, it was the other way around: such jumps were found in the fossil record, and couldn’t be explained… until now. Now that we have found that a tripling of the CO2 would make clouds disappear.

    That explains why crocodiles have, more than once in the past, enjoyed the Arctic ocean, and sunned them on beaches in Greenland graced by palm trees.

    After such a jump of eight degrees Celsius globally, from the disappearance of clouds, on top of a rise of five degrees, at least half of the presently inhabited lands would be too hot for biological life, aside from the sort of bacteria which live below volcanoes (thermophilic bacteria). Is that what we want?

    If that’s not what we want, there is only one solution: more brainiacs, more science, enough of it to replace the 90% of present day energy production by thermonuclear fusion. At this point, it’s just a matter of building big reactors.”

    • Extrapolating from Jurassic times is a bit dangerous because the land configuration was wildly different nevertheless large animals thrived so life was possible. Land plants thrived otherwise the dinosaurs could not have survived, so there must have been rain. It was ten degrees hotter then.

      But I agree fusion is a great technology, except we can’t make it work yet. I agree we need more science devoted to this problem right now because I don’t think one single solution will work, at least no quickly enough. I commented on your post, which was a good one, but I think the thorium molten salt reactor would be a quicker intermediate solution. Unfortunately, the world is installing a new coal-fired power plant every week and they will have to continue running so we have to do something else as well. I think some form of geoengineering will have to be tried because we need an answer quickly.

      • The jump of 8 degree Centigrades was seen in computer models with three times the CO2. It explained what happened during Jurassic of Miocene…. Life was next to poles. Much of the equatorial zone was probably bereft of advanced life… ???

        We can’t make fusion work… because we don’t spend enough on it. It works enough in Tomahawks to tell us energy production is possible (within large reactors and with some Tritium…)

        Thorium has problems in the details (Thorium reactors were made to work more than 50 years ago). If one tried to develop energy replacement Thorium, one could probably make it work before fusion… Yet a full blown energy producing fusion reactor is probably constructible NOW. It’s just a matter of spending 200 billion dollars within ten years…

        Geoengineering will not work. Be it only for political reasons.

  2. Patrice Ayme Says:
    March 31, 2019 at 12:17 am | Reply edit
    From Max Planck institute on Stellarator (2018):

    … its latest round of experiments have achieved long-lasting plasmas of more than 100 seconds for the first time, a record for this kind of stellarator. What’s more, they are also reporting unprecedented energy yields, brought on by newly installed components that inject fast hydrogen atoms into the plasma stream.

    This resulted in high plasma densities of 2 x 1020 particles per cubic meter, which according to the scientists, are values sufficient for a future power station. The energy content of the plasma exceeded 1 megajoule for the first time ever, without the vessel walls becoming too hot. The plasma temperature, meanwhile, hit 20 million °C (36 million °F), exceeding the Sun’s [CORE] temperature of 15 million °C ( 27 million °F).

    “Congratulations to the Wendelstein 7-X team on the new world record,” said Germany’s Federal Research Minister, Anja Karliczek. “The approach is the right one – in this way, important new findings have been made for the future use of fusion power stations. Alongside renewables, fusion energy could be the energy source of the future. The researchers in Greifswald have taken an important step in this direction with their work. I wish the team every success with their future work.”

    Though more than a million assembly hours went into the initial construction of the Wendelstein 7-X, the stellarator remains a constant work in progress. In September 2017, the interior walls of the container were fitted with graphite tiles, allowing for higher internal temperatures and longer plasma discharges. Though these proved pivotal in the team’s latest success, they are already due to be replaced with water-cooled elements made from carbon fiber.

    This will help the team work toward its aims of continuously containing super-hot plasma in the Wendelstein 7-X’s contorted magnetic fields for more than 30 minutes at a time. Though the device is not actually designed to produce energy, if it can be achieved, this highly elaborate proof-of-concept device would provide compelling evidence that stellarators, and nuclear fusion, can form part of an environmentally sustainable energy mix. Though, for now, that still remains a big if.

    Source: Max Planck Institute for Plasma Physics

    • … ten to the power 20 got lost in the shuffle… Should have read:
      ….high plasma densities of 2 x 10^20 particles per cubic meter, which according to the scientists, are values sufficient for a future power station

    • I agree fusion is the the answer if we can get it to work, and I am sure that sooner or later it will be made to work. However, because of what CO2 is there already, I still think we need some geoengineering. Replanting the tropical rain forests might be a start, and instead of arms using lime, they could achieve the same with crushed peridotite, or a similar rock, and absorb CO2 at the same time. I know the political scene is bad for it, and it will probably end up like Brexit, where the politicians are against everything.

      • For geoengineering some countries will object… One of the reasons being that global warming is not bad for everybody. Some regions are getting much more hospitable even habitable under it… And I am not just talking about agriculture in Antarctica (a more distant possibility).

        Russia, Canada, Scandinavia, for example are obviously secretly for warming.
        Also geoengineering will cause problems, and accusations will fly… Between nations. Replanting tropical rain forests will stay a pipe dreams as nations controlling them are hell bent to eradicate them. You would need to send the Marines. How much CO2 can be absorbed quickly with rocks? Crushed peridotite? What energy will crush it?

        And wait until fusion and, or Thorium starts to work, with enormous renewables in, say the USA (lots of sun, mountains, thus wind, hydro). Then fossil fuels will be outlawed, and fossil fuel plants bombed…. More US bait and switch foreseeable in the future… for everybody’s good, of course. Same old same old….

  3. Patrice, what you say about objections probably will happen, and geoengineering is probably out unless the nations agree, but even the US might see sense when all its coastal cities start to get inundated, when there are a billion people that are climate refugees because their land is underwater, and when another billion threaten to starve to death. It makes bad TV viewing at dinner time, if you have any dinner. Of course, then it is getting a little late in the day.

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