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Friday, 16 August, 2002, 12:49 GMT 13:49 UK
European floods: your questions answered

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  • Click here to read the transcript


    South-eastern Germany is facing a catastrophe as flood waters surge downstream from the Czech Republic, causing the Elbe river to burst its banks.

    Parts of Dresden, including the central train station, are under water and hospitals are being evacuated as a second wave of flood waters is expected to sweep through the region.

    The situation in Prague is easing after fears on Wednesday that the Vltava river would burst through flood defences and swamp the architectural treasures of the Old Town.

    Why are the floods happening? What causes such unseasonal weather?

    Michael Fish answered your questions on the severe weather in Europe.


    Transcript


    Newshost:

    Welcome to this BBC Interactive forum. The worst floods in Czechoslovakia for 500 hundred years, 800 people killed in flooding in Asia and of course the ever-present sinister threat posed by global warming. So does this appalling weather signal a long-term change in the Earth's climate and is it our fault? One man who might well be able to answer some of the many questions you sent us is Michael Fish the BBC weather forecaster.

    The first question is from Craig Wallace in the United Kingdom: Some experts have suggested that the unseasonable weather may be linked to the southern position of the jet streams over the last couple of weeks, steering storms farther into the European continent. Do you agree with this, and if so, what might cause such a displacement?


    Michael Fish:

    Well it's certainly not a suggestion, it's fact. This gentleman was probably watching me on BBC1 a couple of evenings ago because I did actually show some graphics to explain that as best I could in 30 seconds as it were. But yes, that is the reason - 100%.

    The jet stream is the controlling influence over the world's weather systems. It controls where they develop, when they develop, where they go etc. In an average summer, that jet stream would normally flow across the Atlantic and pass between Scotland and Iceland and all the areas of low pressure would be in that area. This year the jet stream has taken a dive south and it has moved across the British Isles and curling down into Central Europe and hence the areas of low pressure and all the rain have been steered in that direction.


    Newshost:

    Do you know why it has gone further south?


    Michael Fish:

    It is an extremely variable thing. It meanders around all over the globe - different directions, different tracks, different days, different months - and it's just one of those things that happens every now and again.


    Newshost:

    Cerys, Wales: Would reforestation programmes help reduce severe flooding like this in spite of the apparent effects of global warming, if so what is being done in Europe and the UK to promote tree planting on a massive scale?


    Michael Fish:

    Well I can't really answer that because I'm neither a hydrologist nor whatever somebody to do with trees is called. But yes, obviously people reading the press and that is the answer - a lot of the problems are caused by man with deforestation. I am sure that if you plant the trees back again, it will do nothing but good.


    Newshost:

    Tim Osborne UK: Is it true that the Gulf Stream has slowed down due to the warming of the Arctic not pushing cold water South? If this is the case, will we not end up with warmer summers and much colder winters?


    Michael Fish:

    There is no evidence whatsoever that that is happening at the moment. But one of the scenarios that is coming out of the research that has taken place over the last few years into global warming and no doubt will be presented at the Johannesburg conference later in the month, is that that could happen - we're not talking about tomorrow, we're talking about in the centuries ahead. So it's not something that has happened but it is one of the possibilities that that might happen as a result of global warming, that the Gulf Stream could either be deflected, slowed down or completely stopped and there would therefore be massive implications on the weather patterns in Northern Europe because the whole thing is controlled by the Gulf Stream. We have extremely mild winters compared to what we should have because of the Gulf Stream, so there would a vast change. But nobody knows whether that's going to happen or not - it's just the computer has produced all these various scenarios as to what might happen in hundreds of years time and that came out as a possible solution but you or I won't be around to see whether it's true or not.


    Newshost:

    Chris Staite, New Zealand: Flooding is increasing world-wide. Why, when unprecedented numbers of people are living on floodplains, the natural hydrology of rivers has been altered immensely, rivers have been restrained to small areas of their natural floodplain, and catchments have been sealed or cleared, is the blame falling entirely on weather patterns. Rather, shouldn't the effect of human activity on natural flow patterns, and settlement of flood prone areas be held accountable?


    Michael Fish:

    I think he has answered his own question - the answer is yes but again it's not my field and I can only quote things that I've read in the paper and commonsense. You don't have to think about it very long to realise that if you mess around with a river, you are going to have to pay for it in some way or other and people at long last are beginning to sit up and wonder why they put houses in silly places and have cut down the forests and redirected rivers etc. Now I suppose with hindsight, it's commonsense - you think to yourself yes, that was bound to happen but people perhaps didn't think about it years ago.


    Newshost:

    M.D. USA: Are the entire world's weather patterns changing because of mankind's destruction of the earth by his pollution?


    Michael Fish:

    Yes, yes - this is global warming. This is the scenario I was talking about a little while ago - the various computer models that have been run to project what will happen in the future to the world's weather patterns as a result of the stupidity of man in the past 100 years or so. Already we've seen quite a considerable warming of the Earth's climate and we've seen a change in the weather pattern and changes will continue in the decades and centuries ahead unless we do something to stop it - unless we stop polluting the atmosphere. We are locked in to an inevitable change which we can't do anything about.


    Newshost:

    There are people who say that it's all a lot a nonsense put around by liberal Guardian-reading scientists that are scaremongering - that actually there isn't really any proof that global warming is taking effect.


    Michael Fish:

    The facts are there. The facts have been there for years - they're plain enough to see - there is no doubt about it and there hasn't been any doubt for years and years.


    Newshost:

    Tim Antrobus, England: Do you think the recent flooding in Central Europe is a result of "global warming", or a one off event, occurred by "chance" so to speak?


    Michael Fish:

    That's something we can't answer - a massive amount of research would have to be done on that and you wouldn't be able to answer that question for many, many years. Off the top of my head, this happened in 1890 - very similar floods - there was no global warming then - the Industrial Revolution had hardly begun, man was not polluting the atmosphere. There were similar floods in 1890 to what we've got now - so maybe there is a connection - maybe there isn't. But you certainly can't point a finger in any one direct to point the blame as yet.


    Newshost:

    Ann, London, UK: Is this really global warning? I remember years ago at school studying about Europe and reading that it used to be a lot wetter and warmer and that the climate generally cycles through phases.

    I've also read somewhere that there are Ice Ages and that at some point we're due to go back into an Ice Age. Is it not possible that we could be counter-balancing that natural cycle?


    Michael Fish:

    We've done that already. The Earth's climate at the moment should have been cooling. We were supposed to be on a cooling cycle but man's intervention has not only overridden that but completely reversed it. The last decade has been the warmest years that we've ever recorded and the temperature is continuing to increase when naturally it actually should be slightly decreasing.


    Newshost:

    Philip Whiteman, UK: I read that part of the cause was the unusual tracking and route for low pressure systems passing over continental Europe for this time of year. If this is correct, what are the reasons?


    Michael Fish:

    The reason was that the jet stream has been diverted further south and it does wander about - I don't know whether its got a mind of its own, it probably hasn't - we haven't done enough research yet to see whether there's any link between the track of the jet stream and global warming. But that was reason as I mentioned earlier - that instead of it passing between Scotland and Iceland as it should do in a normal year with the Azores high pressure area covering southern Europe, the jet stream took a dive into Europe and the Azores high retreated back onto the Atlantic and therefore of course they didn't get their normal settled summer - they ended up with a pretty cool wet one instead.


    Newshost:

    William Lack, England: Are natural oscillations in the jet stream normal and does it also have anything to do with El Nino?


    Michael Fish:

    I don't think so. No the effects of El Nino normally only affect the tropical part regions of the Earth. Mind you in the tropics they do have jet streams of their own but they're rather different with some of them coming from the easterly direction, whereas normal jet streams in the higher latitudes come from a westerly direction. As far as I am aware - and it may change because research is going on all the time and it's extremely complex to analyse whether data going back over the centuries and try and project ahead to the next centuries. But at the moment the current thinking is that it's probably unlikely that El Nino has any effect whatsoever on the weather in northern latitudes - places like Europe - most of it is restricted to the tropical regions, parts of South America across to Australia, India - those sort of parts of the world.


    Newshost:

    We've talked about El Nino, we' talked about global warming - there are a whole range of different factors which can affect the weather. I was reading over the weekend that this new brown haze - this cloud over Asia - is also having a big knock-on effect.


    Michael Fish:

    Absolutely - that's man's pollution again. That's yet another example of it. At least El Nino is a natural event that isn't caused by man and has been going on for thousands of years, perhaps millions of years - it's just one of these things that we've only recently discovered and the reason we've recently discovered it is because we've got weather satellites and you can look for a space down on the Pacific Ocean and see these temperature changes taking place - something we didn't know much about until a few decades ago. But everything else is manmade - that smoke over Asia in the winter is due to them burning fossil fuels and of course it has an adverse effect, not only on their health but possibly on the weather as well.

  • See also:

    15 Aug 02 | Europe
    15 Aug 02 | Europe
    14 Aug 02 | Europe
    15 Aug 02 | Business
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