Source: BBC TV: Newsnight
URL: N/A
Date: 23/08/2010
Event: Kirsty Wark presents BBC Newsnight: Floods in Pakistan
People:
Kirsty Wark: The disastrous floods in Pakistan - is global warming a factor?
Tonight, more flooding, more disease and 20 million homeless. Pakistan is reeeling from this still-unfolding disaster. What role, if any, has climate change played and, after "Climategate", are scientists more reluctant to blame global warming for natural disasters?
Good evening. The flooding in Pakistan was "beyond our worst nightmares," the chief executive of the Disasters Emergency Committee said today, with 20 million homeless, new areas still being flooded, the threat and reality of disease and at least 16 hundred people dead. Brendan Gormley praised the generosity of the UK - so far more than 29 million pounds has been donated - and called on the international community to give more. But are we any clearer as to the reason or reasons why the country has been deluged by the worst floods in almost a generation? Some climate scientists say that global warming has been a major contributing factor, but is this true? Our science editor Susan Watts reports.
Susan Watts: Millions of desperate people have been forced from their homes by weeks of floods. Many are now equally desperate to return to the villages and animals they left behind, despite forecasts of more rain to come. And the struggle to understand what has happened here is just beginning.
Some of the weather systems at play are well-recognised. The annual monsoon is no surprise in itself.
Rob McElwee: It's a result of the sun warming the Himalayan Plateau, drawing in air then from the warm ocean, the Indian Ocean, lifting over the high ground of India and falling as rain. Now this particular year, of course, it wasn't that smooth. We had the western arm curl around over India and up into Pakistan, but it went a long way north, and it joined in with some help in the uplift because of what was happening in the upper atmosphere, and this rain was extraordinarily heavy. It was about almost a whole monsoon season's worth in two days, fell in northern Pakistan, and the result of that, now of course, is flowing downriver.
Susan Watts: Aside from the monsoon itself, is it fair to say there are other weather systems that may be influencing what we're seeing?
Rob McElwee: Yes, there's one very major weather system which you'd have heard - everyone would have heard of - El Nino. But that's only one side of an oscillation. El Nino - Southern Oscillation - that's the male side. The female side - La Nina - is, if you like, the opposite. One weakens the monsoon - that's El Nino. One strengthens it - that's La Nina. And that's the one we're going through at the moment.
Susan Watts: But what about global warming? Most climate scientists say it's not possible to say any single extreme weather event is caused by climate change. And they stress the huge uncertainty in our understanding even of the basic systems of monsoon flooding, let alone any impact from climate change. There have been two weather patterns at work - the monsoon plus very disturbed weather over the north of the Asian continent.
Professor Julia Slingo: We've seen, as we know, the Russian fires, the Russian heat wave and also, further to the east, the floods over China. And it's the interaction of those two weather systems that led to the devastating storms over northern Pakistan - the mountains of northern Pakistan - at the beginning of August and again later in this month. Whether there's a climate change element - too difficult to tell at this stage, but we certainly know from rainfall records in India and China that there is an increasing trend towards heavier rain when rain is already heavy. So we expect extreme events like that to become more extreme as we move into a warmer world.
Susan Watts: Some meteorologists are prepared to go further, when asked: are we already beginning to see the impacts of climate change play out?
Lord Julian Hunt: Oh well yes, I think so, and that's why last year we had a sort of high-level specialists' meeting in the United States, as experts. All of whom were concerned with these changing meteorology and precipitation patterns associated with high mountains. There's a been tremendous effort to produce more and more accurate global climate models, but they are still not able to really model reliably these processes like the monsoon and the El Nino, and particularly how they interact with mountains, and then the effects... So that it's really important to actually have a quite focussed activity but I think at a more fundamental level, much more work needs to be done.
Susan Watts: Others, though, argue that natural cycles in the monsoon still dominate, and dismiss any role from human-induced climate change. Though that's not to say people are not having an impact.
Dr Robert Bradnock: Well, I certainly believe that what we're seeing at the moment is within the scale of natural variability. Well within the scale. You look back at the tremendous floods in the Indus Basin of 1973, going back 40 odd years. You go back another 20 years and you have similar catastrophic floods. And as you go further back in time, although the evidence is less statistically based, if you like, there's still abundant evidence of huge flooding, going right back to the time of the Indus Valley Civilisation. When you look at the foothills of the Himalaya, the deforestation of some of the very steep, and very weak, slopes undoubtedly has made a major contribution to to increased runoff. Some of the huge dams in the foothills of the Himalaya are only expected to have a lifespan of 50 or 60 years, because they're filling so much with erosion sediment. None of this is to do inherently with climate, but it is to do with human influence.
Susan Watts: One area of agreement is that there's no time to waste in working out what's happening, if vulnerable societies are to be better equipped to cope, if this is a taste of what a warmer world looks like.
Kirsty Wark: Susan Watts. Well, I'm joined now from Seattle by Dr Ghassem Asrar, Director of the World Climate Research Programme, and from Edinburgh by Andrew Montford, blogger and author of The Hockey Stick Illusion: Climategate and the Corruption of Science. Gentlemen, first Dr Asrar, do you think global warming has played a part in the Pakistan disaster?
Dr Ghassem Asrar: We can definitely say that probably the warmer atmosphere has contributed to enhancement and a strengthening of some of these monsoonal systems. Because fundamentally our planet is warmer by about one degree Fahrenheit, as compared to the past century. This excess heat has to be absorbed by the oceans and some of it is retained in the atmosphere. A warmer ocean - the Indian Ocean - as was evidenced by the surface temperature of the Indian Ocean being roughly about one degree warmer, would result in greater evaporation of water, and a warmer atmosphere tends to hold greater amount of water vapour. Under normal circumstances, the atmospheric circulation will basically distribute this excess water vapour over a larger area, and as a result the greater precipitation would really not be affecting as much as it did over this area. So this blocking of the air over Russia resulted in release of this excess water over a shorter area and over a shorter period of time.
Kirsty Wark: Thank you. Andrew Montford in Edinburgh, do you agree that that did play a role in Pakistan?
Andrew Montford: I don't think you can say that what happened in Pakistan was due to climate change. I don't think I disagree with anything that Dr Asrar said. If the world does get warmer, it is expected that precipitation will be higher. So I think there probably is widespread agreement on that. But that still doesn't mean that you can point to what happened in Pakistan and say: that is due to climate change. I think, as Susan Watts said in her original piece, there is a very widespread agreement on this - you cannot point the finger at individual weather events and say they are due to climate change, which is a long-term thing.
Kirsty Wark: Yeah but if we - there's an acceptance that the world is warming up and there's greater precipitation, do you think, Andrew Montford, that means that there can be, as it were, preemptive action taken? Because with the monsoon season, do you think that, I don't know, more levees or dams or whatever, that actually there should be some proactive work done, Andrew Montford?
Andrew Montford: I think that's probably a question for an economist - the different routes that people could take. Yes, almost certainly, there are things that people can do. One of the speakers in the piece pointed to the problems of deforestation leading to greater runoff, and yes, certainly things can be done to mitigate against that, certainly.
Kirsty Wark: Do you think that that should be, Dr Asrar - in Pakistan this year, of course, this has become too late - but if this is going to be a recurring pattern, and that perhaps we are going to see greater precipitation, then there can be preemptive action taken, after this particular disaster?
Dr Ghassem Asrar: Well, clearly we have to examine the possibility of re-occurrence of this magnitude events into the future, because this is the basis, the information that we provide about the magnitude and the frequency of the 100-year events, is what is used for developing or designing the bridges, dams for our water storage, as well as the entire infrastructure. If indeed -
Kirsty Wark: And Dr Asrar, sorry to interrupt, I just want to put this to you. Do you think, Dr Asrar, that after so-called Climategate, climate scientists are perhaps a bit leery, a bit cautious of pronouncing on what could be aspects of global warming because, as it were, their fingers have been burned?
Dr Ghassem Asrar: The scientists have always been very cautious, as was suggested, not to really draw conclusions based on one set of observations. But my answer, personal perspective is that yes, we have become more cautious, wanting to make sure that we gather as much evidence as we can in order to draw any conclusions, more so than in the past.
Kirsty Wark: Yes, and Andrew Montford, do you accept that climate change is a grave risk facing us all?
Andrew Montford: From my perspective, I think the answer is I don't know. I think mankind is affecting the climate, but whether it's affecting it a little bit or a lot, I think in reality we really just don't know.
Kirsty Wark: Thank you both very much indeed.