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Heatwave: is global warming to blame?
« on: 2003-10-07 14:31:14 » |
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Following the discussion at http://virus.lucifer.com/bbs/index.php?board=4;action=display;threadid=25646;start=0;boardseen=1 I thought this might be relevant to some of the points of detail:
http://www.spiked-online.com/Articles/00000006DEC3.htm
by Philip Stott
I am writing this in Gravesend, Kent, the town where Princess Pocahontas is buried and which last Sunday boasted the so-called UK record temperature of 38.1 degrees Celsius (101 degrees Fahrenheit).
I say 'so-called', because comparing modern temperature measurements with older measurements can be misleading. Measuring stations where temperatures have been recorded over many years may no longer have the same local environment, due to increased urbanisation and the urban 'heat-island' effect (and Gravesend is presently experiencing a massive exposure of reflective white chalk during the construction of the new Ebbsfleet railway station).
Moreover, modern thermistor- and thyristor- based instruments react very quickly, and are likely to record more extreme transitory temperature highs and lows than the older mercury-in-glass thermometers. So current temperature measurements are probably exaggerated relative to the older measurements, such as the 36.1 C recorded for Camden Square, London, in 1911.
Yet there has been a desperate desire to see our heatwave - and the summer fires in Spain and Portugal - as confirmation that we are in the grip of human-induced 'global warming' (1). Many in the environmental movement are calling for draconian international action, despite concerns that this will increase hardship and misery, particularly in the developing world (2).
But are the current temperatures and fires exceptional? If you lived in late-nineteenth century Spain, you would not think so. In Seville on 4 August 1881, temperatures soared to a siesta-searing 50 C (122 F) (3). Now that is a flaming flamenco. And our summer would have been familiar to much of Europe during what we call the Medieval Warm Period, between 1100 and 1300 (4) - when frosts in May were unknown and summer temperatures were on average 0.7 to 1.6 degrees C higher than today (5).
In addition, looking at the pattern of highest recorded temperatures by continent, there is no obvious trend. The high for Australia was in 1889, for Latin America in 1905, for North America in 1922, for Asia in 1942, and for Antarctica in 1974. At most, these may reflect a staggered emergence from what we call the Little Ice Age, which ended around 1880. It is worth remembering that1805 to1820 were the coldest years for many centuries, and 1816 is notorious as 'the year without a summer' (6). Who would wish to return to that?
So what trends can be discerned? If you examine the past 250 years (7), there was intermittent severe cold and some warming towards the end of the Little Ice Age, with a more general warming to about 1946. This was followed by a recession to colder times until the 1970s, when we began another small increase in temperature. Overall, temperatures have risen by a mere 0.6 degrees C over the past 150 years - which is unexceptional given that we are moving away from a Little Ice Age.
Our present heatwave is also far from strange. The British Isles are a constant battleground between competing pressure systems, originating in the Atlantic, the Arctic, Russia, and, more occasionally, North Africa. Whenever high pressure forces its way over Europe from Africa, we simmer in the sun. In the now-legendary summer of 1976, red sand from the Sahara made parked cars look like they were suffering from automotive measles. And the heat of 1976 was far more persistent than today's, with over 15 consecutive days above 32 C, and an intense accompanying drought.
According to which pressure system is dominant, we can experience floods, or drought and fire, or, on too many occasions for the British holiday industry, cloudy coolness and damp dullness on grey English beaches. And sometimes we can suffer cold easterly winds from off the Urals.
Likewise, vivid as the Mediterranean fires may seem on TV, they are nothing unusual. The fires in Italy, for example, are average for the season, although those in Portugal have been more severe this year. Mediterranean vegetation is naturally fire-prone and requires careful management by grazing and controlled burns. You must always fight 'fire with fire' to ensure that there is no build-up of tinder-dry fuels. Where this practice is neglected, it can result in damaging conflagrations when drought arrives. The carelessly dropped cigarette will then cause mayhem.
For the past 15 years, green pressure groups with vested interests have worked hard to persuade us that all such climatic phenomena are evidence of human-induced warming. But we must be wary of trying to link naturally varying weather events like fires and floods to simplistic ideas like 'global warming'. As the World Meteorological Organisation (WMO) pointed out earlier in August, 'We need more than just one or two events' ( 8 ). After all, it remains impossible to forecast weather more than 10 days in advance!
And 'global warming' and 'climate change' should never be confused. Climate change is a truism; it happens all the time. It would be extraordinary if climate were not changing. 'Global warming', by contrast, is a 1990s apocalyptic construct that climate change is primarily driven by human emissions of so-called 'greenhouse gases', like carbon dioxide and methane, and that these will cause a massive rise in temperature by as much as six degrees C by the year 2100. It is argued that we can only produce a 'sustainable climate' by cutting down on these emissions.
But climate, and our weather, is governed by thousands of interacting factors, from erupting volcanoes to the cycles of the sun. Sorting these out, and predicting what might ultimately happen, is like trying to control a million drunks on a Saturday evening, all chaos and non-linear activity.
And the core problem is that the very concept of a 'sustainable' climate does not make sense. Even if we junked every car, closed down every factory, and shut down every power station, climate would still change, and we would still suffer heatwaves and ice ages. Such actions might even precipitate us into another ice age, and, as history illustrates, cold periods are normally worse than warm, both for humans and for wildlife.
This is the fallacy of 'global warming'. King Canute demonstrated to his followers that he could not control the waves. A wise modern king would be telling us that there is no way we can manage climate predictably.
If anything, human actions have increased the complexity of climate. Natural climate drivers include volcanoes, vegetation, the oceans and ocean currents, clouds and water vapour, naturally emitted 'greenhouse gases', the Earth's cycles and wobbles, solar variations, atmospheric dust, space debris, and a range of other factors difficult to interpret, such as the altering magnetism of the Earth. To this, humans have added not just emissions of 'greenhouse gases', which might or might not be warming the atmosphere, but particles like dust and soot, some of which cool.
Moreover, through our cities and agriculture we are constantly varying the surface reflectivity of the Earth, as with the exposure of white chalk at Gravesend. But unfortunately we know next to nothing about most of these factors, including obvious ones like water vapour, the most important 'greenhouse gas' of all, and clouds.
The sooner we admit that we have no predictable control over climate, the better. This is what is wrong with the ill-fated Kyoto Protocol on climate change. Not only are the national targets it set for cutting 'greenhouse gas' emissions impossible in the face of economic growth, particularly in the developing world like China and India - they would not work in pure climate terms. Fiddling at the edges of this mighty Wurlitzer of a system will accomplish nothing and may make things worse.
But the real human danger of Kyoto is that aid finance is being deflected from much more practical ways of improving environmental performance and welfare, especially in developing countries. While billions are being squandered on a quixotic climatic adventure, millions die for want of clean water, sufficient food, basic medicines and a reliable modern energy supply.
The way to cope with climate extremes, hot or cold, real or imaginary, is to maintain strong flexible economies that can adapt to change, whether this change is cracking Gravesend paving stones or freezing bread indoors, as happened in 1309-10. And remember, in the UK, a little warming will be good for us. We may again compete with the French in producing fine wines, just like we did in the Medieval Warm Period.
Philip Stott is Professor Emeritus of Biogeography at the University of London and he is a member of the Advisory Forum of the Scientific Alliance.
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