Monday, July 23, 2007

England under water: scientists confirm global warming link to increased rain

It's hard to explain to non-Brits the kind of rain we have been having recently. This month usually generates 35mm of rain in the entire month and last Friday we had 85mm of rain fall within a mere two hours. It's no exaggeration to say that the rain felt almost biblical in proportion. It was certainly on a scale of nothing that I personally had ever previously witnessed.

And compared to the Midlands we, here in London, are having it light. The flooding across the British Midlands has been going on for weeks now with entire families having to move out into temporary accommodation and insurance companies facing colossal claims from families whose entire house contents have been ruined in a matter of hours.

And now scientists are saying that this rainfall is directly linked to global warming.

More intense rainstorms across parts of the northern hemisphere are being generated by man-made global warming, the study has established for the first time ­ an effect which has long been predicted but never before proved.

The study's findings will be all the more dramatic for being disclosed as Britain struggles to recover from the phenomenal drenching of the past few days, during which more than a month's worth of rain fell in a few hours in some places, and floods forced thousands from their homes.

The "major rainfall event" of last Friday ­ fully predicted as such by the Met Office ­ has given the country a quite exceptional battering, with the Thames still rising. In Gloucester water levels had reached 34 feet, just 12 inches below flood defences ­ the same level as during the flood of 1947 ­ although a police spokesman said last night that the River Severn had stopped rising.

Last night vast areas of the country around Gloucestershire and Worcestershire were still inundated, large numbers of people in temporary accommodation, transport links were widely disrupted, and yet more householders were standing by to be flooded in their turn, in one of the biggest civil emergencies Britain has seen.

About 150,000 residents in Gloucestershire were left without drinking water when the Mythe Water Treatment Works in Tewkesbury became inoperable after flooding. Another 200,000 people are at risk of losing their supplies. The water shortages may last until Wednesday and 600 water tanks were being drafted to the area.

There is a terrible irony to people who have been forced to evacuate their homes due to flooding being told that there is a water shortage, but yet that is exactly what is happening here. It has also been noted that the frequency of these floods is increasing:

The Great Flood of July is all the more remarkable for following right on from the Great Flood of June, which caused similar havoc in northern towns such as Doncaster and Hull, after a similar series of astonishingly torrential downpours on 24 June.

Now whilst the new study does not definitely prove that such events are linked to man made climate change, it certainly supports the idea by showing that over the past few decades rainfall has increased across several areas "including the mid-latitudes of the northern hemisphere, and linking this directly, for the first time, to global warming caused by human emissions of greenhouse gases."

The study will be published on Wednesday but it's main findings are causing a stir and are being freely discussed:

One source familiar with the study's conclusions said: "What this does is establish for the first time that there is a distinct 'human fingerprint' in the changes in precipitation patterns ­ the increases in rainfall ­ observed in the northern hemisphere mid-latitudes, which includes Britain.

"That means, it is not just the climate's natural variability which has caused the increases, but there is a detectable human cause ­ climate change, caused by our greenhouse gas emissions. The 'human fingerprint' has been detected before in temperature rises, but never before in rainfall. So this is very significant.

"Some people would argue that you can't take a single event and pin that on climate change, but what happened in Britain last Friday fits quite easily with these conclusions. It does seem to have a certain resonance with what they're finding in this research."

It's very interesting that this new report is being published so soon after storms the likes of which no-one in Britain has ever seen before, and that the report is claiming that these same storms are directly linked to man made climate change. Because that is certainly the feeling of people on the street. Now I'm not suggesting that people are standing in newsagents up and down the country ringing their hands over man's involvement in climate change, but there is certainly an acceptance that what is occurring has not occurred before and that a change of some kind is taking place.

The human fingerprint is detected by making computer simulations of the recent past climate, with and without emissions of greenhouse gases ­ and then comparing the results with what has actually been observed in the real world.

In Dr Stott's research, and in the study to be published on Wednesday, the observed rises in temperature and rainfall could be clearly accounted for by the scenario in which emissions were prominent.

The conclusions of the new rainfall study are regarded as all the more robust as they are the joint work of several major national climate research bodies, led by Environment Canada, with each using its own supercomputer climate model.

Global warming is likely to lead to higher rainfall because a warming atmosphere contains more water vapour and more energy. Since climate prediction began 20 years ago, heavier rainfall over Britain has been a consistent theme.

Like many people I always associated global warming with hotter summers and never for a moment thought that it would result in massive flooding. But there are many northern towns in Britain which today show just what such a scenario will mean for people if the scientists are right.

There will be some who scoff at the scientists findings, but no-one who witnessed the rain that hit Britain last Friday will argue that something very strange occurred here, certainly rain with an intensity that none of us had ever previously witnessed.

As my roofer said when replacing tiles, "In 37 years of driving through London, I've never had to pull over before because I couldn't see the road in front of me because of the rain".

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1 comment:

Unknown said...

scientists confirm global warming link to increased rain

The original version of the article was: "Scientists confirm global warming and Dick Cheney links to increased rain."