Wednesday, July 30, 2008

Is world's wettest place getting drier?

By Alastair Lawson
BBC News, Meghalaya

Deforestation in Meghalaya
It's argued that deforestation has made climate change worse

The town of Cherrapunjee, in the north-eastern Indian state of Meghalaya, is reputed to be the wettest place in the world.

But there are signs that its weather patterns may be being hit by global climate change.

"Not without reason has Cherrapunjee achieved fame as being the place with the heaviest rainfall on earth," wrote German missionary Christopher Becker more than 100 years ago.

"One must experience it to have an idea of the immense quantity of rain which comes down from the skies, at times day and night without a stop. It is enough to go a few steps from the house to be drenched from head to foot. An umbrella serves no purpose."

Late monsoon

But according to Cherrapunjee's most renowned weather-watcher, Denis Rayen, the climate of the town is changing fast.

Map and graphic

"In the days of the Raj, the British used to come here to the the Khasi hills to escape the heat - we are 4,823ft (1,484m) above sea level," he says.

"But today I am not sure they would be able to do that, because it is getting a lot hotter here and the monsoon is arriving later."

Official figures compiled by the Indian Meteorological Office in the nearby city of Guwahati back up Mr Rayen's arguments that north-east India as a whole is getting hotter.

"The average temperature for Guwahati at this time of the year should be around 32C - but this year the temperature has been as high as 38C," said weather expert Harendas Das.

Denis Rayan explains climate change in Cherrapunjee

"It's too early yet to say precisely what is happening, but the evidence suggests that higher temperatures mean the whole area is experiencing less rainfall."

Figures compiled by Mr Rayen show that Cherrapunjee may struggle to maintain its position as the world's wettest place. Rainfall figures for 2005 and 2006 were below average.

"The average rainfall at Cherrapunjee during the last 35 years has been 11,952mm (470ins) and there were several years when it was substantially more than this," he says.

In 1974 it rained 24,555mm (967ins) - which Mr Rayen says is "the highest recorded rainfall in any one place in any one year".

On 16 June, 1995, it rained a record-breaking 1,563mm (61.53ins) over a 24 hour period.

"But in 2005 and 2006 our yearly rainfall was well below the average. We could well be witnessing a severe change in our climatic conditions because of global warming."

Waterfall at Cherrapunjee
In the monsoon, Cherrapunjee's waterfalls become raging torrents

While the annual rainfall for 2007 was back to normal, Mr Rayen argues that the "pattern of delivery" of Cherrapunjee's rainfall is changing. In previous years, 98% of the area's rainfall was between March to October.

This year the rains did not arrive until June, and the reason for that he says could be man-made.

"During the last few years, I have seen the forests vanish in front of my eyes," said Mr Rayen.

"A combination of global warming and intensive deforestation is taking a heavy toll in this, one of the most beautiful areas of India.

"Because it now rains heavily over a shorter time period, crops are destroyed and there is intensive soil erosion. The lack of woodland means that the water flows faster from Meghalaya into the Bangladesh delta, only 400km (249 miles) away."

Mr Das says that parts of Meghalaya are "at risk from desertification" because of a combination of increasing urbanisation and industrialisation on the one hand and deforestation and shortages of ground water on the other.

"Because the capacity of the soil to hold water is lost, there is a real possibility that the wettest place in the earth may soon be facing water shortages," he says.

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