Mercury rising

Siliguri, Nov. 6: The mercury is rising in Darjeeling.

In one of the most striking revelations of recent times, the Queen of Hills has shown an increase of more than one degree Celsius in its mean annual temperature in the last 100 years.

“This is an alarming trend, given that the average rise in the mean annual temperature of the world in less than one degree Celsius, with developing countries registering a much smaller figure,” said Subir Sarkar, the in-charge of North Bengal University weather station.

Hundred years ago, the mean annual temperature of the hill town stood at 13.45 degrees Celsius. “At present it is 14.5,” Sarkar said. The rise has made both the summers and winters a wee bit warmer.

The rise in the hills is twice that of the plains. “In the plains of north Bengal, the average rise is 0.5 degrees,” Sarkar said.

According to data available with the weather station, the rise in Jalpaiguri has been from 23.9 degrees to 24.45 degrees, for Cooch Behar 23.90 to 24.50 and for Malda 25.75 to 26.20 degrees Celsius. “Balurghat has recorded a rise of 0.40 degrees Celsius,” Sarkar said.

While global warming is said to be the main and obvious reason for the rise in the mercury level in the hill town, a number of local factors, too, have contributed to it.

“Mindless urbanisation and depletion of forest cover are two important local reasons for the rise in the temperature,” Sarkar said. “Due to Darjeeling’s precarious geographical location, the effect of even slight variations in the natural environment becomes more pronounced and produces far-reaching effects.”

One of the immediate effects the warming will have is that on the soil condition. “It causes the soil to lose moisture rapidly,” Sarkar said.

It is feared that Siliguri, which has witnessed massive urbanisation (characterised by a population growth of about 49 per cent and vehicular growth of 79 per cent), may also have shown a considerable increase in the mean temperature, but there is no data available to corroborate the assumption. “Since we do not have the records of Siliguri’s temperature variation, nothing can be said about its trend,” Sarkar said.

Relative to the period (1860-1900), global temperatures of both land and sea have increased by 0.75 degrees. Based on estimates by Nasa’s Goddard Institute for space studies, 2005 was the warmest year since the late 1800s, when reliable instrumental measurements became available.