In yet another indication of rising temperatures, data from the world's first Geothermal Climate Change Observatory in a low latitude area, located about 60 km from here, and different parts of the country has shown that earth in the region has became warmer by more than 1 degree Celsius during the past 100 years.
Established by CSIR-National Geophysical Research Institute at Choutuppal in Nalgonda district, the observatory is the second of its kind in the world and the first in low latitudes. It was set up to measure sub-surface temperature changes on annual-to-decadal timescales and cor-relate them with surface temperature changes being recorded at the same site. Two boreholes were drilled at depth of 21 metres and 210 metres in 2009 as temperature-depth profiles measured in boreholes contain records of changes in surface ground temperature over the past few centuries.
The temperature was measured at the depth of every three metres in the 210-metre deep borehole by a high precision instrument. It reflected the ground surface temperature changes inside the earth too as there was a tracking between surface and sub-surface temperature changes, Sukanta Roy, Principal Scientist and Project Leader, Heat Flow and Heat Production Studies, NGRI, told The Hindu . “We are trying to understand the signature of climate change inside the earth in a low latitude area,” he added.
With concerns being raised about the deleterious impact of global warming on ground water as also sea levels, the scientists from NGRI have begun gauging whether the Indian monsoon would have any influence on the temperature changes inside the earth. He said that to study the monsoon-related issues, India was the best place for a low altitude region.
Besides, Choutuppal, boreholes were drilled in more than 100 sites in South India, including Andhra Pradesh, Karnataka, Tamil Nadu and Kerala, besides 30 other places in the rest of the country. The results showed that the average warming of earth at all the sites was more than 1 degree C over the past 100-150 years.
He said another Geothermal Climate Change Observatory, located in Utah, USA, had found that the tracking of sub-surface and surface temperature changes was mainly influenced by solar radiation. The difference between the surface air temperature and ground surface temperature was only one degree. The data from Utah observatory revealed that it could be as high as 5 to 6 degrees. Dr. Roy said that if the temperatures continued to rise, it might have an effect on agriculture and groundwater.