Global warming impacting monsoon trend in India: Study

J Ramakrishnan
Thiruvananthapuram, Jan 26 (PTI) Increasing global
warming has had an adverse impact on the monsoon activity over
peninsular India in the last five decades resulting in decline
in number of monsoon depressions and weakening of the monsoon
current, according to a senior meteorologist.

The strength of low level monsoon winds through the
region had decreased by about 20 per cent during the last 50
years, P V Joseph, a former director of India Meteorological
Department (IMD), said.

The finding was that the sea surface temperature of the
equatorial central Indian Ocean has increased by about 1.5
degree Celsius, which was much higher than anywhere else in
the global tropics, he said.

"This phenomenon is feared to have had an adverse impact
on the Indian monsoon by creating an area of increasing
rainfall near the equator which would weaken the monsoon heat
engine (the vertical Monsoon Hadley Cell that drives the
monsoon circulation over the subcontinent)," Joseph said in a
paper presented at the 'National Workshop on Global Warming
and its effect on Kerala" here last week.

All-India average air temperature had also increased by
0.6 degree Celsius in the last century. This was comparable
to the global average.

The observed change in climate has been two ways --
decadal change (a few decades of increase followed by a few
decades of decrease) and long term trends, either decreasing
or increasing.

The annual number of monsoon depressions and the monsoon
rainfall of south Kerala had witnessed strong decreasing
trends. However, reason for this had to be studied in depth,
the paper said. PTI