A recent research report released by a team of researchers from Centre for Earth Sciences at the Indian Institute of Science, Bengaluru, established that 30% of rainfall received in the city has its origin in the Western Ghats.
The researchers developed a technique to determine the source and composition of rain in a place through isotopes of oxygen and hydrogen. The study found that in the three months that the Southwest monsoon lashes the subcontinent, evaporation from land masses of the Western Ghats is critical.
The Unesco recognised this 1,600 km-long ribbon of mountains declared as a world heritage site in 2012 and listed as one of the best examples of the monsoon systems on the planet. The Western Ghats are the water towers of peninsular India. An overwhelming 245 million people depend on these systems for their need of water.
Studies prove that rainfall is diminishing over the Western Ghats for the past 30 to 40 years. Between 1999 and 2005, there was almost 10% less annual rainfall. Its patterns, too, have shifted. The Southwest monsoon from June to July is found to have been decreasing while the post-monsoon rains of October and November have increased.
Decreased rainy daysHailing from the foothills of the Western Ghats, I had opportunities to watch the changing pattern of rains in the belt for the past 50 years. A more indecisive rainfall pattern prevails here currently. There is an increase in the rainfall volume over a shorter period of time. The rain that earlier fell over a few months may now occur within a span of a few days or weeks.
The decrease in the number of rainy days is already being felt and experts fear that it could affect the diversity of organisms. Instead of light steady rains over a long period, heavy rains over shorter periods of time can result in soil erosion and consequent infertility of the soil. Decline in the quantum of rainfall could lead to water scarcity.
The Western Ghats, being the primary catchment for most of the rivers in peninsular India, a reduction in rainfall has made many of the perennial streams seasonal. This has resulted in land-use alterations like paddy fields being converted into arecanut and banana plantations that increase the risk of flash flooding.
According to the Indian Meteorological Department's data, between 1951 and 2010, the annual and seasonal mean temperatures had increased significantly in all the six states of the Western Ghats: Gujarat, Maharashtra, Goa, Karnataka, Tamil Nadu and Kerala, although there is a great deal of each state that falls outside the mountain range, too.
Critical roleThough the critical role of the lush forests and towering hills of the Western Ghats in the strength of the rainfall in cities like Bengaluru is proved scientifically, the 2015 Forest Survey of India report had shown that a disheartening 173 sq km of forest land had reduced in the eight districts of Karnataka through which the mountain chain runs.
The apathy displayed by the governments towards the Madhav Gadgil and Kasturirangan reports on the Western Ghats shows how the answerable centres of power are least bothered about the secure future of its citizens.
In fact, the two reports were a unique opportunity for the government to find an answer to the problems of environmental annihilation rampant in the belt. Sadly, the Union government as well as the states have failed to act so far.
The previous UPA government as well as the present BJP government put on hold the execution of the recommendations of both the panels. While disputes between the Karnataka and Tamil Nadu governments over the sharing of the Cauvery and Kabini waters make headlines now, both of them could not behave responsibly by submitting their ecologically sensitive areas (ESA) list for implementation of the reports.
Politics, playing hands-in-glove with religious forces and wealthy farm owners in the catchments of the Western Ghats, to block the implementation of the Gadgil and Kasturirangan reports is worrying. This natural forest stretch from the mouth of Tapti in Dhule district of Maharashtra to Kanyakumari in Tamil Nadu is nature’s unique evolutionary laboratory still at work.
This mountain chain is critical for the air and water security of south India. Political commitment is indispensable to protect this gateway to monsoons and a hotspot of biodiversity.
(The writer teaches at Christ University, Bengaluru)