As Goa awaits the onset of the monsoons to bring relief from the oppressive summer heat, ominous dark clouds loom on the metaphorical horizon. Spelling trouble for the entire Western coast, studies have indicated that the Arabian Sea has begun warming at a faster rate since 1995.
Even more disconcerting are indications that warming of the Arabian Sea has been accompanied by a five-fold increase in the occurrence of cyclones, warmer winters and deficient rainfall, which all point to the alarming effects of climate change.
Research conducted by the National Institute of Oceanography and Central Marine Fisheries Research Institute, Kochi using data collated over a period of five decades has indicated that sea surface temperatures have begun to rise at an average of 0.014 degree Celsius per year, faster than the 0.08 degree Celsius recorded prior to 1995 in the Arabian Sea.
Warming of the Pacific and Indian oceans at a rapid rate has set alarm bells ringing within the global scientific community and governments. Global warming and human-induced climate change are the immediate threats to mankind and tropical regions are the most vulnerable to them, researchers have said. Global warming has different manifestations, such as increase in the number and severity of tropical cyclones, changing pattern of precipitation, melting of glaciers and associated sea level rise.
The average sea surface temperature of Arabian Sea is 28 degree Celsius. The research paper titled Response of the Arabian Sea to Global Warming and Associated Regional Climate Shift, has been authored by five researchers, S. Prasanna Kumar, Raj P. Roshin, Jayu Narvekar, P.K. Dinesh Kumar and E. Vivekanandan.
The study conducted by the five researchers have indicated that from 1960 to 1995, the increase in sea temperatures was steady but from 1995, there was a sudden increase in the pace of warming. “The Arabian Sea is experiencing a regional climate-shift after 1995, which is accompanied by a five-fold increase in the occurrence of most intense cyclones,” physical oceanographer and physicist at National Institute of Oceanography Prasanna Kumar explains.
Studies conducted by the researchers show that signs of this climate-shift are also perceptible over India such as progressively warmer winters, and decreased decadal monsoon rainfall. “The warmer winters are associated with a 16-fold decrease in the decadal wheat production after 1995, while the decreased decadal rainfall was accompanied by a decline of vegetation cover and increased occurrence of heat spells,” the research paper published in the science journal Marine Environmental Research said.
The research paper attributes the warming to increased CO2 emission. “It may be noted that the CO2 driven radiative forcing during 1995 and 2005 showed a 20% increase, the largest change for any decade in at least the last 200 years. The increase in the sea temperatures after 1995 can thus be called as the ocean response to external forcing by greenhouse gases,” Kumar said.