Under a fingernail moon at Sassoon Docks, Parumati Mangela, a fisherwoman, sat on her haunches, grimacing. Something strange is happening over the Arabian Sea, she said: “The sky is getting hot more and more,” perhaps because something has angered the goddess Lakshmi. As Ms. Mangela rounded up village women to pray at the water’s edge, state fisheries scientists were tracking worrying changes deep below, where in the last half century average surface temperatures have risen three-tenths of a degree Celsius, or half a degree Fahrenheit. This warming is driving familiar species into cooler waters, they say, replaced by species traditionally found hundreds of miles to the south, like Indian mackerel and oil sardines. At the climate talks in Paris, India ’s negotiators have staked out an adamant position: While India is vulnerable to global warming , raising a vast population out of poverty remains the national priority. […]