Global warming causes the sea level to rise every year. But researchers studying the seas around India have noted a paradox. From 1993 to 2003 the North Indian Ocean (NIO) sea level fell even when the global temperature soared. After which in 2004, sea levels began an unprecedented, accelerated spike till 2014. The scientist says this decadal swing is a phenomenon unique to the NIO as they have never been observed in either the Pacific or Atlantic oceans. In spite of the rapid, rise in temperatures, there are assumptions that the coming decades will see another fall in sea levels. More details please?
Mr. Ravichandran, the lead author of National centre for Antarctic and Ocean Research, and his colleagues relied on satellite observations and a global network of floats, which log temperature and salinity, to arrive at their findings. According to this the NIO went down about 0.3 mm a year and from 2004 gained about 6 mm annually. When temperature and sea level trends in the NIO were mathematically separated out from the other oceans, the fall was even more dramatic: nearly 3 mm per year and the Arabian Sea cooling off rapidly at 4 mm per year. What causes the fall?
Sea levels rises, when atmospheric heat causes water to expand and because of phenomenon like melting of ice sheets and glaciers. In the case of NIO, 70% of its warming could be explained by expansion. The NIO, Unlike the Pacific and Atlantic, is hemmed by the Arabian Sea, the Bay of Bengal and part of the Indian Ocean on all sides except for an outlet on the southern side. This influenced the rate at which heat was absorbed and flushed out from within. The change in the direction of wind flows, which welled warm water on the Indian Ocean surface also probably influenced sea level patterns. The wind flows changes directions every decade. Do all scientists believe this to be true?
A Previous study that measured ocean heights based on traditional tide gauges found that NIO, like the rest of the world’s seas was continuously rising between 1993 and 200. But Intergovernmental Panel on Climate Change reports concluded that unabated greenhouse gas emissions into the atmosphere would cause oceans to rise every year. But there would also be years during which some seas could register a fall.