Five-fold rise in frequency of 'intense' cyclones: Study

The frequency of "intense" cyclones in Arabian Sea has increased five-fold over a period of 12 years due to sea warming, according to a new study. "Global warming has resulted in disruption of natural decadal cycle in the sea surface temperature (SST) of Arabian Sea after 1995," a research study by Goa-based National Institute of Oceanography (NIO) said. Due to this, there was a five-fold rise in frequency of intense cyclones between 1995 and 2007 when compared to the previous 25 years (1970-1995), the research paper said. The effects of this climate-shift are also perceptible over the adjacent landmass as it has led to warmer winters and decreased decadal monsoon rainfall, it said. "The Indian summer monsoon is driven by the land-ocean thermal contrast and a warmer ocean would weaken the summer monsoon," NIO's Prasanna, who contributed significantly to the research, said. "Hence, the negative decadal anomaly in the all-India summer monsoon rainfall during the late 1990s appears to be linked to weakening of land-ocean thermal-gradient under the secular warming of the Arabian Sea," he added. The study points out that it is not just the frequency but also the intensity of cyclones that has increased in the recent years.