There has been a disturbance in the Arabian Sea’s surface temperatures natural decadal cycle since 1995 and climate change may be to blame. A paper titled “Response of the Arabian Sea to global warming and associated regional climate shift” published in the journal ScienceDirect explores the effects of climate change on sea surface temperatures (SST), as well as other climate shifts.
The SST has been rising since 1904 to 1994 (approximately 0.5 °C) with a natural decadal cycle, but since 1995, it has increased steadily with no cycle. The natural decadal cycle is related to the solar irradiance cycle but since 2000 solar activity has declined yet SST continued to rise. This led the authors to suspect that the rise in SST is due to global warming. When examining the correlation between rising atmospheric CO2 concentrations and SST, there was an evident relationship between 1960 and 2006.
Other changes around the Arabian Sea are believed to be a result of rising temperatures. The intensity and number of cyclones has risen in the past twelve years (from 1995 to 2007). Also, air temperatures over India, during February, have rapidly increased an additional 1.5 °C since 1995. This is resulting in a decrease in wheat yield, since it is a winter crop. There has been a 4.5% decline in kernel weight for every 1 °C increase in temperature.
An obvious question remains; why is the Arabian Sea just showing the effects of climate change since 1995? This is due to the fact that a strong wind-driven upwelling brings cooler water to the surface, for example, the temperatures of the upwelling water near Somalia ranges from 17 to 22 °C. This upwelling has maintained the natural decade cycle, but since 1995 and 2006, carbon dioxide drive radiative forcing has increased 20% causing temperature’s to rise. Upwelling-driven cooling can no longer compensate this increase in temperature. This resulted in a steady increase in SST.
Rising temperatures due to climate change evidently caused the disruption of the natural decadal cycle in the Arabian Sea. The reason for the cycle not being affected until 1995 is due to the wind-driven upwelling masking the effects. The affecting SST rising temperatures have caused other changes as well, such as an increase in cyclone intensity and occurrences along with affecting crop yield. Many of the effects of rising SST are new and other further effects are unknown. Further study should be done on the food security within the region, since temperatures are expected to rise.
References:
Kumar, Prasanna, Raj Roshin, Jayu Narvekar, Dinesh Kumar, and E. Vivekanandan. "ScienceDirect - Marine Environmental Research : Response of the Arabian Sea to global warming and associated regional climate shift." ScienceDirect - Home. 5 Dec. 2009. Web. 14 Oct. 2009.
is there a possibility that the rising SST is not due to climate change, but another factor?
ReplyDelete