Oceans Great Dying 2.0

Oceans Great Dying 2.0

Subject: Environment

Section: Climate Change

Context: Scientists have found the warming up of the oceans fundamentally disrupts the climate cycle.

Concept:

Marine Heatwaves

• The term marine heatwaves were coined for the first time only in 2011. This was after certain pockets of Western Australia experienced abnormally high sea surface temperatures, exceeding 3°C above average.
• These heat waves often accompany El Niño events in the Pacific Ocean. Other factors such as increased warming and weak winds also contribute to its formation.
• They seem to have picked up the pace by 15 per cent per decade from 1990 to 2013 due to human-driven activities.
• The impacts are more pronounced in the tropical oceansdue to surface winds that have intensified since the 1900s.
• At the same time, by reaching deep into the ocean, the acceleration could boost the storage of heat in the depths, helping slow the warming on land.
• The Indian Ocean, in particular, has emerged as the biggest victim of climate change than the Atlantic or Pacific as Indian Ocean holds warmer waters.
• From 1901 to 2012, the western Indian Ocean warmed up by 1.28°C against an increase of 0.78°C recorded in other parts of the Indian Ocean. The surface waters of the Bay of Bengal stay largely above 28°C.
• High Ocean temperatures are changing ocean currents and Scientists suspect that they could be fuelling cyclones, too.
• Between 2001 and 2019, the Arabian Sea recorded a 52 per cent increase in the number of cyclones. Very severe cyclones have increased by 150 per cent. The recent example isthe unusual behaviour of the 2020 Amphan super cyclone.

To know about Marine Heatwaves, refer: https://optimizeias.com/marine-heatwave-fuelled-super-cyclone-amphan/  and https://optimizeias.com/frequent-marine-heatwaves-in-indian-ocean-disrupt-indias-monsoon-patterns/