Frequent marine heatwaves in Indian Ocean disrupt India’s monsoon pattern 

News: A phenomenon called Marine heat waves (MHW) have increased significantly in the past few decades in the Indian Ocean region. This is also impacting the Indian monsoon. 

What are marine heatwaves and why they occur? 

These are periods of increased temperatures over seas and oceans.  

They are caused by an increase in the heat content of oceans, especially in the upper layers.

Marine heat waves are one of the major result of human-induced global warming, as around 90% of the warming caused by greenhouse gas emissions is absorbed by the oceans. 

What is the impact on the oceans? 

These events cause habitat destruction due to coral bleaching, seagrass destruction and loss of kelp forests, affecting the fisheries sector adversely. 

An underwater survey showed 85% of corals in the Gulf of Mannar near the Tamil Nadu coast got bleached after the marine heatwave in 2020. 

How are they impacting the Indian monsoon? 

The recent increase in marine heat waves in the Indian Ocean was due to rapid warming and strong El Niño events.  

In the Indian Ocean, the worst-affected area was its western part and northern Bay of Bengal. This reduces the monsoon rainfall over central India while increasing rainfall over the southern peninsular area. 

Climate model projections suggest further warming of the Indian Ocean in the future, which will very likely intensify the marine heatwaves and their impact on the monsoon rainfall. 

What is the way forward? 

It is important to update current weather models to skilfully predict the challenges presented by a warming world and also enhance ocean observational arrays to monitor these events accurately. 

Source: This post is based on the article “Frequent marine heatwaves in Indian Ocean disrupt India’s monsoon pattern” published in Down to earth on 4th Feb 2022.