EXTREME EVENTS OF CLIMATE CHANGE

Recently, Research has shown that global warming, triggered by Climate Change, increases the fluctuations in the monsoon, resulting in both long dry periods and short spells of heavy rains.
The Year 2022 has seen the second highest extreme events since 1902. An alarming case as incidents of floods and droughtshave increased.
A shift in the track of monsoon systems has been seen such as low pressure and depression travelling south of their position and flash floods.
Monsoon depression originally refers to a low-pressure system affecting the North Indian Ocean and the Bay of Bengal in summer. It encompasses a relatively large area and the diameter of closed isobar can be as wide as 1000 km.
Madhya Pradesh, Gujarat, Rajasthan and parts of Maharashtra have recorded excess rainfall in 2022, in contrast, West Bengal, Jharkhand and Bihar did not receive normal rains.
August 2022 too saw two back-to-back depressions forming in the Bay of Bengal and traveling across Central India.
While summer monsoon rainfall each year is unique, there has been a large regional and temporal variability in rainfall in 2022.

Causes:

Persistence of intense La Nina conditions, the abnormal warming of East Indian Ocean, negative Indian Ocean Dipole (IOD), southward movement of most of the monsoon depressions and lows and pre-monsoon heating over the Himalayan region and melting glaciers.
IOD is defined by the difference in sea surface temperature between two areas (or poles, hence a dipole) – a western pole in the Arabian Sea (western Indian Ocean) and an eastern pole in the eastern Indian Ocean south of Indonesia.
The IOD affects the climate of Australia and other countries that surround the Indian Ocean Basin, and is a significant contributor to rainfall variability in this region.

Impacts:

KhOne of the major impacts of changes in track of monsoon systems can be seen on kharif crops, particularly rice production. They form a significant share of more than 50% of total food grain production during this period.
The fall in Kharif output may keep rice prices at elevated levels.
Bihar, West Bengal and Uttar Pradesh, which account for a third of the country’s total rice production, have been highly deficit despite an active monsoon current in July and August.
These uneven distribution rains may impact the quality of the grain as well as the nutrition value may vary.
According to a study, ‘Climate change, the monsoon, and rice yield in India’, very high temperatures (> 35°C) induce heat stress and affect plant physiological processes, leading to spikelet sterility, non-viable pollen and reduced grain quality.
Monsoon rainfall became less frequent but more intense in India during the latter half of the 20th century.
Scientists and food experts believe that a better rainfall scenario could have helped increase the harvest.
However, India’s hundreds of millions of rice producers and consumers are being affected negatively with these unprecedented changes which are also raising concerns over food security.

Way Forward

India needs to invest more resources in better prediction of Monsoon forecast in order to achieve reliability and sustainability.
With a warming climate, more moisture will be held in the atmosphere, leading to heavier rainfall, consequently, inter-annual variability of the monsoon will increase in future. The country needs to prepare for this change.

SOURCE: THE HINDU,THE ECONOMIC TIMES,MINT

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