- 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.
- 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.
- 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.
- 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