Date: 19/09/2022

Relevance: GS-3: Conservation, environmental pollution and degradation, environmental impact assessment.

Key Phrases: Climate Change, Food Security, El Nino, La Nina, El Nino-Southern Oscillation (ENSO), Indian Ocean Dipole.

Context:

• Monsoon in India has undergone several changes over the years, especially on account of climate change.
• Let us discuss the complexities involved in Monsoon variability in India.

Background

• A shift in the track of monsoon systems, like low pressure and depression traveling south of their position and flash floods are a result of this change.
• These changes spell intense and frequent extreme unprecedented weather events over the places which once struggled to record even normal monsoon rains.
• With this looming threat having a bearing on food security, it is only a matter of time before it has socio-economic impact.

Complexity in Monsoon variability

• It has been very complex to understand the rainfall variability and how monsoon patterns have been behaving of late, especially this year.
• This challenging situation calls for a lot more research -
  • 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 is melting glaciers.

Indian Meteorological Department

• The Indian Meteorological Department (IMD) has sighted that 2022 has seen the second highest extreme events since 1902.
• Incidents of floods and droughts have increased, there is more evidence coming our way on how global warming has been impacting the Indian monsoon.
• Most of the monsoon weather systems have been traveling across central parts of the country, changing the area of rainfall. Climate change is definitely behind these changes.

How climate change impacts summer monsoon rainfall

• Places that once recorded excess rainfall are today rainfall deficit
  1. It is complex to understand the rainfall variability and how monsoon patterns have been behaving of late, particularly this year.
  2. Alarming increase in floods and droughts provides direct evidence of how global warming has been impacting the Indian monsoon.
  3. Madhya Pradesh, Gujarat, Rajasthan and parts of Maharashtra have recorded excess rainfall this year
  4. In contrast, West Bengal, Jharkhand and Bihar did not receive normal rains.
  5. Back-to-back active monsoon systems in the Bay of Bengal in July led to excess rainfall to the tune of 8% — actual rainfall recorded was 472.8 mm as against the normal of 437.2 mm
  6. August too saw two back-to-back depressions forming in the Bay of Bengal and traveling across Central India
  7. While summer monsoon rainfall each year is unique, there has been a large regional and temporal variability in rainfall this year.
  8. There is evidence that global warming increases the fluctuations in the monsoon, resulting in both long dry periods and short spells of heavy rains

Excess and deficit

• Usually, monsoon systems move across Northwest India giving rains over the region there.
• Experts believe that these changes would continue to propel extreme weather events over the entire South Asian region which has been reporting a series of extreme weather events.
• While Bangladesh, Pakistan and India have battled severe floods, China is reeling under massive drought conditions.
• Slow onsets can still be taken care of through adaptation and resilience ideas but these kinds of big events are very difficult to cope with.
• That is where the main issue lies as the country would then have to divert development money to climate finance to combat climate change.
• After a weak onset, monsoon went into a lull and so no thumping activity was seen in Kerala and adjoining parts of Karnataka.
• By June, monsoon had reached the plains but the onset was not a strong one. This resulted in West Bengal, Jharkhand and Bihar not receiving normal rains.
• Back-to-back active monsoon systems in the Bay of Bengal in July led to excess rainfall to the tune of 8% — actual rainfall recorded was 472.8 mm as against the normal of 437.2 mm.
• August too saw two back-to-back depressions forming in the Bay of Bengal and traveling across Central India.
• These intense systems in quick succession kept the monsoon trough well south of its normal position for most of August.

Rice production

• Monsoon each year is unique, but we did see a large regional and temporal variability in rainfall this year.
• Global warming increases the fluctuations in the monsoon, resulting in both long dry periods and short spells of heavy rains.
• This year, the monsoon was potentially influenced by La Nina also — the cooler than usual Pacific conditions.
• One 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.
• Arrival of monsoon and whether onset would be strong or weak will always continue to dodge us.
• Due to southward movement of majors, all main monsoon low pressure areas and depressions, rice producing States such as West Bengal, Bihar, Jharkhand and east Uttar Pradesh have been deficit by large margins.
• This would straight away have an impact on the quantity as well as the quality of the crop.
• 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 along with increasing temperatures and humidity give rise to pest attacks and diseases.
• This will, in turn, impact the quality of the grain as well as the nutrition value may vary.

Recent 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.
• Drought, on the other hand, reduces plant transpiration rates and may result in leaf rolling and drying, reduction in leaf expansion rates and plant biomass, immobilization of solutes and increased heat stress of leaves.
• 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.

Source: The Hindu

Mains Question:

Q. Research shows that global warming increases the fluctuations in the monsoon, resulting in both long dry periods and short spells of heavy rains. Comment. [150 Words].