General Studies Paper 3

Context

• There has been a series of disruptive weather and climate phenomena in India this year, demonstrating the complexity of our precipitation system.

About

• There was the Western disturbance, which usually brings much-needed moisture from European seas to the western Himalaya and parts of northern India in the winter and spring.
• But this year, the Western disturbance lived up to its name and remained active late into the summer, snapping at the heels of the southwest monsoon.
• The widespread destruction of infrastructure and loss of life due to landslides and flooding in the western Himalaya and northern India raised concerns about the sustainability and resilience of our development projects in the mountains and floodplains.

An El Niño phase

• Climate-linked warming is likely to weaken winter precipitation from the Western disturbance and shift it to more intense rain events. If this happens later into the summer, its consequences will be of great concern.
• Moreover, then came evidence that an El Niño phase of the quasi-periodic El Niño Southern Oscillation (ENSO) — a phenomenon in the eastern and central tropical Pacific Ocean — was intensifying and likely to affect the southwest monsoon.
• When an El Niño affects the southwest monsoon, another ocean-atmosphere phenomenon in the Indian Ocean — called the positive-phase Indian Ocean Dipole (IOD) — could balance the consequences.
• Dynamic regression models have suggested that 65% of the inter-annual variability of the southwest monsoon, over many decades, can be attributed to the combined effects of ENSO and the IOD.

El Niño and food security

• Agriculture depends on two types of water — green water which is rain-fed soil moisture tapped by food and cash crops, eventually transpiring into the atmosphere and blue water which is the water in rivers, lakes, reservoirs, and groundwater.
• The latter is the basis for irrigation in agriculture, apart from drinking and industry use supply, and maintains ecological flows in rivers.
• The El Niño and other climate phenomena affect rainfed agriculture in many ways, from delaying the start of rains, and affecting sowing, to hot temperatures that may negatively influence plant growth and soil moisture.
• Despite investments in dams, reservoirs, and irrigation systems, around half of the cultivated area in India depends on green water, not blue water.
• Even in irrigated areas, many dominant crops require green water for different extents.
• Many staple crops like tur dal, soybean, groundnut, and maize also rely considerably on green water at this time.

The Response

• In terms of agriculture and food security, there is now an emphasis on reducing dependence on water-intensive crops, with millets being the crops of choice.
• Shifting to less water-intensive crops may reduce vulnerability of our food systems to phenomena like El Niño.
• There are several adaptations and alternative crop strategies available which include shifting to millets and alternative varieties of dominant cereals and advisories to farmers to switch to crops with shorter growing cycles.
• The government, both at the Centre and in the States, along with farmers, benefit from forecasts of phenomena like El Niño and their impact on the monsoon, and improvements in short-term weather forecasts and early warning systems for both intense rain and dry spells.
• Based on decades of experience, it is clear that alternative short-term and long-term management of our dams and reservoirs is required to reduce the risk of dam-based flood disasters and ecological damage to aquatic ecosystems.

Conclusion

• We should base our adaptation plans on the idea that current trends will continue. It’s possible that as warming increases, total rainfall in parts of India may increase but the share of extreme rain events may go up.