From Western disturbances to El Niño, climate change is affecting India’s food security Premium

Climate phenomena in India this year demonstrate complexity of precipitation system. Western disturbance, El Niño, and Indian Ocean Dipole (IOD) all affect monsoon, green water, and blue water, impacting food and water security. Central India's highlands are climate change hotspots, with water stress, declining monsoon, and increased intensity of rain events. Adaptations and alternative crop strategies can reduce vulnerability to El Niño, but new policies are needed to recharge aquifers and restore ecological flows.

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

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. Between July 5 and July 20, the affected area was estimated to be between 2,124 and 7,362 sq. km. The population affected was potentially more than 25 lakh.

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.

Soon after this 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.

Not all El Niño events have adverse effects on the southwest monsoon because the latter is driven by many ocean-atmosphere-land processes. But the relationship between the two entities has been changing over time. 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.