From El Niño to La Niña: Is respite finally in sight?

livemint.com:

The scorching summer that India just trudged past was yet another reminder of a rapidly warming Earth, with temperatures soaring to almost 50° Celsius in one of our longest heatwave spells. The country logged more than 40,000 suspected cases of heatstroke, with a death toll of over 100 people. But 2024 stands out for another reason: a shift in the Pacific Ocean’s see-saw of warm and cool water along the equator, a phenomenon that distorts weather around the globe.

An El Niño phase that began in mid-2023 gave Asia drier weather than usual, with weak rains witnessed in the early part of the monsoon. By end-May 2024, however, the India Meteorological Department (IMD) noted that this Pacific oscillation had turned neutral, and now it forecasts the likely development of its other extreme, La Niña, towards the end of August. The US National Oceanic and Atmospheric Administration has put a number to it.

It predicts a 66% chance of La Niña emerging during September to November. The way this year’s monsoon roared back this month from sparse to plentiful, though, makes one wonder if the awaited tilt has already occurred. Under the sun’s glare, oceanic water is always warm close to the surface around the equator, but the eastern end of an ocean can still be cooler than the other (and vice-versa).

Under usual conditions, the Pacific’s warm water moves east slowly along with the planet’s rotation. But equatorial trade winds can blow it west. In a neutral scenario, these forces balance each other.