Historically, strong El Nino events have had catastrophic outcomes including droughts across the world. In 1768–71, severe droughts, especially in Bengal, led to 10 million deaths, shaking the very foundations of the British Empire.
Spring means new growth, but in South India it brings more heat. After the fourth warmest February on record, the hottest in a century in India, forecasters warn about an unusually hot summer this year due to the El Nino effect in India and elsewhere (KA Shaji)
As many houses in South India are adorned with colourful kolams and thoranams for the spring festival of Ugadi (beginning of the year) on Wednesday, forecasters are seeing a harsh summer ahead in 2023 due to the El Nino effect.
Vernal equinox or the beginning of spring is the moment when the sun crosses the celestial equator, an imaginary line that runs through the sky right above the equator exactly between the hemispheres. That happened at 2.54 am Indian time on Tuesday.
“Once the sun’s vertical rays approach the equator, the maximum temperature will rise beginning today [Tuesday],” Prof S Abhilash, director of the Advanced Centre for Atmospheric Radar Research at Cochin University of Science and Technology (CUSAT), told South First on Tuesday.
Spring means new growth, but in South India, it brings more heat. After the fourth warmest February on record, the hottest in a century in India, forecasters warn about an unusually hot summer in 2023 due to the El Nino effect in India and elsewhere. “Real heat issues will emerge,” Abhilash said.
Over the past three years, a phenomenon called La Nina — in which the tropical Pacific has cooler than average sea-surface temperatures — has cooled down the global average temperature. That phase has ended. Now it is a neutral phase, but there is an El Nino event forecast for later in 2023.
Though the event is still not visible, there are some small signs. On 18 March, scientists observed a sea surface temperature (SST) anomaly of 4 degrees C off the coast of Peru.
Anomalies denote the departure of a measurement from its long-period average. “Looks (like) a typical Canonical El Nino event. We need to keep monitoring its evolution closely,” a leading Indian monsoon scientist tweeted on Monday.
“El Nino” denotes unusually warm waters off the coast of Peru close to Christmas, causing weather changes across the Pacific basin and elsewhere. In Spanish, Niño means boy and refers to infant Jesus.
Tropical Pacific weather conditions oscillate irregularly between warm El Nino and cool “La Nina” (“the girl” in Spanish) phases. Canonical or conventional El Nino is associated with anomalous warming in the eastern equatorial Pacific, El Nino Modoki with warming in the central tropical Pacific.
On 18 March, scientists observed a sea surface temperature anomaly of 4 degrees C off the coast of Peru (Representative image, KA Shaji)
An El Nino can raise the earth’s surface temperatures by a few tenths of a degree, still significant in a warming globe. As Adam H Sobel, an atmospheric scientist and professor at Columbia University wrote in the Time magazine:
“Since our average temperature has already increased by 1.2 C since pre-industrial times, a sufficiently major El Nino event could even push the planet, temporarily, past 1.5 C warming.” Models project robust differences in regional climate between present-day and global warming of 1.5°C, considered a point where we must strive to stop warming.
Historically, strong El Nino events have had catastrophic outcomes including droughts in India and the rest of the world, through teleconnections or large-scale air pressure and circulation patterns.
Observers in South India have meticulously recorded El Nino events after 1734, and instrument observations are available from 1776.
Richard Grove, the late Sussex University environmental historian and professor, has written extensively about the impact of El Nino from Australia to Europe and the Caribbean. During the French Revolution years between 1789 and 1792, for instance, Europe witnessed unusual weather events, he notes.
In 1768–71, severe droughts, especially in Bengal, led to 10 million deaths, shaking the very foundations of the British Empire.
East India Company surgeon — and accomplished botanist — William Roxburgh, who was posted in the Madras Presidency, recorded the failure of the South Asian monsoon between 1789 and 1792, with the most severe failure in 1790.
The human history of El Nino has fascinated many scholars.
Historian Mike Davis suggests in his book Late Victorian Holocausts that at least three great famines in the late 19th century were connected to El Nino, fuelled by European capitalism, and colonialism. India witnessed severe droughts in 1876–78, 1896–97, and 1899–1900, while Peru had bumper crops.
Many major droughts in the 20th century have been attributed to the El Nino effect as scientists established a clear link.
Recent history of the monsoon in India had shown a weakening link with El Nino since the 1970s, but the connection seems to have been restored by 2000. With global warming, the impact of El Nino in India and elsewhere is likely to increase as scientists note.
We will get to hear more from them in the coming weeks.
(Max Martin is a geographer researching marine weather, climate change and people’s responses. He has reported science for leading publications and won the Prem Bhatia award for environmental journalism. He lives in Bengaluru)
