What happens in India doesn't stay in India. Why this deadly heat wave has a wide reach

The persistent heat wave that has struck India over the past few weeks is leading to deaths, electricity shortages and uncertainty about crops and those impacts will likely not remain within its borders.

Impacts include drought, electricity shortages, crop uncertainty — all unlikely to stay within India's borders

A dog walks through an almost dry river bed of Yamuna on a hot summer day in New Delhi, India, on April 30. (Adnan Abidi/Reuters)

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On December 29, 1972, mathematician and meteorologist Edward Lorenz presented a talk at the 139th meeting of the American Association for the Advancement of Science in Washington, D.C. The title being: "Predictability: Does the Flap of a Butterfly's Wings in Brazil Set Off a Tornado in Texas?" 

Though Lorenz was trying to detail the difficulty of weather forecasting, since then, the so-called "butterfly effect" has been used in movies — most notably Jurassic Park — and television to describe chaos theory, or how one small thing may influence something completely unrelated.

While the flap of a butterfly's wings won't necessarily influence the weather thousands of kilometres away, in the face of our rapidly warming planet, there are plenty of reminders concerning our interconnectivity.

Over the past week, stories have splashed across our computer and television screens about the crushing heat wave that has descended across most of India, and for good reason.

India is no stranger to heat waves. Year after year, the country experiences days of intense heat ahead of its monsoon season that brings much-needed rains for crops. 

But this spring has been much different.

Temperatures have soared to near 50 C across almost the entire country of more than 1.3 billion people.

This week on What on Earth with Laura Lynch • Channeling eco-anxiety into a force for change • Feeling the heat in India • How to meet the call to go electric • One listener's solution that's become a campaign.

"This heat wave is quite unusual. March has been the hottest in 122 years, pretty much the hottest year ever since we began recording temperatures," Aditi Mukherji, a principal researcher at the International Water Management Institute out of New Delhi told CBC News in an email. "Heat waves are common in India, but never so early. Then, heat waves are [normally] localized, but this time, it is widespread almost all across [the country]."

While it's not yet clear exactly what factors have played a role in this historic heat wave, scientists believe that it's been affected by climate change.

"This is what we expect from climate change," said Raghu Murtugudde, a visiting research scientist at the University of Maryland's Earth System Science Interdisciplinary Center. "The thing to notice is that if you look at the Middle East, Mediterranean region, that has warmed a lot since about 1990. And that wind that blows from that direction over to India, is now warmer by a lot." 

Loading the dice

That's not to say there isn't some natural variability that's playing a role. Currently, there is a La Niña event occurring. La Niña is part of a natural cycle called the El Niño-Southern Oscillation,or ENSO, where colder waters persist in part of the Pacific Ocean (the opposite, El Niño, means there is warmer water). This can affect weather patterns around the world.

WATCH | El Niño and La Niña explained:

"La Niña sets up a pressure pattern that brings the cold way, way down into peninsular India," Murtugudde said. "We had a colder than normal winter, as we expect from La Niña. Now we are having much warmer than normal spring because that warm air is funnelling straight down all the way into peninsular India."

Then there's the saying: What happens in the Arctic doesn't stay in the Arctic.

"The other thing that's playing into this is that the Arctic has been much warmer than normal. So when that happens, we also get some forces from the Arctic coming south-eastward into Pakistan and India," Murtugudde said. 

"It's a deadly combination of what we call natural variability; things like El Niño and La Niña and anthropogenic warming, global warming. So together they are creating this heat wave, which is unprecedented. But this is what we expect from climate change: It loads the dice."

Impacts across borders

It's not just weather patterns and climate that are interconnected. Heat waves carry with them far-ranging effects, some that have no borders.

The most obvious, of course, is heat-related deaths. While there hasn't been an official count of deaths attributed to this heat wave, the last major heat wave, which occurred in 2015, is believed to have killed 2,500 people in India and another 1,100 in Pakistan. However, that number may be higher, as there has been some concern with the way India reports heat-related deaths

People sleep on the Yamuna river bed under a bridge on a hot day in New Delhi on Sunday. (Adnan Abidi/Reuters)

There's also serious damage to India's already-struggling agriculture sector.

"Wheat crops in major wheat growing belts have been severely affected. The pre-monsoon showers provide the much needed moisture to crops. That was missing, and high heat on top of that made the wheat crop particularly susceptible,"  said Mukherji.

There have also been significant electricity issues, with rolling blackouts. Aside from people being unable to cool themselves off, the shortages affect farmers who need that electricity to irrigate their crops with electric tube wells and pumps, said Mukherji. 

"Food scarcity implications are not clear, as India usually has large buffer stocks of food. If monsoons are also disrupted, and then rice crops are affected (either by droughts or floods), we can expect food prices to rise." she wrote.

A man uses his mobile phone as he sits amidst the outer units of air conditioners, at the rear of a commercial building in New Delhi on April 30. (Adnan Abidi/Reuters)

"However, so far monsoons are predicted to be normal. There are talks of India restricting wheat exports. India is the world's eighth largest wheat exporter. With the war in Ukraine (fifth largest wheat exporter), prospects of procuring wheat from the international market looks bleak."

And with two major exporters of wheat suffering, it's likely to be felt right around the world.

More to come

The worst part is that heat waves have already been occurring more frequently than pre-industrial times and are expected to rise.

In the most recent Intergovernmental Panel on Climate Change (IPCC) report, Climate Change 2022: Impacts, Adaptation and Vulnerability, the panel found that "more intense heat waves of longer durations and occurring at a higher frequency are projected with medium confidence over India and Pakistan."

At a city level, the impacts get more significant.

With 1.5 C warming above pre-industrial levels, Kolkata, India, will on average experience heat equivalent to the 2015 record heat waves every year, while Karachi, Pakistan, would see it about once every 3.6 years, the panel wrote. 

With 2 C warming, "both regions could expect such heat annually."

The hotter it is in India, the more electricity people use to keep cool. That, in turn, increases electricity demand in a country that relies mostly on coal, one of the worst contributors to climate change. And that in turn exacerbates climate change, not just in India, but around the world. It's a vicious circle that is unsustainable, and especially for the poor.

"When India worries about renewable energy mitigation and so on, it has to also worry about adaptation for the poor people to deal with this daily grind, because they have to just think about the next meal,"  Murtugudde said.

"Not the next century or 10 years later. Climate change is here. The future is here."

Flap, flap, flap go the butterfly's wings.


Nicole Mortillaro

Senior reporter, science

Based in Toronto, Nicole covers all things science for CBC News. As an amateur astronomer, Nicole can be found looking up at the night sky appreciating the marvels of our universe. She is the editor of the Journal of the Royal Astronomical Society of Canada and the author of several books. In 2021, she won the Kavli Science Journalism Award from the American Association for the Advancement of Science for a Quirks and Quarks audio special on the history and future of Black people in science. You can send her story ideas at