India and Pakistan have been sweltering under an unprecedented heatwave, the severity of which scientists attribute to climate change. In this episode of The Conversation Weekly podcast, we explore how much worse heatwaves in the region could get and how farmers can prepare.
Since March, people in India and Pakistan have faced near continuous heat well above 40℃. Nearly a hundred people are estimated to have died from the extreme heat, which is also affecting harvests, causing forest fires and power blackouts. Delhi recorded a record high temperature of 49.2℃ in mid May, and the mercury reached 51℃ in Jacobabad, a city in southeastern Pakistan.
What's also made this heatwave so remarkable is when it started and how long it's lasted. Heatwaves in May are common as the region approaches the monsoon season, but this one started in March and has persisted for three months with few breaks. "These heatwaves are hotter than they usually are in this region at this time of year," explains Andrew King, a senior lecturer in climate science at the University of Melbourne in Australia.
"In general in this region, we're seeing temperatures rising, but if we look at the most extreme heatwave temperatures, we haven't seen an increase up until now. It's more that the heat waves have become a bit more frequent," says King. However, he says climate models project heatwaves in the region will become both hotter, and more frequent.
But how do you measure how extreme a heatwave actually is for a particular region? Alan Kennedy Asser, a research associate in climate science at the University of Bristol in the UK and his colleagues have found a way to do just that. They recently published a study analysing the most extreme heatwaves in the world over the past 60 years. Crucially, they did this by calculating how much each heatwave varied from the recent average for that region.
When they looked at the data for India and Pakistan, Kennedy Asser says they found that previous heatwaves in India and Pakistan were not "anywhere near as extreme as some of the other heatwaves around the world". Given what extremes have happened elsewhere, he says "there could be some seriously big heat waves down the line" for places like India and Pakistan.
As the heatwave affected the wheat harvest, India banned export of wheat in mid May. In the state of Punjab in northwestern India, many farmers grow wheat in the winter months that is harvested in April, and then switch to growing rice during the summer monsoon season. Shruti Bhogal, who's just finished working as a research associate for a project run by the University of Cambridge in the UK on agricultural sustainability in Punjab, says the intensity of the heat, so early in the wheat-growing season, led to a reduction in yields for farmers.
Now there are concerns the rice paddies could be affected too. "Of course, there's the heat stress, but there's going to be water stress as well," explains Bhogal, adding that the coming rains are expected to be erratic. Bhogal explains how farmers are being encouraged to diversify the types of crops they grow to reduce their vulnerability to the changing climate.
Listen to the full episode on The Conversation Weekly podcast to find out what's in store for the region.
This episode was produced by Mend Mariwany, with sound design by Eloise Stevens. Our theme music is by Neeta Sarl. You can find us on Twitter @TC_Audio, on Instagram at theconversationdotcom or via email. You can also sign up to The Conversation's free daily email here.
Authors: Daniel Merino - Assistant Science Editor & Co-Host of The Conversation Weekly Podcast, The Conversation | Gemma Ware - Editor and Co-Host, The Conversation Weekly Podcast, The Conversation | Alan Thomas Kennedy-Asser - Research Associate in Climate Science, University of Bristol | Andrew King - Senior Lecturer in Climate Science, The University of Melbourne