India's Rising Heat Crisis: Tragedy Near Mumbai A Turning Point?
Nobody died in climate change-powered Cyclone Biparjoy. Lessons learnt after 1999's devastating super-cyclone helped. It's time for a repeat to save lives from climate change-powered killer heat.
June saw sweltering heat in many parts of India. The sun was blazing, and humidity high - a sign of the eagerly awaited monsoon. Standing outdoors can drench you in sweat and deplete your energy faster than an old mobile phone - probably in a matter of minutes.
Source: Reuters
3rd July, 2023: Hottest day recorded on Earth. Source: Robert Rhode, Lead Scientist @BerkeleyEarth
But this summer has been different, not in the heat as such but the extent of danger made abundantly clear. The deaths of at least 15 people at a political rally in just one afternoon can be seen as the tragic start of a series of new insights into fatal heat. While many more died in June, 2023, some local officials have said these were not due to heat. This is in sharp contrast to what happened on the 16th of April where fewer deaths at just one location in a few hours has probably done more to focus attention on killer heat.
Tens of thousands of people started arriving at the International Corporate Ground in Kharghar, in Navi Mumbai, just east of Mumbai, for a rally organised and overseen by the Chief Minister of Maharashtra. It was a high-profile event attended by the Union Home Minister to honour a prominent social activist with a prestigious state award, the Maharashtra Bhushan. There was some cooling visible on the stage and some umbrellas in the crowd which had swelled to an estimated 700,000 by the afternoon around 2 by when the event was wrapping up. This is when temperatures tend to hit the maximum. There was little other shelter in sight.
Images from the Kharghar rally, near Mumbai, organised by the state government on 16th April, 2023. Fifteen people died, most on the same day. Source: CM’s Office tweet
By about 5-5:30 pm, a nearby hospital started getting patients being rushed to emergency and eleven people had died, the cause attributed to heat stroke and heat stress. There were more deaths to follow.
What Went Wrong
So what exactly happened? And what are the learnings?
In early June, the bureaucrat tasked with conducting an inquiry to avoid such tragedies in the future has asked for one more month to submit his report. India’s heatwave season is typically from March to June and the Khargar tragedy is rare as deaths linked to extreme heat usually take a long time to ascertain.
But initial reports suggested that the victims hadn’t eaten anything for 6-7 hours or drunk much water, there was no shade, most of the victims above 50 years old, and the autopsies on 12 victims confirmed they died of sunstroke, a medical official was quoted. Experts blamed heat stress, the result of staying exposed under the sun for long hours and the need to check for comorbidities in the victims.
The Indian Meteorological Department (IMD) did not issue a heatwave warning for at least two reasons. Firstly, there’s no weather station in Khargar and, secondly, the nearest station is only a few years old so there isn’t enough long-term data to issue a warning.
“If there is more moisture in the air then the cooling mechanism of the human body, which is based on sweating and its evaporation mechanism, slows down”
Heat Index - ‘Feels Like…’
It’s not just the temperature but the humidity which is important as well. Compared to 40° celsius in a dry climate (like Delhi in April), June’s 40°C feels like much more. A heat Index puts a number to this.
Kharghar, close to the sea, was hot and humid. The temperature at the nearby station was 38° and relative humidity 47%. But the Heat Index, the ‘feels like’ temperature was blistering 47°, according to a new calculator (try it here for your area).
It was 38° in Khargar - but ‘felt like’ 47° with high humidity, according to a new heat index calculator by the Barcelona Institute for Global Health
The Heat Index danger mark is 35° - which is what the skin temperature is regulated at normally. “If there is more moisture in the air then the cooling mechanism of the human body, which is based on sweating and its evaporation mechanism, slows down,” is how an IMD official explained it to this columnist.
In fact, barely a fortnight after the tragedy the IMD launched a much-needed Heat Index forecast. It’s based on the maximum temperature and humidity forecast for 2:30 pm. Hopefully this will be quickly adopted by authorities to help protect people and take precautions like is done so smoothly in several states ahead of cyclones. This is still work-in-progress, the met says this is “experimental” and “not validated over India;” it needs to be validated with health data.
Heat Index Forecast, an initiative by the Indian Meteorological Department. However, this is still work in progress. Source: IMD
Killer Heat But Deaths Not Being Recorded Systematically?
The IMD may not have revealed much yet but it appears that beyond 35° the warning can start. But this may still be too high, a recent report points out. The Barcelona Institute for Global Health (ISGlobal) questions whether the danger point should be lowered to 28°C as that’s when the human body can start to experience “serious strain… with 31°C representing the upper limit for adverse heat-related health effects.” It says that 2022’s record breaking heatwave in India and Pakistan, which saw temperatures (and not the Heat Index) as high as 50°, reached the thresholds thought to be at the very limits of human survival to extreme heat.
Experts at the World Weather Attribution (WWA), which rapidly investigates links between an extreme weather event and global warming, say the lack of reliable medical data from the 2022 heatwave in South Asia has limited the lessons we could learn from this disaster. The number of deaths in Europe during the 2022 heatwave is estimated between 15,700 to over 20,000. According to official data in India the number of deaths during the March-May, 2022, record-breaking heatwave was 15. It’s reasonable to expect that the actual deaths in a record breaking, months-long heatwave would have more deaths than Kharghar’s 15 in just one day. This suggests that heatwave deaths are not being recorded systematically.
From 1-in-100 Years to 1-every-2 Years
But the WWA, which includes scientists from India, also says heat waves in the region are going to get worse. Heatwaves like the one in April, 2023, across India and Bangladesh used to occur less than once a century on average, but now they can be expected around once in five years. This could be “at least once every two years” on average if global warming rises from the current 1.2° to 2° above pre-industrial times. And that “will happen within around 30 years if emissions are not cut rapidly.”
Dr Friederike Otto, WWA, describes heat waves as one of the “deadliest” weather events there are. Extreme heat kills more than any other extreme weather events linked to climate change like cyclones. Notably, Cyclone Biparjoy, which had all the fingerprints of climate change and which hit the western state of Gujarat, caused no loss of life; data and disaster management systems to protect lives in such storms have been built up and fine-tuned specially since the 1999 super cyclone that hit Odisha and killed thousands. The same needs to be done urgently for extreme heat waves now.
Indian authorities from the central to city levels do have heat action plans in place, although a recent study found these under-prepared. The National Disaster Management Authority has a lucid cheat sheet (see charts below); vulnerable states like Odisha and Gujarat do take preventive steps. While there may be questions about the efficacy of such plans, there seems to be little doubt that these will be tested far more frequently in the future.