- June 12, 2019
Heatwaves and health impacts – How climate change could devastate India
Churu, an obscure little town on the eastern edge of the Thar desert in Rajasthan, has in recent years shot to prominence as India’s hottest place. This year, once again, Churu broke its own record and registered a sweltering 50.8 degrees Celsius at the end of May. And it isn’t just Churu feeling the heat, about two-thirds of the country has been in the grips of a severe heatwave with places across northern, central and parts of southern India routinely experiencing maximum temperatures of over 45 degrees Celsius in the past three weeks. According to the world weather monitoring website El Dorado, eleven of the fifteen hottest cities in the beginning of June were in India.
The IMD, in its seasonal temperature outlook for the summer of 2019, had noted that most regions in the country are likely to face temperatures between 0.5 degrees and 1 degree Celsius warmer than normal. As the country eagerly awaits the full onset of the monsoon over mainland India, there can be little doubt that IMD’s summer temperature forecast, started only in 2016 in recognition of increasing intensities of summers, has been accurate.
What remains worrying is that the severe summer this year, falls perfectly in line with projections that show intensifying Indian summers and increasing heat-related mortality over the next several decades, as the world continues to warm. Research by IMD scientists have revealed steep increases, especially in the south and west of the country, in the number of days that record daily maximum temperatures above 37 degrees Celsius. Answering a question in the Lok Sabha on 6 February, Harsh Vardhan, the minister for the Ministry of Earth Sciences, revealed “significant increasing trends” over most of mainland India with regards to heat wave days.
A 2014 research paper from IIT-Bombay that relies on multiple simulated models based on observations between 1969 and 2009 has projected both an increase in the spread and intensity of heat waves as well as related mortality across models. Another study from 2015 published by the Indian Institute of Management Ahmedabad, predicted a likely increase in the number and intensity of heat waves almost throughout the country except pockets in the east and north east. According to the study, an increase of about 3 degrees Celsius in temperatures would increase the death rate by about 70 per cent and a worst-case 6 degree increase (at the current rates of emission) by the end of the century would see an increase in mortality of about 140 per cent.
More recently, in 2017, research on heatwave mortality trends in India showed that a 0.5 degree Celsius rise in average summer temperatures could increase heat-related deaths two-and-a-half fold over the next 50 years, especially in heat wave prone regions. The situation is likely to be particularly dire in cities where a combination of concrete, glass and high levels of air pollution are known to trap heat. This ‘heat island effect’ has been estimated to increase ambient temperatures by as much as 4.4 degrees Celsius as compared to a similarly located natural environment.
The health impact of excessive heat, however, is due to more than just high temperatures. Local factors, especially humidity, have a significant role in determining how the human body perceives and reacts to higher temperatures. Depending on these factors, prolonged periods of heat are known to exaggerate pre-existing health conditions and put tremendous stress on internal organs. This is the reason around 70,000 and 55,000 deaths in Europe and Russia were attributed to the heat waves in 2003 and 2010 recently. It was later revealed through a thorough analysis of the demographics that a large proportion of those who died were old and suffered from pre-existing illnesses.
Similarly, coastal regions with a higher relative humidity have been observed to have higher rates of heat-induced casualties. While recognition of this variability of sensitivity has existed for some years now, this factor that converts absolute temperature into equivalent temperature felt for the body- the heat index, has so far not been included in the forecasts or advisories issued by the IMD. Unsurprisingly, the cloudiness regarding the links between heat waves and mortality extends to a murkiness regarding statistics of heat-induced mortality.
Although heat is known to exaggerate pre-existing health conditions and put tremendous stress on internal organs, only deaths due heat strokes have been monitored in India. As a result, deaths that happen from exacerbation of renal or respiratory conditions due to over-exposure to heat are not counted among heat-related fatalities. According to a multi-institutional study that looked at the rate of mortality during the May 2010 heat wave in Ahmedabad found that mortality rate from all causes was higher than the average mortality rate in the month of May by 43 per cent.
This discrepancy in the numbers has contributed to common underestimation of the burden of heat related health impacts while also making it difficult to track. Still, according to official statistics maintained by the National Crime Records Bureau, heat strokes are one of India’s biggest natural killers and have accounted for 15,456 deaths between 2000 and 2015. In 2015, the last year for which data pertaining to accidental, natural and unnatural deaths was made public, NCRB attributed 1908 deaths to heat strokes, an almost four-fold increase from the 534 deaths recorded in 2000. Numbers provided by MOES minister Harsh Vardhan in his 6 February reply to the Lok Sabha, indicate that since 2015, there has been a sharp drop in the deaths due to heat waves.
According to the minister, there have been a total of 1095 heat wave deaths from 2016 to 2018, of which only 20 deaths were recorded in 2018. While the minister’s answers reflects increasing preparedness for heat waves, it must also be noted that these numbers differ vastly from the heat stroke deaths recorded by the NCRB up to 2015 and are about a third lower. This year, disparate media reports cumulatively peg fatalities at around 40 across the country although no official numbers have been released.
While there can be some scepticism around the numbers, there has also been a clear movement towards preparedness for heat waves, especially at local levels of government. Following Ahmedabad, the first city to adopt a City Heat Action Plan in 2013, Nagpur and Bhubaneshwar too released their own action plans to tackle heat waves a few years ago. The city action plan, with a help of colour-coded classification and early warning systems, works in spreading awareness of the health risks and preventive measures to be taken during extreme heat as well as in streamlining coordination between different civic agencies concerned with the mitigation.
The plans have enabled local authorities bring down urban heat-related mortality drastically. The success of such plans has prompted state governments to prepare larger plans that could be implemented in rural areas as well. In the last two years, Karnataka, Telangana, Andhra Pradesh, Uttar Pradesh and Haryana, have all developed and implemented Heat Wave Action Plans in coordination with the National Disaster Management Authority.
Still, several states are yet to act on the intensifying threat of heatwaves and coordination between different government agencies and health bodies have remained low. While preparedness overall remains at a nascent stage, governments seem at least to have woken up to these routine realities of climate change.
This post is authored by Shreeshan V, who writes on climate change and is a member of the editorial team at CarbonCopy. The contents of this post are copyrighted to CarbonCopy, and any reproduction must be duly cited.