Revision as of 08:13, 14 December 2020

Heatwave: One word or two?

Oxford Dictionaries spell heatwave as one word, and provide this illustration:

‘when a heatwave occurs many people become increasingly bad-tempered’

In Australia, too, it is one word.

Among major dictionaries Cambridge English Dictionary, Collins English Dictionary and Macmillan Dictionary, too, spell heatwave as one word. Only Merriam-Webster spells it as two.

In large areas, a heat wave is declared when the maximum temperature is 45 degrees Celsius for two consecutive days and a severe heat wave is when the mercury touches the 47 degrees-mark for two days on the trot.

In small areas like Delhi, heat wave is declared if the temperature soars to 45 degrees Celsius even for a day, according to the India Meteorological Department (IMD).

Rise in heatwaves

2001-16

The Times of India, May 21 2016

Jayashree Nandi

Rajasthan's Phalodi recorded the country's highest temperature ever of 51°C. The India Meteorological Department has said the frequency of severe heatwaves had increased sharply in the past 15 years.

Most heat-affected states have no plan in place to prevent mortality and morbidity associated with extreme heat. IMD officials said the average frequency of severe heat waves had doubled from 50 days a year across India until 2000, to about 100 in the 2001-2010 decade. The figures are cumulative numbers from all IMD stations. So, if there are 10 severe heat wave days in two cities simultaneously, it's counted as 20.

“The frequency of both heatwaves and severe heatwaves has increased, particularly in the last two decades. The reasons could be related to climate change, urban heat island effect or others,“ said B P Yadav, director, National Weather Forecasting Centre at IMD.

He added that between 2010 and 2016 too, heatwaves showed an upward trend.IMD has started issuing a separate colour-coded heat wave forecasting from this year, which alerts agencies on when interventions are required, because of what it called a “visible increase“ in both mean temperature and heat wave incidents.

IMD's observations correlate with warnings by the Intergovernmental Panel on Climate Change (IPCC) of a steady increase in warm days and nights globally, and higher temperatures in cities due to the urban heat island effect.

The Indian Institute of Public Health (IIPH), which has developed a heat action plan for Ahmedabad and helped cities in Maharashtra develop theirs, has advised the Union health ministry to ensure that similar plans are implemented in all states affected by heatwaves.

As of now Maharashtra, Gujarat, Telangana and Andhra Pradesh have started a heat action plan.

“Mortality increases as soon as there is a heatwave.For instance, on Thursday when it recorded 48 degrees in Ahmedabad, there were 130 deaths compared to 100 deaths daily on an average.During the 2010 heat wave, there were 310 deaths in a day and about 800 deaths in total in the following week,“ said Dr Dileep Mavalankar, director, IIPH, Gandhinagar.

“Since the frequency of heatwaves is increasing due to climate change, we have been pursuing the implementation of heat plans with the government. Ideally local government administration or municipalities should be in charge of it,“ Mavalankar said.

2017

India Today , The heat is on “India Today” 11/9/2017

The heat is on

A study published this month in Science Advances, an American journal, shows that by the end of the century large parts of India may become uninhabitable due to a combination of heat and humidity. The study examined data based on rising wet-bulb temperatures (TW), a measure of the air temperature combined with humidity, to account for relatively cool days that feel hotter because of high humidity. Once a certain wet-bulb temperature is exceeded, the body can no longer cool itself. According to the study, at these temperatures, "exposure, for even a few hours will result in death even for the fittest of humans under shaded, well-ventilated conditions".

Deaths caused

2010-18

Heat waves killed over 6k since 2010, January 3, 2018: The Times of India

Over 6,100 people have died in India due to heat wave in the last nine years (2010-18) with the year 2015 alone recording nearly one-third such deaths. Among states, Andhra Pradesh had recorded the maximum casualties during 2013-15 period.

Analysis of the casualty figures shows that Andhra Pradesh, Telangana (after its formation in June, 2014), Odisha and West Bengal had together reported over 90% of total deaths due to heat wave during the period.

Sharing the nationwide cumulative figures in Lok Sabha, minister of earth sciences Harsh Vardhan on Wednesday said a latest study had showed that heat waves have increased in many parts of the country with these conditions being experienced generally during the period between March and July.

He, however, said the India Meteorological Department in collaboration with state health departments have started a heat action plan in many parts of the country as “an adaptive measure” to forewarn about heat waves and advise on preventive action to be taken. Figures show that 2,081 people had died due to heat wave in 2015.

2013-16

Deaths caused due to heatwaves, 2013-March 2016; Graphic courtesy: The Times of India, April 27, 2016

The Times of India, April 27, 2016

87 deaths take heatwave toll since 2013 to 4,204 

As many as 87 people died between January and March 2016 owing to a heatwave, with the first three months of 2016 experiencing significantly abovenormal temperatures.

At 56, Telangana recorded the maximum casualties, followed by Odisha (19).Maharashtra, Tamil Nadu, Karnataka and Kerala witnessed one heatwave casualty each.

The deaths in 2013 take India's heatwave toll since 2013 to a staggering 4,204. In 2013, 2014 and 2015, heatwave killed 1,433, 549, and 2,135 peo ple, respectively. The figures were shared by earth sciences minister Y S Chowdary in the Lok Sabha on Wednesday in a written response to a question asked by over nine parliamentarians.

The number may go much higher if states do not take adequate precautionary me asures, as advised by IMD, in view of a forecast of higherthan-average temperatures for this year's summer (April-June). “Above normal heatwave conditions are very likely over central and north-west India during the 2016 hot weather season,“ Chowdary said.

2018

Sushmi Dey, ’31k heat-related deaths of 65+ in India in 2018’, December 3, 2020: The Times of India

India reported over 31,000 heat-related deaths of people older than 65 years in 2018, the second highest in the world after China (62,000), a new Lancet Countdown report on health and climate change shows, reports Sushmi Dey. While heat-related mortality among people above 65 has increased by 53.7% globally during the past 20 years, it more than doubled in India. Globally, 2,96,000 deaths among the age group were reported in 2018.

The report shows India accounted for highest productivity loss at 40% of the total 302 billion work hours lost during 2019.

India’s agriculture sector among worst-affected by heat: Report

The report underlines that livelihoods are at risk because heat is increasingly affecting people’s ability to work outdoors in developing regions with significant economic implications. “India and Indonesia were among the worst affected countries, seeing losses of potential labour capacity equivalent to 4-6% of their annual gross domestic product,” it says. The report highlights that India’s agriculture sector was among the worst affected.

“The pandemic has shown us that when health is threatened on a global scale, our economies and ways of life can come to a standstill,” Dr Ian Hamilton, executive director of Lancet Countdown, said. “The threats to human health are multiplying and intensifying due to climate change and unless we change course, our healthcare systems are at risk of being overwhelmed in the future.”

In 2019, India saw a record number of above-baseline days of heatwave exposure affecting people aged over 65. Eight of the 10 highest ranking years of heatwave exposure in India have occurred since 2010. “The changing climate has downstream effects, impacting broader environmental systems, which in turn harm human health,” says the report.

Impact on health

2012-16: 40m additional Indians affected

‘Heatwaves hit 40m more Indians in 5 yrs’, November 29, 2018: The Times of India

Climate change is hitting home. India saw an increase of 40 million in the number of people exposed to heatwaves from 2012 to 2016 (counting both years), a global report prepared by 27 leading academic institutions, the United Nations and inter-governmental agencies has said.

The surge in heatwaves in India posed a major danger to health and called for urgent action to develop and implement local heat action plans, according to the study.

The Lancet Countdown report on health and climate change, released on Wednesday, said average temperatures in India are projected to rise alarmingly. Between 1901 and 2007, India’s mean temperature rose by more than 0.5 degree Celsius. “While the world is bracing for an increase of around 2 degrees C over the 21st century, northern, central and western India may witness increases averaging 2.2 to 5.5 degrees by the end of the 21st century,” it said.

Heatwaves tied to exacerbation of heart failure, kidney injury

Globally, the Lancet report said, vulnerability to extremes of heat has steadily risen since 1990 in every region, with 157 million more people exposed to heatwaves in 2017 as compared to 2000.

The average person experienced an additional 1.4 days of heatwaves per year over the same period, it said. Low- and middleincome countries, India included, are likely to be worst affected by climate change, given weaker health systems and poorer infrastructure, experts said.

Heatwaves are associated with increased rates of heat stress and heat stroke, exacerbation of heart failure and acute kidney injury from dehydration. Children, the elderly and those with pre-existing morbidities are particularly vulnerable.

Dr K Srinath Reddy, an author of the India policy brief of the Lancet report, said identifying local heat hot spots through appropriate tracking and modelling of meteorological data is needed tackle the crisis.

“Ahmedabad Municipal Corporation has adopted a heat action plan, which necessitates measures such as building heat shelters, ensuring availability of water and removing neonatal ICU from the top floor of hospitals. It has helped bring down the impact of heatwave of vulnerable population. Similar action plan should be developed by other states also,” said Dr Reddy, who is also head of the Public Health Foundation of India.

The Lancet report shows 153 billion hours of labour were lost globally in 2017 due to heat, an increase of 62 billion hours relative to year 2000. The impacts, the authors on India policy brief note, vary with different sectors with the agriculture being most vulnerable as compared to the industrial and services sector.

“For India, whose large agriculture economy makes up 18% of the country’s GDP and employs nearly half the population, this translates into substantial climate-related impacts on the workforce and economy,” said Dr Reddy.

Overall, India lost nearly 75,000 million hours of labour in 2017, relative to about 43,000 million hours in 2000, an increase of over 30,000 million hours over two decades. “For a developing economy like India, this represents a substantial impact on individual, household and national budgets, necessitating urgent national and regional adaptation plans,” the report said.

Impact of heat on productivity/ 1995

The impact of heat on productivity in Afghanistan, Bhutan, Bangladesh, India, Pakistan, Sri Lanka/ 1995
From: July 5, 2019: The Times of India

See graphic, ' The impact of heat on productivity in Afghanistan, Bhutan, Bangladesh, India, Pakistan, Sri Lanka/ 1995 '