23 Prevention and Management of Heat Waves

Dr. Rajnish Ranjan

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Objectives

  • To understand the phenomenon of heat wave
  • To understand the impact of heat wave on human health
  • To understand the vulnerability of India to heat wave
  • To acquaint with the preventive measures of heat waves

   Rationale

 

India has three major seasons- Summer (February to May), Monsoon (June to September) and Winter (October to January).In late summer months, significant rise in the mercury level is observed and the phenomenon of heat wave is experienced in manyparts of the country. Heat wave poses serious risk to health and causes adverse impact to the environment that must be tackled. This module provides an understanding of heat wave management in the country.

 

Heat Wave

 

Unlike other massively destructive hazards such as floods or tropical cyclone, the heat wave is considered slow onset hazard or creeping hazard that sometimes gains more catastrophic than afore-mentioned hazards. Generally, people play down the risk of heat wave as discomfort, rather than as a hazard that could be detrimental to health. Heat Wave gained focus as a major hazard due to heat wave event in Europe last decade. In 2003, Western Europe observed high level of mercury, at some places above 38° C, which deviated about 8-10° C above normal. This resulted in more than 35,000 deaths across the Europe. France was amongst the worst affected with 14,800 casualtie (Hyndman & Hyndman, 2011).

 

When we compare European countries lying in the temperate zone with India which has a dominant tropical climate, we observe thattemperatures such as 38° C may be considered normal by Indian people in contrast to Europeans, as Indians are acclimatized to high temperature. Whereas in

 

Europe where average temperature is low and stable for most part of the year, a moderate deviation from normal results in public emergency. Although this does not mean that deviation from normal temperature does not pose risk in India, it poses immense risk to people. It comes down to risk perception of the people in that they do not see increased temperature as concern to health but merely a natural phenomenon.

 

In India,the typical phenomena of heat wave was observed in 1998 (U.S.De & Rao, 2005) and latest in 2015. In the year 2015, heat wave caused death of at least 2,500 people in multiple regions. South

 

Indian states of Andhra Pradesh and Telangana were the most affected due to heat waves. The number of casualties were 1735 and 585 respectively for both states. Other casualties were also reported from the state of West Bengal and Odisha. Heat Wave leading to extensive casualties calls for effective prevention and management for the hazard.

 

Criterion for heat wave in India

 

Heat Wave is marked by the period of abnormally high-temperatures, more than the normal maximum temperature that occurs during the pre-monsoon (March to June) summer season. Indian Meteorological Department (IMD) came up with following criteria to define heat wave.

 

Heat wave need not be considered till maximum temperature of a station reaches at least 40°C for Plains and at least 30°C for hilly regions.

 

a) When normal maximum temperature of a station is less than or equal to 40°C

 

Heat wave departure from normal is 5°C to 6°C

 

Severe Heat wave departure from normal is 7°C or more

 

 

b) When normal maximum temperature of a station is more than 40°C

 

Heat wave departure from normal is 4°C to 5°C

 

Severe Heat wave departure from normal is 6°C or more

 

 

c) When actual maximum temperature remains 45°C or more irrespective of normal maximum temperature, heat wave should be declared.

 

World Meteorological Organization(WMO) defines a heat wave as the phenomena of five or more consecutive days during which the daily maximum temperature exceeds the average maximum temperature by five degrees Celsius.

 

Impact of heat wave on human health

 

Human body tries to regulate core temperature within healthy limits which is about 37°C through a process termed homoeostasis. With mild exercise, the temperature of body increases to about 38-39°C without any harm to health until the thermoregulatory system is within its control range. Staying within the control range requires the body to balance heat production by the body and possible other heat gains (For e.g. solar radiation) with the resultant heat loss. The heat loss is primarily by regulating body temperature through sweat production and regulating blood flow. During Heat waves, proper functioning of both systems is essential for thermal regulation. If they are immensely stressed and cannot match the thermoregulatory demands this leads to excessive strain on the body and eventually may cause heat illness. Heat syncope, heat exhaustion and heat strokes are some of the heat related illnesses.Heat Syncope is related to heat exposure that produces orthostatic hypotension. This hypotension can precipitate a near-syncopal episode. Heat syncope is believed to have resulted from intense sweating, which leads to dehydration, followed by peripheral vasodilation and reduced venous blood return in the face of decreased vasomotor control.Heat exhaustion is marked by excessive dehydration and electrolyte depletion. Symptoms may include diarrhoea, headache, nausea and vomiting, dizziness, tachycardia, malaise, and myalgia.

 

Heat cramps are painful, often severe, involuntary spasms of the large muscle groups used in strenuous exercise. Heat cramps tend to occur after intense exertion. They usually develop in people performing heavy exercise while sweating profusely and replenishing fluid loss with non-electrolyte containing water. When body temperature increases up to 40°C or more it results in Heat stroke. It is characterised by delirium, seizures and coma. This is the potential fatal condition. The above mentioned conditions are direct effect of heat wave on human body but there are likely different mechanisms through which a person may die during a heat wave due to environmental temperature combined with extra strain on cardiovascular system. It is characterised by dehydration, display of increased blood viscosity and other physiological changes. In theory, any illness that compromises thermoregulation will increase the risk of heat related death(Kovats & Hajat, 2008). If exposure of heat wave is severe enough, even healthy person may fall for heat stroke.

 

Figure 1 Symptoms of Heat related Illness

 

 

Source: (Mohney, 2016)

 

Vulnerability of heat wave in Indian Context

 

Vulnerability to Heat Wave is highly dependent on the health status of the individual. Besides that other determining factors of heat wave hazard vulnerability are the socio-economic and environmental characteristics that includes the age, gender, income, marginalization & social isolation (thereby reduction in access to remedial measures and information), vegetation, and health characteristics (Azhar, Saha, Ganguly, Mavalankar, & Madrigano, 2017).

 

Vulnerability Map of Heat Wave shows that 10districts in India are having very high vulnerability for heat wave. Most of these districts are in central India- Madhya Pradesh and Chattisgarh. The most vulnerable districts are Dakshin Bastar, Dantewada, Bijapur (Chhattisgarh), Pakur (Jharkhand), Alirajpur, Sheopur, Barwani, Jhabua (Madhya Pradesh), Malkangiri (Odisha), Banswara (Rajasthan) and Dohad (Gujarat). The low vulnerable districts are along the western side of the western ghats. 97 Districts in India fall under the high vulnerability to Heat Wave, and 213 districts fall in Higher than normal vulnerability to Heat Wave.

 

Figure 2 Heat Wave Vulnerability Index Map

 

Thus, a high vulnerability to heat wave hazardnecessitates us to take appropriate measure in terms of its measurement and prevention.

 

Management of Heat wave

 

a) Preparation of Action Plan: Preparing an action plan is an ideal way to tackle the heat wave. Given the administrative set-up of the country and socioeconomic variability this action plan should be developed at the level of local self-government i.e. Municipal Corporations or Zilla Parishads.Ahmedabad Municipal Corporation in the state of Gujarat was first to come up with such Action Plan in 2013 and it has beenupdating the plan on a regular basis . The major focus of the action plan is on developing an Early Warning System,characterizing well structured organizational responsibilities, developing health care services to cater to heat-related illnesses and promoting adaptive measures. Other than Ahmedabad, 17 cities developed their own specific action plans containing public education, warning for high temperature and suggestions to tackle excessive heat. These cities included Nagpur, Gondia, Chandrapur, Akola and Jalgaon in Maharashtra and Bhubaneswar, Puri, Koraput and Baleshwar in Odisha (Sinha, 2017).

 

b) Developing Early Warning System: An end-to-end Early Warning System is very helpful to minimise the risk of heat-wave related illnesses. This can be done by issuing advisory to people through local news channel, newspaper, radio etc. Ahmedabad Heat Action Plan devised colour signals for Heat Alert which is as follows.

 

Figure 3 Color Signal for Heat Alert

 

 

 

(Source: Ahmedabad Heat Action Plan)

     From last year, Indian Meteorological Department began issuing heat wave bulletins. These were transferred into local alerts by municipal authorities to issue early warning to citizens.

 

c) Public Awareness and Community outreach: To increase the preparedness of communities , constant public awareness campaign is necessary. This can be implemented through spreading messages such as how to protect against heat-wave by means of print, electronic and social media.

 

Running commercials on Electronic media, radio regarding Do’s and Don’ts for heat wave. Odisha initiated awareness campaign for heat wave in vulnerable districts from 2002 to 2008 under the Disaster Risk Management Program. The awareness campaign was implemented in collaboration with United Nations Development Program (UNDP) , wherein volunteers from the communities were trained to disseminate information regarding “Do’s and Don’ts” at the grassroot level. Through media broadcasts heat wave advertising campaigns were held. The major focus of Disaster Risk Management was on what to do in order to avoid heat stroke, symptoms of heat attack and first aid information. The media used for this campaign were both electronic and print media including posters and pamphlets. These campaign helped in reducing the mortality due to heat wave over the years. Transfer of information and reach of the awareness programdepended on theliteracy levels, diffusion of technology such as television and radio in the concerned areas. To reduce the exposure of heat waves the working hours, timings of school and bus were changed. Adequate supply of water and electricity was also ensured (Das & Smith, 2012)

 

d) Participation of NGO’s and Civil society: With the participation of non-governmental organizations and civil society to improve access to water, development and strengthening of temporary shelters and bus stands and developing means to tackle heat wave condition.

 

Prevention of Heat wave

 

To prevent heat wave there is a need to consider this phenomena as the risk to health rather than considering it merely a natural phenomenon. Some simple step of Do’s and Don’ts should be followed at the individual level to tackle heat wave.

 

Avoid going out in the sun, especially between 12.00 noon and 3.00 p.m. Drink sufficient water and as often as possible, even if not thirsty

 

Wear lightweight, light-coloured, loose, and porous cotton clothes. Use protective goggles, umbrella/hat, shoes or slippers while going out in sun.

 

Avoid strenuous activities when the outside temperature is high. Avoid working outside between 12 noon and 3 p.m.

While travelling, carry water with you.

 

Avoid alcohol, tea, coffee and carbonated soft drinks, which dehydrates the body. Avoid high-protein food and do not eat stale food.

 

If you work outside, use a hat or an umbrella and also use a damp cloth on your head, neck, face and limbs

 

Do not leave children or pets in parked vehicles

    If you feel faint or ill, see a doctor immediately.

 

Use ORS, homemade drinks like lassi, torani (rice water), lemon water, buttermilk, etc. which helps to re-hydrate the body.

 

Keep animals in shade and give them plenty of water to drink.

 

Keep your home cool, use curtains, shutters or sunshade and open windows at night. Use fans, damp clothing and take bath in cold water frequently.

 

Figure 4 A typical heat wave awareness poster

(Source: Ahmedabad Heat Action Plan)

 

Urban Heat Island Effect

 

Urban Heat Island(UHI) refers to surface and atmospheric modifications due to urbanization generally leading to modified thermal climate that is warmer than the surrounding non-urbanized areas (Borbora & Das, 2014). Higher urban heat is a result of heat released from anthropogenic activitiesincluding exhaust from vehicles, power plants, air conditioners and other heat sources and also in the form of solar radiation. All anthropogenic heat enters into environment directly. Part of solar radiation heat the environment directly, the rest is absorbed by the complex urban built structure and hit the environment indirectly. The increased temperature in urban localities lead to the Urban Heat Island Effect that may affect the number of hot days. It is also known to increase the duration of heat waves, thereby increasing the potential risk of mortality from heat stress(Tan, et al., 2010).” There exists correlation between UHI and Heat wave observed through various academic research. It has also been observed that mortality is more sensitive to heat in urban areas compared with rural and suburban areas. The adverse effect on human health due to increased exposure of extreme thermal conditions due to the UHI enhances the intensity of heat waves (Tan, et al., 2010). Urban Heat Island(UHI) contributes exacerbating the effects of heat wave. However, the degree of UHI varies from place to place due to the level of urbanisation, land-use land- cover, vegetation cover etc.The incorporation of proper town planning measures including greenery and water resource managementreduces the catastrophic effects of urban heat island phenomenon(Brucker, 2005).

 

Case Study of European Heat Wave of 2003

 

Heat Wave in 2003 in some of the European countries was unprecedented and massive. But, Heat Wave had also been observed in Europe before 2003. There was an episode of heat wave in France in 1983 which killed more than 300 people, Athens(Greece) observed severe heat wave in 1987 resulted in death of 2000 people. Other countries such as UK (1976,1995), Portugal (1981), Netherlands (1994) have also experienced heat wave before 2003 (Kovats & Hajat, 2008). Yet, Heat Wave of 2003 was different. This heat wave was result of high temperature anomaly and associated drought and dry weather(Garcia-Herrrera, Diaz, R.M.Trigo, Luterbacher, & Fischer, 2010). The temperature anomaly was amplified by severe soil moisture deficit originated in the previous months, as a consequence of the below average precipitation in earlier winter and spring (Garcia-Herrrera, Diaz, R.M.Trigo, Luterbacher, & Fischer, 2010). The result of Heat wave was cascading and far reaching. It resulted in higher mortality, forest fires, restricted electricity and big economic losses. The mentioned figure 5 describes number of death associated with European Heat Wave in different countries with threshold of normal temperature and deviation from the threshold.

 

Figure 5 Number of deaths associated with European Heat Wave

 

Source: (Garcia-Herrrera, Diaz, R.M.Trigo, Luterbacher, & Fischer, 2010)

 

The impact of 2003 Heat Wave was particularly devastating for France. In the August 2003, mortality increased by 60%, compared to average values observed for the same interval of 1999-2002 period. The increase was mostly observed in most of the vulnerable population i.e. elderly and women. 70% increase in mortality was of elderly as compared to reference period (1946-2002). Women mortality showed about 80 percent increase among women (9510) compared to men (5292). The pattern can be observed in the other countries, although number of death varied due their pre-existing vulnerabilities. Other than age and gender, social class status of the victims was another important factor. Lower social class groups were considered more vulnerable. The social class status was also corroborated to less-air conditioning and having few rooms (Garcia-Herrrera, Diaz, R.M.Trigo, Luterbacher, & Fischer, 2010).

 

The heat wave contributed to large amount of total burned area (739,000 ha) in the five European countries namely Greece, Italy, France, Portugal and Spain. In Portugal, forest fire concentrated in the central region of the country and resulted in massive total burned area. The area burnt between 1stand 7th August was roughly 200,000 ha and estimates for total burnt area for the end season was 431,000. This represents roughly 5% of the Portuguese territory. Impact on the agriculture was profound too. Italy, Germany, Austria, Spain, France and Portugal had a poor agriculture season. This was due to the combined effect of the drought and the excessive temperature since June 2003. This resulted in the increased production cost and increased risk for harvest, productivity and markets. Fodder sector and Livestock (poultry and egg) production was affected.Fodder deficit varied from 30% (for Germany, Austria and Spain) to 40% (Italy) and 60% (France). Almost 4 million broilers died in France due to Heat wave, and the Poultry flock was reduced by about 15% to 20% in Spain(Garcia-

 

Herrrera, Diaz, R.M.Trigo, Luterbacher, & Fischer, 2010). Potato production in the European Union was decreased by around 5%, with Germany (−25%) and Spain (− 30%) had the highest reduction. The Heat Wave also had an impact of heat wave on the power sector, mainly on the prices and hydroelectricity plants(Fink, Brucher, Kruger, Leckebusch, Pinto, & Ulbrich, 2004). Electricity prices increased above 100 Euros/MWh. The flow of the central European rivers reached all-time low levels in August and September (2003). Due to the reduced flow, Hydroelectricity plants were forced to reduce their production of electricity because they were unable to divert enough cooling water from the rivers. German nuclear facility Isar1 reduced its power generation by about 40 percent (Fink, Brucher, Kruger, Leckebusch, Pinto, & Ulbrich, 2004).Many French nuclear power plants suffered from overheating which led to interruptions of power(Garcia-Herrrera, Diaz, R.M.Trigo, Luterbacher, & Fischer, 2010).

 

Case study of European Heat Wave of 2003 shows that the Heat Wave has the potential to becatastrophic. Heat wave impacts not only in terms of mortality but had detrimental effect on key drivers of economy such as agriculture, electricity generation. There is a need of improving the quality of facilities and disaster management capacity of respondents- both officials and volunteers(Brucker, 2005). Identification and capacity building of vulnerable people is also necessary step to address heat wave risk. At the time of Heat wave of 2003, only two cities in Europe, Rome and Lisbon provided heat wave alert system. In 2010 (Garcia-Herrrera, Diaz, R.M.Trigo, Luterbacher, &  Fischer, 2010) many European cities developed extreme temperature prevention plans and alert plans, which was get activated once weather forecasts indicates safety threshold set for the specific locality or town being exceeded. Europe analyzed the negative consequences of 2003 Heat wave, learnt from past failures, invested on capacity building measures to develop greater resilience to heat waves.

 

A robust weather monitoring, heat wave advisory network, information dissemination network along with the building up of heat wave management capacities in the respondents would bring about increased adaptive capacity to face the risk of heat waves in India.

 

Heat Waves Response in India

 

Heat Wave has an effect on almost all the level of people in the affected areas. But the severity of impact and the response required for the severity varies. A large number of people would be facing minor discomforts and mild symptoms which could be effectively catered to by ensuring appropriate awareness about heat wave phenomenon and thereby self care would suffice. A significantly lesser number of people would be more severely impacted and effects such as cramps, heat exhaustion or heat syncope would require medical aid from physician (either personally or through telephonic media) or a visit to a clinic and mild medication. A far lesser number of people would suffer from heat stroke thereby requiring the services of ambulances and admit to emergency rooms and intensive care from expert doctors. Ever less number of people would succumb to severe effects of heat stroke.

 

Figure 6 Severity of effects, proportion of affected population and necessary response mechanism for Heat Wave

Phenomenon

 

The heat wave of 2015 in the states of Andhra Pradesh, Telangana and Karnataka led to offices, schools and colleges shutting down during peak heat hours. Schools were instructed to advice children to return to their home before 1.O’ clock in the afternoon. MGNREGA work was halted during the peak heat hours. In Ahmedabad, construction projects were asked to give their workers a two-hour break. Public Parks were kept open the entire day to enable people to rest. Free and adequate drinking water at public places was ensured by governments. Oral Rehydration Solutions(ORS) were distributed freely. Social media platforms were used to spread awareness and to communicate advisories. Thus we observe that proper measures in awareness generation and self-care would lead to a significant reduction in the requirement for specific and expert response.

 

Probing Heat Wave management

 

Heat wave emerged as a major hazard in last few years. The impact of heat wave on humans, economy, livestock and environment has necessitated the seriousness of preparedness, mitigation and response to heat waves similar to fast onset damaging events like cyclones or other major hazard. Heat wave affects day-to-day life of people. The European Heat wave of 2003 showed the necessityfor preparedness to heatwave to build disaster management capabilities with respect to public health, Monitoring and Forecasting of heat wave and a sound early warning system.

 

The objective of the alert system must be to set up strengthened action and prevention measures, based on sound advice for vulnerable populations. Risk perception to advisories on heat waves could not be considered serious due to above 38°C being moderately frequent in most states across our nation. Advisories are generally also disregarded due to the socio-economic conditions that necessitates every day labor in order to receive wages in a hand-to-mouth existence. The consideration of vulnerability parameters and the corresponding measures to reduce vulnerabilities and building capacity for response and risk reduction are extremely important. Changing demographic trend and an ageing population add to the risk of Heat Wave. People working in quarries, farms, daily wage labourers are more vulnerable and at more risk of heat wave in India. Simple preventive steps needed to be taken to mitigate the impact of heat wave.

 

Heat wave cannot be controlled in terms of severity or appearance or duration, but it is manageable and preventable following some simple solutions as described above. A targeted awareness campaign with inclusion of temperature alerts and instructions to avoid heat can significantly bring down death toll. Notion of heat wave merely as natural event whose effect are inevitable need to change. As European heat wave of 2003 displayed range of vulnerabilities in the European society and deficiency in response system. Preparedness, Continuous monitoring and timely early warning will definitely help in reducing the detrimental effects of the heat wave on not only human society but also on the whole ecosystem.

 

The changing demographics, increased urbanization, changing socio-economic conditions and the increased frequency of high magnitude-high intensity hazard events require the need to focus on planning housing and social integration.

 

Summary

 

World Meteorological Organization (WMO) defines a heat wave as five or more consecutive days during which the daily maximum temperature exceeds the average maximum temperature by five degrees Celsius. Heat Wave are marked by the period of abnormally high-temperatures, more than normal maximum temperature that occurs during the pre-monsoon (March to June) summer season. Heat syncope, heat exhaustion and heat stroke are heat related illnesses characterised by dehydration, display of increased blood viscosity and other physiological changes. Urban Heat Island(UHI) contributes to exacerbating the effects of heat wave. Heat Wave has an effect on almost all people in the affected areas. But the severity of impact and the response required for the severity varies. Proper measures in awareness generation and self care would lead to a significant reduction in the requirement for specific and expert response.A targeted awareness campaign with inclusion of temperature alerts and instructions to avoid heat can significantly bring down death toll. Notion of heat wave merely as natural event whose effect are inevitable need to change.

 

you can view video on Prevention and Management of Heat Waves

 

References

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