The global temperature hike is leading to frequent heat waves (Tmax > 40C for at least two to five consecutive days) events that have dire consequences on human health and well-being. According to the recently published sixth assessment report (AR6) by the Intergovernmental Panel on Climate Change (IPCC), the global surface temperature from 2001-2021 was estimated to be 0.99C (0.84C-1.10C) higher than the average temperature from 1850-1909. The increase is 1.09C (0.95C to 1.20C) from 2011-2020 in average temperature compared to 1850-1900. The report also predicts the rise of temperature and intensification of extreme events in the near future.
Rising temperature results in heat waves and an extended period of higher day and night temperature generate cumulative physiological stress on the human body that aggravates the top causes of global deaths (WHO, 2018).Exposure to higher temperatures also causes public health emergencies, and cascading socioeconomic impacts such as loss of work capacity and labour productivity, and mobility, and exacerbates poverty (Stapleton, 2014; WHO, 2018).
Over the last few decades’ anthropogenic activities have triggered the pace of temperature rise by emitting a tremendous amount of greenhouse gases (GHGs) into the atmosphere. A report by Carbon Brief includes that since the pre-industrial era more than 2,500bn tonnes of CO2 (Gt CO2) have been released into the atmosphere by human interventions (Carbon Brief, 2021). The excessive amount of GHG in the atmosphere catalyzes the greenhouse effect, and thus the globally extreme temperature events are observed to increase by frequency, magnitude, and duration.
Continuous exposure to excessive heat causes serious health conditions such as heat rash, excessive sweating, heat cramps, exhaustion, heatstroke, and even death. Multiple studies (Haines, 2021; Bates, 2020; Karmanev, 2014)estimate that from 2000 to 2016 the number of people exposed to heat waves increased to 125 million worldwide, and only in 2015, 175 million additional people were exposed to heatwaves. In 2003, more than 70,000 people died from heat stress in Europe, and in 2010, 56,000 deaths were recorded during a prolonged 44-day heatwave in Russia (Haines, 2021). In Victoria, Australia 374 deaths were recorded due to heat stress-related conditions in 2009 and it is considered that heat waves kill more Australians than any other natural disaster (Mansour, 2021). A recent study conducted by Rutgers University also found that heat stress may affect more than 1.2 billion people annually by 2100 (Dawei Li et al, 2020).
Exposure to extreme heat reduces working capability, especially for people involved in outdoor activities. The International Labour Organization (ILO) predicts that by 2030, 2.2% of working hours worldwide, or 80 million full-time jobs, will be lost as a result of higher temperatures. The rise of temperature and prolonged heat wave events can also impact the agricultural sector as drought conditions prevail and access to safe WASH facilities deteriorates, leading to an outbreak of fatal diseases.
South Asia, a densely populated area is considered to be a “hotspot” for heatwave related incidences. The Indian Meteorological Department (IMD) states that from 1979-2017 the extreme combination of both heat and humidity has doubled in many parts of India, Bangladesh, Pakistan, and Sri Lanka. Besides, it is also projected that by 2100 the average temperature will rise to 3-6C. This rising temperature will result in extensive heat wave conditions which can potentially affect 800 million people in the region. The IPCC regional report also provides similar prediction and projects a high potential for deadly heat waves to become a regular phenomenon in the South Asian region even if global warming is limited to 1.5C (IPCC, 2021).
For the last few decades’ scientific evidence and long-term, climatic records indicate an increasing trend in the frequency and duration of extreme temperature events all over Bangladesh. The North-Western part of the country is particularly vulnerable to heatwaves. A recent study finds +0.012C per/year and +0.370 day/year rate of the increase in annual mean temperature and seasonal dry days, respectively, from 1981 to 2016 in Rajshahi the North-Western part of the country (Karmakar, 2019). The Bangladesh Meteorological Department (BMD) also reports a significant increase in both maximum and minimum temperature over the last 21 years from 1990 to 2010 than in the last 63 years from 1948 to 2010 across the country (Hasan & Rahman, 2013). These heatwave events are affecting the health and livelihood of the people.
In 2003, 62 deaths were recorded from extreme heat (Rajib et al., 2011), and the death toll extended to 3800, in 2008 when eight-day prolonged heat stress occurred in the country (Gawthrop, 2017). ILO predicts that Bangladesh may lose 4.84% of the total working hours due to heat stress resulting from global warming by 2030 (ILO, 2019). With higher temperatures the scenario is likely to worsen in the major cities like Dhaka, Chittagong, and Rajshahi due to rapid urbanization and “Urban Heat Island Impact” (Dewan et a., 2021). Thus, it has become crucial to develop immediate action plans and respective national and municipal policies to address the heat stress impacts on human well-being and livelihood in Bangladesh.
Heat-related deaths and associated risks can largely be prevented by taking some measures. The WHO has already issued public health guidance for the general public and medical professionals on coping with extreme heat (WHO, 2018). To reduce heat-related deaths and associated risks India has introduced the HEWS (Heat Early Warning System) in Ahmedabad (Nissan et al, 2017). Bangladesh can consider taking similar interventions for the major cities in the country such as Dhaka, Chittagong, Rajshahi, and Khulna.
Additionally, the introduction of the Heat Adaptation Plan (HAP) at the city and administrative level, capacity building of the institutions, mass awareness, and knowledge campaigns, and infrastructural and technological development can enhance the overall understanding as well as facilitate necessary measures to tackle the impacts of heat waves in Bangladesh.
Originally this article was published on May 17, 2022 at Dhaka Tribune.
Savio Rousseau Rozario is currently working at the International Centre for Climate Change and Development (ICCCAD) as a Junior Research Officer. He holds a great interest in disaster risk reduction and management practices in terms of climate change impact. He can be reached at [email protected]. Dr Ali Mohammad Rezaie is an Assistant Professor at the University of Asia Pacific. He can be reached at [email protected].