Bangladesh has experienced an extra 57 days – almost two months – of extreme heat over the last 12 months due to climate change.
From May 15, 2023, to May 15, 2024, Bangladesh faced almost 76 days of extreme heat, which is hotter than 90% of local temperatures recorded in a 30-year period, said a report.
In stark contrast, without the influence of climate change, this number would have been just 19 days,
This means the country witnessed a staggering four-fold increase in extreme heat days, directly linked to human-caused climate change.
The information was revealed in a study by World Weather Attribution, the Red Cross Red Crescent Climate Centre, and Climate Central, where scientists used the years 1991 to 2020 to determine what temperatures counted as within the top 10% for each country over that period.
Next, they looked at the 12 months to May 15, 2024, to establish how many days over that period experienced temperatures within – or beyond – the previous range.
The report identified 76 extreme heatwaves across 90 countries, exposing billions of people across the world to dangerous conditions. Regions such as South and East Asia, and parts of South America were notably affected.
The findings of the study pointed out the urgent need for immediate climate action in Bangladesh, which is highly vulnerable to escalating heat risks.
Escalating heat risks in Bangladesh
Bangladesh, a densely populated nation already grappling with various climate-related challenges, now faces heightened risks from intensified heatwaves.
Dr Muhammad Abul Kalam Mallik, a seasoned meteorologist working at the Bangladesh Meteorological Department (BMD), recently told Dhaka Tribune that for the past 10 years or so, the duration of heatwave days has been increasing in Bangladesh.
In a recently published scientific journal paper, Dr Mallik and his co-authors analyzed heatwaves of the 1990-2019 period to show that Jessore, Chuadanga, Rajshahi, Ishwardi, and Satkhira have been experiencing the highest numbers of heatwave days (20 to 30 days) during the pre-monsoon period (from March 1 to May 31).
Their study found that Bangladesh's capital, Dhaka, also experiences an average of 8.5 days of heatwaves during the pre-monsoon months.
He said: "April is the hottest month in Bangladesh, and the country experienced 17 heatwave days in April last year.”
Bangladesh also experienced several days of heatwave throughout the month of April, he added.
Recently published BMD report "Changing Climate of Bangladesh" observed that the minimum and maximum temperatures increased in the country but the maximum temperatures increased more rapidly.
In recent years (2018-2022), Bangladesh has experienced a 0.9℃ rise in its summer temperature relative to the 1986-2005 baseline. That is 0.2℃ higher than the global average increase in summer temperatures.
According to the 2023 Lancet report "Countdown on Health and Climate Change," only Afghanistan (1.3℃) in South Asia has witnessed a higher temperature rise than Bangladesh.
What do experts say?
Climate expert Dr Ahmad Kamruzzaman Majumder, chairman of the Department of Environmental Science at Stamford University Bangladesh, told Dhaka Tribune: “Historical data from the Delta Plan indicates a temperature increase of slightly more than 1°C over the past 30 to 40 years in Bangladesh. However, recent summers have experienced more dramatic heat patterns, with temperatures rising by 2°-5°C in both urban and rural areas.”
Pointing out the reasons behind this alarming trend, Dr Kamruzzaman said urbanization has led to changes in land use, reducing reservoirs and greenery while increasing vehicular traffic and air conditioning usage.
He emphasized that the perceived temperature, which is what people actually feel like, poses a greater health concern than the actual thermometer readings.
Dr Kamruzzaman, who is also the founder and director of Center for Atmospheric Pollution Studies (CAPS), said: "Increased humidity leads to discomfort and perceived temperatures that can be 5°-10°C higher than the actual temperature," he explained.
Looking to the future, he warned of the dangerous trend of decreasing agricultural land by 1% annually, replaced by urban buildup. "This shift not only reduces cooling factors but also amplifies warming factors, potentially accelerating desertification," the professor said.
Two previous World Weather Attribution studies found that human-induced climate change influenced extreme heat in Bangladesh and several other South Asian countries, making them around 30 times more likely and much hotter.
He stressed the urgent need for collective action, including tree planting and reservoir conservation, to combat land degradation and mitigate the impacts of rising temperatures.
"We all have to work together. Planting trees across the entire country is not something the government can achieve alone. Common people must come forward and work together to prevent land degradation and conserve reservoirs," Dr Kamruzzaman urged.
Global context
Globally, extreme heat is among the deadliest natural hazards, with thousands of people dying from heat-related causes each year.
The continuous burning of coal, oil, and gas has released enough greenhouse gases to warm the planet by 1.2°C since pre-industrial times, leading to more frequent and intense extreme weather events, with heatwaves being the most dramatically affected.
Over the past year, an astounding 6.3 billion people, or approximately 78% of the global population, experienced at least 31 days of extreme heat.
This level of heat, hotter than 90% of local temperatures recorded from 1991 to 2020, was made at least twice as likely due to human-induced climate change.
On average, human-caused climate change added 26 days of extreme heat globally over the past year compared to a scenario without a warming planet.
Alarmingly, 2023 was Earth’s hottest year ever recorded, beating the previous record set in 2016 by a huge margin. The world was close to 1.5°C (1.48°C) hotter than the pre-industrial average (1850-1900).
Some scientists, including former Nasa climatologist James Hansen, predict 2024 will be humanity’s first year beyond 1.5°C.
“If humanity wants to have a 50-50 chance of limiting global warming to 1.5°C, we can only emit another 250 gigatonnes (billion metric tonnes) of CO₂,” said climate and atmospheric scientists Chris Smith at the University of Leeds and Robin Lamboll at Imperial College London. “This effectively gives the world just six years to get to net zero.”