In the 1950s, when scientists of south Norway and western Sweden noticed that the fish in the lakes and rivers were dying or disappearing, they detected that the phenomenon was linked to the effects of acidifying air pollutants that had come in from afar.
In contrast, failing miserably to detect the reason for increased intensity of lightning strikes across the country, Bangladeshi scientists and academics are taking refuge under a few magic words-'global warming', 'climate change', 'deforestation',' population rise' etc. to explain the worsening conditions of the calamity.
According to another brand of experts, the recent increase in the rates of lightning can be attributed to what they call, 'the silent disappearance of Mouja Border pillars installed by the British rulers in south Asia'. According to them, these border pillars had 'dual purpose of demarcation of administrative area and absolve spark of thunder'.
In fact, what is actually believable is the increase in pollution which has, in turn, increased the rate of lightning strikes in the country.
A TALE OF TWO SPECIES: Pollutants were identified as the cause of deaths of fishes in the rivers and lakes of Sweden and Norway in the 1960s, a decade after it was first detected.
But the death of about 2,300 people by lightning strikes, in less than a decade, has not been enough for experts in Bangladesh to identify the causes behind the increase in lightning bolts.
National dailies quoting Disaster Forum, a Dhaka-based national disaster preparedness network, reported 2029 deaths in lightning strikes across the country from 2010 until 2017. As 200 people were reportedly killed this year until May 18, the casualties from the disaster now stand at around 2300 in less than a decade.
The government in 2016 declared lightning strike a 'natural disaster' as thunder bolts and casualties from it continued to rise. A compensation of Tk 20,000 was announced for family of anyone killed by the natural disaster. Reports published in the newspapers, however, do not mention any relief package for the injured of lightning disaster.
According to studies and newspaper reports, over 90 per cent casualties of lightning strikes take place in rural areas. A sharp increase in the casualties has been marked since 2010. But such incidents have been on rise since 1981, as reports have revealed.
But can a compensation package of Tk 20,000 really help the family of a victim? Taking into account all relevant expenses related to burial of a lightning casualty, one may question how much money the family is left with from the compensation amount for its sustenance and for how many days.
Compensation package for the family of lightning casualty is likely to be raised to Tk 200,000, some dailies have claimed while not mentioning a specific time from when it would be executed.
POLLUTION KEY TO ENHANCED LIGHTNING STRIKES: Professor Murad Ahmed Farukh, who heads the department of environmental science at the Bangladesh Agricultural University in Mymensingh, said, "Pollution plays a key role in enhancement of all sorts of lightning activity." "Surface pollutants have a close association with cloud to ground (CG) lighting activity," he added.
After analysing the pictures and information that he has access to on thunderstorm genesis, lightning flash and movement of thunder cloud from MODIS (Moderate Resolution Spectro Radiometer), he found that the upper atmosphere over Bangladesh gets warmer for a period of about four to six weeks from late April, especially when the dry season ends.
Farukh has 13 international publications to his credit of which four are on different aspects of lightning in Alaska and two are on Mongolia. Talking about his work on lightning in the country he said two of his research reports on thunderstorm occurrence and lightning trend in Bangladesh are in the process of publication in the international journals. He has been working on the issue here since 2016.
He explained, "When the dry season ends, moist and hot air from Bay of Bengal on the south, intrudes and intermingles with cold and dry air from the Khasi hills of Meghalaya and the Himalayas in the north of Bangladesh. Intermingling of the two air masses with opposite characteristics at the upper atmosphere creates a very unstable situation which is favourable for thunderstorm formation."
Characteristically air masses move around, but the hot air mass over Bangladesh during late April becomes stationary, deviating from its usual behaviour pattern. What contributes to this change? Do pollutants contribute and how? Are these pollutants local or transboundary or is it a cumulative effect of both?
A story in an English-language weekly in October last year quoting various scientific studies from across the globe questioned the contribution of pollutants in the increased lightning strikes in Bangladesh.
According to that article, Indian emission of "both Sulphur dioxide (SO2) and Nitrogen dioxide have increased, particularly over the northeast", where "a large number of newly-built coal power plants have doubled Sulphur dioxide while increasing Nitrogen dioxide (NO2) by 50 per cent ... India's total annual SO2 emissions almost doubled from 6.7 Tg in 2005 to estimated 12 Tg in 2014. Unlike the US, Europe, and China, SO2 and NOx emitted from coal-fired power plants are not regulated in India and the installation and operation rates of SO2 and NOx emission control devices are very low."
The coal-fired power plants in India are neither regulated nor there exist any adequate measures to reduce these emissions.
When the professor's attention was drawn to the story and he was asked about the contribution of local or transboundary pollutants in the increase of lightning strikes in Bangladesh, he said, "no such study has been conducted yet".
"Upper atmospheric situation in terms of pollution over Bangladesh is worsening every day," he observed, adding that the concentration of some primary air pollutants like Nitrogen Oxide, Ozone, Sulphur dioxide and suspended particulate matter over Bangladesh, needs to be analysed to ascertain their adverse influence on lightning trend.
"Pollution plays a key role in enhancement of all sorts of lightning activity," the professor said, stressing, "Surface pollutants have a close association with cloud-to-ground (CG) lightning activity".
"The influence of atmospheric pollutants on cloud systems directly affects radiation budget and indirectly affects the cloud dynamics and microphysical properties. Atmospheric pollutants play a crucial role in the various development stages and formation of local weather system," he said.
A recent study done in Taipei, Taiwan from 2005 to 2010 reveals that high frequency weather phenomenon like lightning activity are not only influenced by meteorological parameters but also influenced significantly by tropospheric particulate matters. Other surface pollutants like oxides of nitrogen (NOx) and ozone (O3) also show strong linear association with CG lightning flashes.
He pointed out that study on contribution of sulfur dioxide (SO2) to the increased lightning activity in central Spain while a positive correlation between particulate matter 10 (PM10) concentration and CG lightning over southern Brazil has been proven. Moreover, enhanced surface pollution in a near-storm environment is strongly related to the increased lightning activity, he said.
"The suspended particulate matter (SPM) concentration at surface level is supposed to affect the lightning flash rate during pre-monsoon season in Bangladesh. Higher SPM concentration (>160µgm?3) corresponds to higher lightning flash rate irrespective of the cloud base formation as stated by many researchers for many lightning prone areas," said Farukh.
"Additionally, SO2 is more strongly associated with CG lightning activity compared to PM10 concentration. Results from various studies indicate that the NOx concentration on days with lightning activity is twice more than the non-lightning days while the O3 concentration is increased by 1.5-fold. Such increase in NOx and O3 concentration on days with lightning strongly supports the transport phenomena of NOx and O3 from the upper or middle troposphere to the lower troposphere by downdraft of the thunderstorm during its dissipation stage," he said.
"Effect of aerosol in thundercloud formation process and consequent rainfall is also important. Trenberth et al reported how aerosol can effectively modify our weather system in 2000," said Farukh.
A new generation of ground-based, airborne, and space-based sensors equipped with monitoring devices connected with new satellite imaging systems has been developed in the past few years. According to Dr Rashnal Hossain, a lecturer at ZH Sikder University of Science and Technology in Shariatpur, these have opened new vistas of opportunities and understanding of the environment around us.
Such "development in the field of atmospheric science during the past few decades have equipped scientists, with sufficient knowledge that pollutants contribute towards changing the behaviour pattern of various elements in the atmosphere," he said.
When lightning strikes, pollutant gases in atmosphere become conductor or attract the charge of the lightning strike towards the surface of the earth, said Rashnal.
When asked about the role of the magnetic border pillars at reducing lightning fatalities, Rashnal said that there is no scientific basis in favour of the claim that besides demarcation the pillars were neutralising the impact of lightning strikes. These are usually buried under earth, he noted.
Those who claim that removal of the pillars contributed to the increased CG lightning in the country should at least provide a chemical analysis of the constituent of the pillars, demanded Rashnal.
A QUIXOTIC SOLUTION GOES INTO EXECUTION: To reduce the lightning damages, the government has already planted 3.164 million (31 lakh 64 thousand) palm seeds across the country. This move was driven by the statement of experts that tall trees attract much of the lightning in flat plains.
Palm trees take seven years to grow from seeds to trunk. Over the next 10 years, there is rapid upright growth of one to 2.0 feet a year. This growth slows to an average of one to three inches a year.
It will take more than 10 years for these trees to reach a height that will attract the lightning bolts. During this time, more lives are likely to perish from the bolts.
In another development, government has recently installed eight sensors capable of early warning on incidents of lightning. The sensors procured from the USA at a cost of about Tk. 200 million (20 crore) have already been installed in Dhaka, Chittagong, Sylhet, Khulna, Panchagarh, Naogaon, Mymensingh and Patuakhali. The system now under experimental operation will be inaugurated by the end of the year.
The sensors can provide accurate detail about location and time of thunderbolts. But the forecast can only be received by a cell phone compatible to download the app BMD weather.
This begs the question, how many people from rural Bangladesh have smartphones and can use these apps in order to take full advantage of the forecasts from the sensors? The number is likely to be very low.
Then, is it right that millions of takas are being spent from state exchequer to procure equipment and devices but their services at the receivers are made available to only those who have some specialised gadget at the receivers end?
Determining the true causes of lightning bolts is of utmost importance for concerned authorities. And this can be accomplished through appropriate research by scientists who have experience in the field. The cause should then help at strategising the solutions.
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