Unfortunately, Bangkok's awful smog continues unabated -- PM2.5 levels daily reach unhealthy levels in many of the city's districts. The timing is inconvenient because research suggests there are increased rates of Covid-19 in areas with high levels of air pollution. A couple of weeks ago I wrote about how vehicular emissions is one of the major sources of Bangkok's air pollution.
However, another major contributor is biomass burning in the agricultural sector. In Bangkok, scientific estimates for biomass burning's contribution to the PM2.5 levels vary from 24 to 38%, with the majority of it coming from sugarcane and rice burning. Most of the burning which contributes to Bangkok's pollution comes from within Thailand, though a small portion likely originates from Cambodia.
Burning occurs in sugarcane production in a couple of ways. Farmers burn it to reduce the amount of leafy extraneous material, such as stalk tops. Also, after harvesting their paddies, rice farmers in the region routinely burn rice stubble, which is the residual plant material, in order to prepare fields for the next round of crops.
Sugarcane remains one of Thailand's most important crops, providing more than 1.5 million jobs and generating more than 180 billion baht per year in revenue. Thailand exports around 70-75% of its sugar production and ranks second globally in exports behind Brazil. Much of the sugar heads to other Asean countries due to low tariffs. The industry is competitive partly due to governmental support, such as the Cane and Sugar Act which introduced a quota and price support system and a distribution mechanism between growers and millers. Production is concentrated in the Central and Northeast regions, including in provinces nearby Bangkok.
However, a major negative economic externality produced by this industry is air pollutants -- wind patterns blow emissions from farms into Bangkok. Harvesting occurs from November to February which is when the city experiences its worst pollution. Burnt sugarcane is widespread, accounting for 60–67% of total production. Farmers state that they burn because it is cheaper and requires less labour and time than using harvesting machines. Mechanised harvesting is practised less than 10% of the time.
An Agricultural Promotion Department officer proclaimed, "A harvesting machine is very expensive. Most farmers are poor. They won't use it." Further, harvesting machines are in short supply so farmers often have to wait to use them. She also explained that it was laborious to manually cut the stems. Therefore, even if farmers received 15 baht less per one cubic metre for burnt sugarcane from mills, meaning that they receive 285 baht compared to 300 Baht for unburnt sugarcane, they still preferred to burn it because they make a greater profit and burning requires less time.
Further, since many farmers are locked into contract farming schemes, they feel pressured to deliver sugarcane on time to the millers. The time period for harvesting has also shortened because of climate change-induced droughts. The time pressure and the limited harvesting period further incentivise farmers to burn sugar as it is the quickest harvesting method. Even when the Ministry of Agriculture decreed a ban last year, numerous farmers circumvented it by burning their fields at night.
Besides weak state implementation of burning bans, a number of other factors impede curbing emissions in this sector. First, national agricultural policies have continued to promote the expansion of the sugarcane and rice industries through subsidies, quotas, extension services, and other measures.
Second, since 2012, many farmers, who have limited access to land, have become indebted to large agribusinesses due to falling prices diminished yields, and the reduction of initial government subsidies. Consequently, they feel pressured to continue to produce these crops in order pay off their debt and cannot afford to invest in technology or switch to more laborious methods which could reduce burning. The government, however, does not provide any solutions. According to a local NGO activist: "The government doesn't give any money or machines or labour."
Third, the government often complies with the requests of agribusiness companies and farmer groups who push the government to relax the percentage of burnt sugarcane which they can legally sell. This indirectly contributes to more burning.
Fourth, the government uses a single-command system to regulate the burning. Each province has a commander, the provincial governor, who has sole authority to deal with air pollution from agricultural burning. However, the problem with this system is it is slow and has limited levels of accountability -- all officials must wait for the governor's orders -- and nobody monitors the governors' performance.
Also, similar to the transport sector, widespread inequality in terms of those who profit and suffer the most from emitting air pollutants is deeply embedded in the agriculture sector too. The ones profiting the most from biomass burning are Thai agribusiness conglomerates, large sugarcane millers, and consumers but they do not have to pay for this externality or are blamed by the government or the public. Instead, impoverished, indebted farmers who themselves must bear the heavy costs of breathing in air pollutants are often cast as the villains.
The obvious, immediate but costly way to reduce burning would be for the government to subsidise or provide harvesting machines to farmers. Broader solutions are complex and difficult. I do not profess to know the best answers but potential ideas include moving away from monoculture production, the cultivation of a single crop in a given area, to agroecology practices, such as crop diversification and rotation; initiating land reform measures and breaking up agribusiness monopolies so that smallholder farmers can produce more and be less indebted; and, perhaps and controversially, reducing the role of agriculture in the economy. Nonetheless, what is clear is that continuing to uphold the status quo will not reduce air pollution in Bangkok and other cities.
Danny Marks is an Assistant Professor of Environmental Politics and Policy at Dublin City University.