22 Jan, 2021

The Pollution-Migration Link and its Repercussions on Food and Agriculture

by Alessandro Balduzzi

1. Although largely neglected, the link between air pollution and migration is all but secondary. Both are transnational phenomena that do not know any boundaries, and both have been gaining prominence in the last years.

Their interconnected importance has been recently stressed by a landmark ruling by a French court which is believed to be the first quoting air pollution as playing a role in an extradition hearing. The hearing involved a Bangladeshi man with asthma who risked being deported to his homeland. His lawyer, though, was able to persuade the appeals court in Bordeaux to overturn a previous expulsion order in light of severe deterioration of his health condition that he would have risked once in Bangladesh.

According to Yale and Columbia universities’ 2020 environmental performance index, the Asian country ranks 166th out of 180 countries for air quality. Moreover, the concentration of fine particles in the air is six times the World Health Organization’s (WHO) recommended maximum.

The aforementioned ruling must be regarded as a milestone since it states that a government (notably the French one) acts illegally when returning people to countries where their lives might be threatened by climate crisis. The other side of the coin, ça va sans dire, is that the same people who cannot be sent back to their home country were forced to leave it also due to environmental degradation.

2. Air pollution causes around 7 million premature deaths every year, around one death every five seconds, according to the United Nations. It is estimated that 90 per cent of the world’s population breathe polluted air. Out of 7 million victims, around 600,000 are children. Furthermore, the most affected countries belong to the so-called developing world, being either low-income or middle-income countries.

Bangladesh belongs to this category and relies mostly on a highly polluting industry, which involves waste burning and toxic emissions from concrete, steel and brick plants - in addition to vehicle emissions due to the ongoing rapid urbanisation. Statistics from the Environmental Justice Foundation show that one in every seven people in Bangladesh will be displaced by climate change by 2050 and up to 18 million people may have to move because of sea level rise alone.

In addition, air pollution is striking neighbouring China as well, affecting the country’s migration dynamics. A study by S. Chen, P. Oliva and P. Zhang found that Chinese internal migration flows rise when air pollution surges too. Despite the strict programme of residential registration implement by Beijing authorities to curb people’s movement, migration happens regardless and mostly involves well educated people at the beginning of their professional life. In this case air pollution is not just as an environmental issue, but also an economic one that drains talent out of big, polluted cities.

A further study relates internal migration to an increase in mortality from air pollution exposure in Peru, where rural-urban migrants are one of the most vulnerable migrant groups. Last but not least, air pollution-migration link could not be a prerogative of underdeveloped/developing countries; in this respect, for instance, Italy is the object of an ongoing research to examine whether and how the decision to emigrate can be associated with air pollution for the sake of safe health conditions. The results will be doubtless noteworthy.

3. Up to this point, our focus has been on the link between air pollution and migration mainly through the lens of health issues.

Still, air pollution presents no less threat to food and agriculture. According to the UN Environment Programme,  ground-level ozone pollution created by fuel burning and chemical use will reduce staple crop yields by 26 percent by 2030. In addition, global food supply is also one of the five largest contributors to pollution. As a matter of fact, industrial agriculture led to both higher productivity and increased pollution. Smoke from slash and burn agriculture, and the production of silt, ash, and soil dust from activities like tillage, transporting, and harvest, contaminate the air with particulate matter.

Agricultural air pollution appears most drastically in the form of ammonia: emissions from livestock manure and chemicals make up 95 percent of total ammonia emissions. Furthermore, farmers resort more and more to pesticides, herbicides, and fertilisers. Last but not least, globalisation makes ever more important carbon dioxide-releasing activities like transportation, packing, and storing.

4. Whilst causing air pollution, modern agriculture risks committing suicide. If new means involving higher emissions guarantee rising yields in the short term, their toll on crops is felt in the long run.

“Yellowing”, reduced growth, injury, or outright premature crop death number among air-pollution linked negative effects. Yellowing is caused by nitrogen deficiency and occurs when short-lived pollutants and ground-level ozone interrupt crop development and photosynthesis, burning plant tissue and slowly depriving plants from sunlight and fresh air.

Moreover, air pollution considerably contributes to yield losses through an increase in ozone concentrations - which damages plant cells and negatively affects photosynthesis - and in particulate matter, which reduce the amount of sunlight that reaches plants and food crops.

Back in 2000, global yield losses due to ozone amounted to 79-121 million tons, including yield losses of up to 15% for soy and wheat, and 5% for maize. This type of pollution has caused massive damage to food crops in India, for instance, where the amount of wheat, rice and soy crops lost annually between 2000 and 2010 could have fed close to 94 million people.

Last but not least, air pollution causes temperatures to rise and can wreak havoc on crops worldwide: According to the FAO, crop yields of staples like rice, maize, and wheat will decrease by up to 10 percent per degree Celsius of global warming. Not to act for a cleaner atmosphere means putting at risk the global food supply, undermining both food security and subsistence agriculture especially in economies based on the primary sector. There, dirty air can be the straw that breaks the camel's back and lead to the decision to the decision to leave your land and migrate elsewhere once and for all.