The Pros and Cons of Cleaning Air Pollution

While air pollution is a big problem internationally, its effects are particularly evident in India and Southeast Asia, where rainfall has become irregular and unseasonal. For approximately five decades, the summer monsoon seasons in India and Southeast Asia have been affected by polluted airborne particles, which hinder rainfall and can lead to drought. However, as nations strive to reduce air pollution levels, rainfalls are likely to increase, causing a raft of new problems, such as flood damage to roads and agriculture, disease, death and displacement across the subcontinent. In this article, we look at the pros and cons of cleaning air pollution in a little more detail.

The importance of the monsoon

Across India and Southeast Asia, millions of people depend on the monsoon seasons, which represents their main source of water. Yet for more than fifty years, rainfall levels have declined, alarming farmers and impacting upon crop maturation. Initially, scientists were unsure whether volcanoes, greenhouse gasses or climate variability were disrupting the monsoon seasons. Today, however, the majority of mainstream scientists agree that aerosol production is to blame and suggest we all strive to reduce the amounts of aerosols we produce.

Dr Debbie Polson, a climate scientist at the University of Edinburgh and co-author of a study on aerosols published in the journal Geophysical Research Letters, asserts: “research explicitly ruled out other explanations and showed that only anthropogenic aerosols could explain the observed changes”.

Aerosols disturb rainfall by blocking sunlight, reducing air temperature and hindering evaporation. Subsequently, the air contains less water than it otherwise might. When there is less water in the air, rainfall is less frequent, making crop irrigation more difficult and costly, which leads to poor harvests and economic hardship.

While too little water causes damage to crops and impacts upon many people’s livelihoods, too much water can be equally as devastating. Neither flooding nor drought will benefit local or global economies, while both can cause enormous hardship and loss of life.

Decreasing aerosol levels

Scientists predict that aerosol levels will decrease over the coming decades. And as aerosol levels decrease, rainfall is likely to increase, meaning monsoon rains may eventually exceed record levels. Naturally, excess rainfall can lead to flooding, loss of life and damage to infrastructure, so it’s important that flood provisions are made sooner rather than later.

Conversely, while global aerosol production declines, localised aerosol production in and around India and Southeast Asia remains relatively stable. Until localised aerosol production is reduced, it is difficult to say whether the monsoon seasons will alter dramatically. Since so many millions of people depend upon seasonal monsoons, any change in rainfall levels is likely to have a significant impact. 

Monitoring Changes to the Monsoons

For the last three years, Dr. Intan Suci Nurhati had gone on expeditions to islands off Singapore, Indonesia as well as Kuwait in search of large corals. On these expeditions, small samples of coral were collected to facilitate a range of subsequent geochemical analyses, such as: What are the changes to the monsoon over the past century? You can read about this topic at: Corals as Natural Archive of Environmental and Climate Changes.