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Why tropical forests are crucial to beat air pollution

The focus for World Environment Day 2019 is to beat air pollution. Image: Pixabay
The focus for World Environment Day 2019 is to beat air pollution. Image: Pixabay
The focus for World Environment Day 2019 is to beat air pollution. Image: Pixabay

Daisy Payne

Deforestation-free supply chains are important in tackling climate change, but did you know they could also be a solution to beat air pollution?

When we think of air pollution, our minds conjure images of smoggy cities, traffic-clogged streets and chimneys emitting noxious plumes. But air pollution is not just a problem for city dwellers. Findings from the World Health Organisation (WHO) show that 9/10 people worldwide breathe polluted air. The main cause of air pollution, like climate change, is the emission of harmful particles produced from burning fossil fuels. These can cause pulmonary and cardiovascular diseases, which lead to the estimated premature deaths of 7 million people each year, mostly in low-income cities.

Urban Jungles — a solution to air pollution?

Cities around the world have turned to nature-based solutions to combat air pollution: planting trees and creating urban green spaces to improve airflow and filter out particulate matter (PM) — one of the most lethal air pollutants. While this helps address rising levels of pollution within cities, it does not remove the problem. Like climate change, air pollution is a global, borderless problem that requires a multi-faceted solution both at the local, national and global scales. Planting trees in cities and cutting fossil fuel consumption are possible solutions, but what can be done at a global scale?

The lungs of the planet

“One breath in every five we take comes to us from the Amazon.”

Andrew Mitchell, Global Canopy Founder

Single trees are important, but when maintained as intact swathes of rainforest, they are an almighty force with the capacity to impact global air, water and nutrient cycles. As trees within tropical forests transpire during daylight hours, they release large amount of moisture and oxygen into the atmosphere. This helps drive the atmospheric circulation cycles which move oxygen and freshwater around the planet.

At the same time, tropical forests draw in and store carbon dioxide and other harmful air pollutants through their leaves, acting like gigantic air purifiers for the whole planet.

Bands of freshwater are generated from tropical forests in the Amazon, Congo Basin and Southeast Asia. Source: NCAR vislab

Loss of forests intensifies air pollution

Without rainforests, the ability to filter air and remove carbon dioxide from the atmosphere is at risk. Although not as lethal as PM, carbon dioxide is the most abundant pollutant in the Earth’s atmosphere. It also contributes to the greenhouse effect and in turn, this intensifies the harmful effects of air pollutants such as PM. Land use change and deforestation are the second largest human source of carbon dioxide globally. So clearing tropical forests not only removes the benefits of air purification but also creates a warmer environment that exacerbates the effects of lethal air pollutants.

The world’s tropical forests are being cleared to make way for agricultural expansion to produce a handful of commodities such as soy, palm oil and beef. According to Trase, the platform created by Global Canopy together with the Stockholm Environment Institute to explore the supply chain links for forest-risk commodities, soy traded from Brazil between 2006–2017 was associated with nearly 2 million hectares of deforestation risk. This forest loss in soy-producing areas generated approximately 325 million tonnes of CO2. This is the equivalent of burning approximately 32 billion tonnes of diesel. Deforestation contributes to a warmer planet while leaving less trees to filter air.

Solutions to air pollution

How do we protect tropical forests that could be as far as half a world away?

Governments and companies need to recognise and address the deforestation risks in their supply chains. Trase maps the flows of forest-risk commodities such as beef, palm oil and soy from the point of production, through the trading companies to the place of import, allowing companies to identify sourcing areas and see whether those areas are associated with deforestation or other social risks. Governments can use the data to help inform jurisdictional-level solutions and policies to tackle deforestation.

Companies first need to assess their exposure to forest-risk commodities such as palm oil, beef and soy. And then they can put commitments in place with a clear, time bound action plan to address those risks and remove deforestation from their supply chains. They should report on their action, ensuring that their suppliers also comply.

Consumers can also put pressure on companies to commit to zero-deforestation through their purchasing decisions. We are all part of the deforestation economy.

Air pollution and climate change are two of the gravest threats faced by humanity. Rainforests are nature’s lifeline to combat both; we all need to catch on before it is too late.