From the vast Amazon rainforest that unfurls across nine South American territories to the tropical forests that shelter mountain gorillas in the Democratic Republic of Congo and orangutans in Indonesia, forests are key to human life.
But these rich resources are under threat from deforestation driven by mining, land-grabbing, animal grazing and deadly wildfires. And that’s bad news for humans and the planet as rainforests are key to reining in runaway climate change.
With the United Nations warning that the battle to limit global warming will be won or lost in the 2020s, here’s why rainforests need to be protected:
Why are rainforests crucial for the planet?
Tropical rainforests encompass around 1.2 billion hectares (3 billion acres) of vegetation and they are one of the world’s largest stores of planet-warming greenhouse gases because trees absorb huge amounts of carbon dioxide and release the oxygen humans need to live.
That means that forests act as carbon sinks and remove about 7.6 billion metric tonnes of CO2 each year from the atmosphere, which is around one-and-a-half times the average annual emissions of the United States.
But if too many trees die and rot, forests become net carbon emitters and can accelerate climate change. This destruction also imperils biodiversity because of how many plant and animal species call forests home.
During a devastating drought in 2005 in the Amazon, the world’s largest rainforest, so many trees died that the forest emitted more greenhouse gases than Europe and Japan’s annual emissions, according to research published in 2009.
Rainforests play a key role in the water cycle. The forests’ dense canopies hold moisture and feed water vapour back into the atmosphere, driving further rains.
This is critical in South America, sub-Saharan Africa and the islands of Southeast Asia. By maintaining stable rainfall patterns and temperatures, rainforests are vital for food and water security.
About 1.6 billion people, including nearly 70 million Indigenous people, rely on forest resources for their livelihoods.
Forests can also act as buffers against natural disasters as canopies can intercept rainfall and slow it down in a storm, protecting the soil underneath.
Are rainforests facing a tipping point?
Tipping points happen when a small change - such as an incremental increase in global temperatures - sparks a rapid, often irreversible transformation, scientists say.
Forest clearances and global warming may already have pushed the Amazon close to a tipping point that could see the lush forests transformed into savannah in coming decades, according to scientists.
When humans degrade rainforests by removing trees, sunshine beams down through the thinned canopy, altering the temperature and conditions of the rainforest ecosystem.
In 2018, leading climatologists Carlos Nobre and Thomas Lovejoy estimated that between 20 per cent and 25 per cent of the Amazon forest must be kept intact to prevent portions of it from turning into a drier savannah-like ecosystem.
Over the past two decades, the Amazon rainforest has become slower at recovering from longer periods of drought, damaging its complex ecosystem and pushing it closer to a possible tipping point, according to study published in the journal Nature Climate Change in 2022.
The research showed that three-quarters of the rainforest has been losing its ability to recover from shocks, such as droughts and fires, and return to a healthy state.
Tipping points might already have been reached in parts of Brazil’s southeast Amazon region, with some areas now emitting more planet-heating carbon than is absorbed, according to research published in the Nature journal in 2021.
What drives deforestation?
Cutting down trees to clear land for agriculture, including small-scale farming, and grazing drives global deforestation.
In the Amazon, home to about half of the world’s remaining tropical forest area, most deforested land is used as cattle pastures, followed by soy fields. In Brazil, the world’s second biggest beef supplier, cattle herds are increasingly fed on pastures deforested in the Amazon.
Another key driver of deforestation in the Amazon is land-grabbing carried out largely by organised crime gangs. The damage being done to the rainforests in Colombia, Peru, Brazil and Bolivia has been described as “narco-deforestation“.
A growing body of research indicates that speculation within this illegal land market, not just food production, is key to deforestation.
Traffickers use drug profits to buy forest land - sometimes illegally speculating or else legally buying forest - that is then turned into cattle pastures.
Illegal gold mining is another major driver of deforestation across the Amazon.
In Peru and Colombia, the clearing of trees to grow coca, the raw ingredient for cocaine, also drives deforestation.
In Indonesia, home to a third of the world’s rainforests, deforestation has been linked to clearing land to produce palm oil. The country is the world’s biggest palm oil producer and exporter.
Tropical forests are also increasingly prone to destructive wildfires as global warming leads to the hotter, drier conditions that fuel bigger blazes.
Where is tropical forest being lost and protected?
Globally tropical forest loss declined last year - by 9 per cent when compared to 2022 - but the destruction of the world’s rainforests still remains stubbornly high, according to research published by Global Forest Watch in April.
In 2023, the loss of primary forests - those untouched by people and sometimes known as old-growth forests - totalled about 37,000 square km (14,000 square miles), an area nearly as big as Switzerland and larger than the US state of Maryland.
