Fires could turn the Amazon rainforest into a desert as human activity and climate change threaten ‘lungs of the world’, according to scientsits.

It’s been a bad year for the Amazon, which is the largest rainforest in the world, a vital carbon store that slows down global warming, and an area that almost never burns on its own thanks to its natural moisture and humidity.

That has changed and thanks to the growing number of wildfires it has become a bigger emitter of CO₂ than the US, making it the third biggest source of emissions in the world. Reuters reported that there have been a record number of fires this year in the Amazon, according to new data released by the National Institute for Space Research (INPE), based in Brazil.

The Amazon rainforest is becoming increasingly vulnerable to catastrophic forest fires due to a combination of droughts, climate change and human activities such as deforestation, farming and habitat fragmentation, a major study has concluded.

"The planet's tropical forests are being destroyed at a rate of thirty soccer fields per minute, with catastrophic consequences for all life on Earth," says Ben See, a commentator on Radio Extinction. "Tropical rainforests may be nearing a tipping point beyond which deforestation will spiral out of human control, a shift from human-caused destruction to self-collapse, as forest fragments shrink and die due to their inherent instability.”

Brzail's fires are now large enough to be seen from space. As temperatures inextricably rise, wildfires are becoming an increasingly large problem and have already turned trees into a net emitter of emissions from a carbon sink in the last few years.

The 1.5C-2C rise in temperature goal of the Paris Agreement has already been missed and the world is on course to warm by 2.7C-3.1C by 2050 in the best case scenario. If temperatures reach 3C then the permafrost will almost completely disappear, releasing 1,000 gigatonnes of primordial CO₂  -- twice as much CO₂  than humanity has created since the dawn of history – that could trigger run away global warming say scientists. With a 4C increase in temperatures, which current models predict will arrive sometime in 2075-85, some 85% of the Amazon rainforest will disappear. Even modest temperature rises in the meantime will lead to 20-40% of the forest disappearing, according to a study carried out by the British Met Office’s Hadley Centre.

One of the last great wildernesses on earth – known as the lungs of the world – is balancing dangerously close to a “tipping point” where forest fires will become so commonplace and extensive that they will change much of the landscape forever, scientists said.

 

Although fires have always occurred in Amazonia, they have been largely controlled by the natural humidity of the region. Now, however, the drying out of the rainforest threatens to ignite the tree-filled habitat – with its rich biodiversity – and convert it almost overnight into barren desert, scientists warn in a new study published in the journal Proceedings of the National Academy of Sciences, The Independent reports.

For the first time, scientists have shown in a series of experiments on the ground and making use of satellite data how extreme, dry weather combined with the effects of human activities creates a “tinderbox environment” where intensely damaging forest fires can spread easily, killing trees and releasing their carbon that has been locked up for hundreds of years in one go.

The study, carried out on three large experimental plots of rainforest monitored by satellite, showed that droughts abruptly increased the risk of intense forest fires compared to non-drought years, and this effect can be exacerbated significantly in areas influenced by human activities.

“These results provide, to our knowledge, the first experimental evidence of the link among extreme weather events, widespread and high-intensity fires and associated abrupt changes in forest structure, dynamics and composition,” said the scientists from the US and Brazil cited by The Independent.

The researchers monitored the three 50-hectare plots of Amazon rainforest over an eight-year period. During this time they subjected two of the plots to controlled fires, either on an annual or a three-year basis, and left the third plot untouched as a control for comparison.

They found that while the rainforest did not burn very much in years with normal rainfall, it burned intensively and extensively in drought years, which are expected to increase in both frequency and severity due to climate change causing shorter, more intense rainy seasons and longer dry seasons.

Trees in the tropical rainforests, unlike more temperate woodlands, are not naturally immune to forest fires and are easily killed by flames. The study found that this vulnerability caused a collapse of the overhead canopy cover and an invasion of the forest by more flammable vegetation from the inhabited forest edges, causing a cascade of events that increased the chances of an irreversible “tipping point” triggered by fire.

In Brazil the dangers have been exacerbated by intense logging to clear more forest to create more agricultural land. Brazil’s track record on halting deforestation has also come under renewed scrutiny. The country has lost around 17% of its forests since the 1970s—driven by cattle ranching, soy cultivation, and illegal logging. Between 2001 and 2020, the Amazon lost over 54.2mn hectares, or almost 9% of its forests, an area the size of France. Government efforts to stem the pace have largely been ineffective, as enforcement agencies remain underfunded and policy rollbacks under previous administrations weakened key environmental protections.

Agricultural development has fragmented the forests, say experts, that are more likely to be invaded by flammable grasses, which further increase the likelihood and intensity of future fires.

The researchers emphasised that most computer models of how the Amazon will respond to climate change do not take into account the true scale of the threat posed by forest fires, which is a serious flaw in the assessment of what could happen over the coming decades of warmer global temperatures.

The new study shows that fires are already degrading large areas of forests in southern Amazonia and highlights the need to include interactions between extreme weather events and fire when attempting to predict the future of Amazonian forests under a changing climate, scientists say.

Rising temperatures are already increasing the risk of wildfires. Over the last decade years, the Amazon has experienced a series of unusual droughts that has seen the level of the river drop to the point where only mudflats are left on some occasions. In 2005, the drought was so severe it was dubbed a one-in-100-year event. But an even more extensive drought followed on in 2010.

On both occasions, scientists believe the Amazon went from being a net absorber of carbon dioxide to a net emitter: during the 2005 drought the forest went from previously absorbing of about 2bn tonnes of CO2 to emitting as much as 5bn tonnes of CO₂ – almost as high as the 5.4bn tonnes emitted annually by the US, the second biggest emitter of emissions in the world.

The damage done by the 2010 drought was even worse. The massive Rio Negro river – the biggest tributary of the Amazon – saw its water level fall to its lowest level since record began more than a century ago. On that occasion, the forest expelled some 8bn tonnes of CO₂, scientists said.

A more regional drought in 2007, which mainly affected southeast Amazonia, caused a significant increase in forest fires in the area, which burned about ten- times more forest than in typical years – an area equivalent to a million soccer fields.

The scientists believe that the findings show that the response of the Amazon to rising global temperatures and the increased risk of severe drought years can be unpredictable and “non-linear” because of a sudden breach of an irreversible tipping point.