Wildfires raging in the Amazon rainforest have hit a record high this year , with Brazil's space agency claiming to have detected 72,843 so far.
The surge marks an 83% increase over the same period of 2018, and is the highest since records began in 2013.
Most of the fires are in the Amazon basin, which is home to about three million species of plants and animals, and one million indigenous people.
The rainforest is known as the the "lungs of the planet" because it provides the vital role of absorbing carbon dioxide, and produces more than 20% of the Earth's oxygen.
But a new report suggests that increasing wildfires threaten to turn much of the planet's forests from vital carbon stores into climate heaters.
According to the study, published this week in the journal Nature , wildfires release vast amounts of carbon dioxide (CO2) into the air and temporarily prevent carbon from accumulating in the trees and soil.
As part of the natural carbon cycle, the lost carbon is stored again by new trees, which use CO2 from the air to grow, as well as by the dead plants, leaves and branches that accumulate in the soil.
It can take many decades until all the carbon that was emitted during a fire is recaptured by the ecosystem but, as long as the time between two fires is longer than the time required to recapture that lost carbon, forests remain a carbon sink.
However, scientists warn that climate change is shortening the interval between fires, leaving less time for forests to regrow.
It is also increasing the intensity of individual fires, allowing them to burn deeper into the soil.
"These factors mean that more and more of an ecosystem on which we rely so much to remove carbon from the atmosphere could soon fall on the opposite side of the carbon ledger," scientists from Swansea University wrote in an article for The Conversation .
While the study looked specifically at the northern boreal forests of Canada, which punch well above their weight as carbon sinks, wildfires can have a similar effect on all forests.
The Amazon rainforest absorbs around a quarter of the CO2 released each year from the burning of fossil fuels, so it plays a critical to help mitigate climate change.
A separate report , published in the journal Nature Geoscience last week, claims that the Amazon rainforest is absorbing less carbon than expected, due to insufficient nutrients supply in the soil.
With the recent spate of wildfires effectively releasing a carbon dioxide bomb into the atmosphere, there's a danger that much of the forest's vital work could be reversed.
