Sharjah24 – AFP: Holed up in her lab, Brazilian atmospheric chemist Luciana Gatti crunches her numbers again and again, thinking there is a mistake.

But the same bleak conclusion keeps popping up on her screen: the Amazon, the world's biggest rainforest -- the "lungs of the Earth," the "green ocean," the thing humanity is counting on to inhale our pollution and save us from the mess we've made of the planet -- is now emitting more carbon than it absorbs.

Splashed across South America in an exuberant blob of deep green, the Amazon basin is one of the world's great wildernesses, a place where life teems in the heat of the tropics, fed by the myriad rivers criss-crossing the jungle like blue blood vessels.

Home to more than three million species, the rainforest bursts with lush vegetation, which absorbs huge amounts of carbon through photosynthesis -- a key fact as humankind struggles to stop heating the planet with greenhouse gases.

As carbon dioxide emissions have surged by 50 percent in 60 years, to nearly 40 billion tonnes worldwide, the Amazon has absorbed a large amount of that pollution -- nearly two billion tonnes a year, until recently.

But humans have also spent the past half-century tearing down and burning whole swathes of the Amazon to make way for cattle ranches and farmland.

Gatti, who works at Brazil's national space agency, has been tracking how much carbon the region emits and absorbs, watching for signs of a looming nightmare: that the destruction could push the Amazon to a "tipping point" where much of the rainforest dries up and turns to savannah.

When not in her lab outside Sao Paulo, Gatti can be found training bush pilots to collect her samples, by diving in a downward spiral from 14,500 feet, sucking up little flasks of air.

Gatti's is one of several recent studies to sound a blaring alarm on the Amazon.

It is based on data from 2010 to 2018.