The scientists, however, did not specify when Amazon rainforest's "tipping point" might be reached.
The Amazon rainforest is heading towards a tipping point beyond which much of it will be replaced by grassland, a new study has said. It has been carried out by University of Exeter, the Potsdam Institute for Climate Impact Research (PIK) and Technical University of Munich.
The study is based on satellite data from 1991 to 2016 and has been published in Nature.
In the research, the scientists have said that the Amazon rainforest is losing its ability to bounce back from damages caused by droughts and land-use changes. If the rainforest crosses a critical threshold, the scientists said, it will have vast consequences for biodiversity and climate change.
"We find that more than three-quarters of the Amazon rainforest has been losing resilience since the early 2000s, consistent with the approach to a critical transition. Resilience is being lost faster in regions with less rainfall and in parts of the rainforest that are closer to human activity," the scientists said in the study.
A vicious cycle of damage could trigger "dieback", the study further said.
The scientists, however, did not specify when the "tipping point" might be reached.
"The Amazon stores lots of carbon and all of that would be released into the atmosphere, which would then further contribute to increasing temperatures and have future effects on global mean temperatures," Dr Chris Boulton, one of the three authors of the study, told the BBC.
Another researcher, Dr Tim Lenton, said losing the rainforest could result in up to 90 billion tons of heat-trapping carbon dioxide getting put back into the atmosphere. Dr Lenton is director of the Global Systems Institute at the University of Exeter in England.
The Amazon rainforest covers two million square miles in Brazil and neighbouring countries and plays a crucial role in mitigating climate change by taking in more carbon dioxide from the atmosphere than it releases (acing as a large terrestrial carbon sink). It is also rich in diversity if plant and animal species.
In recent years, widespread deforestation and burning of agriculture has taken its toll on the rainforest. In January this year, deforestation in the Brazilian Amazon set a new record.
Nearly 360 square kilometres (140 square miles) of forest cover - an area more than six times the size of Manhattan - were destroyed in the Brazilian Amazon from January 1 to January 21, according to Brazil's national space research institute, INPE.