BRASILIA (REUTERS) - An area the size of Israel was deforested in the Amazon biome last year as destruction surged 21 per cent in the region spanning nine countries that is home to the world's largest rainforest, according to the Amazon Conservation organisation.

At that accelerated rate, the Amazon rainforest will reach a tipping point in 10 to 20 years, after which it will enter a sustained death spiral as it dries out and turns into a savanna, said Carlos Nobre, an earth systems scientist at University of Sao Paulo.

About 17 per cent to 18 per cent of the biome has already been destroyed, and with 1 per cent more cleared every three years, the tipping point of 20 per cent to 25 per cent destruction is rapidly approaching, said Nobre, who is not affiliated with the Amazon Conservation organisation.

"It is mandatory to reach zero deforestation in all of the Amazon in less than five years," Nobre said.

Amazon Conservation's first look at deforestation in the full year of 2020 shows that roughly 21,000 square kilometres of old-growth forest was cut or burned down, about the size of New Jersey, the US-based non-profit group found in its analysis of satellite data.

"These numbers are just mind-blowing," said Matt Finer, who leads the organisation's Amazon monitoring project.

The Amazon biome is overwhelmingly dominated by rainforest but includes other ecosystems that share a similar set of plants and animals. Many parts of the Amazon experienced drier weather last year and were therefore more susceptible to fire.

Bolivia accounted for the biggest increase in destruction compared to 2019 as enormous fires tore through its Chiquitano dry forests, Finer said. Many Bolivians use slash-and-burn tactics to clear land for cattle or soy, and the fires can get out of control and escape into the forest in dry conditions.

Bolivia announced a state of emergency in October, saying that 600 families had been affected by the fires.

After Bolivia, Peru, Colombia and Ecuador saw smaller increases in deforestation.

Brazil had the most deforestation, accounting for 61 per cent of the hotspots in the Amazon overall, although 2020 forest destruction was similar to 2019, Finer said.

"I think 2019 is regarded as a really bad year for the Brazilian Amazon. 2020 got less press and attention but it was just as bad, if not worse," he said.

The 2020 data is based on a preliminary analysis of deforestation alerts generated by the University of Maryland, with final figures to be confirmed later this year.