Amazon’s ‘tipping point’ may vary within the forest

Large areas of tropical forests in South America could reach a tipping point later this century and undergo a process of “savannization,” according to a new study by Brazilian and American researchers recently published in scientific journal PNAS.

Around 4 million square kilometers that have undergone long periods of waterlogging, such as hills and valleys of the rivers Amazon, Puru, and Madeira in the northwest of the Amazon region, may be at some level of risk of transforming into savanna. Most of the at-risk areas are in the Amazon, but also in other parts of tropical biomes, such as Peruvian rainforests — which hold important carbon stocks.

“It’s not a savanna like the Cerrado, that is rich and biodiverse. It’s a degraded state with little biodiversity and carbon stocks,” says Caio Mattos, a researcher at Princeton University and the National Oceanic and Atmospheric Administration (NOAA), in the U.S., to The Brazilian Report.

Researchers used 15 years of data on rainfall, topography, soil type, and relief to build a mathematical model that represents the monthly depth of the water table in tropical areas in Latin America.

According to the study, climate change should cause a situation of double stress between the wet and the dry seasons in floodplains. The increase in seasonality and the decrease in rainfall in the coming...