Topline
Over three-quarters of the Amazon rainforest has been losing its ability to recover from drought and man-made disruptions since the early 2000s, threatening to push the rainforest past a “tipping point” of mass plant death that could drastically affect the global carbon cycle, according to a study published Monday by Nature Climate Change.
An area of Brazil’s Amazon rainforest decimated by wildfires, as seen on August 25, 2019.
Key Facts
The study used satellite photo, radio and microwave data to measure variables like leaf greenness and plant stem thickness, reflecting how rapidly plants recovered from drought or human activity.
Large swathes of Amazon rainforest that appear healthy may be on the brink of mass dieback—when a plant starts to die beginning at the tips of its roots or leaves—due to deforestation and increasingly frequent droughts caused by climate change, researchers said.
The rainforest is losing its ability to recover from disruption fastest in areas that have low annual precipitation or are nearer to human encroachment, according to the study.
Increased drought could make the localized fires that have historically been a normal feature of the environment grow into “mega-fires” that could wipe out large areas of the rainforest “in a decade or two,” study co-author Tim Lenton told Bloomberg Green.
A 2000 Nature study projected mass plant dieback in the Amazon rainforest could occur as early as the late 21st century, though the study published Monday concluded this timeframe could vary according to greenhouse gas emission levels.
Key Background
In a 2021 Royal Meteorological Society (RMetS) study, Lenton and other researchers identified areas vulnerable to climate “tipping points,” in which a small degree of climate change can trigger an abrupt shift in the area’s climate system. According to the RMetS study, mass dieback in the Amazon rainforest could trigger one such climate tipping point. Historically, the Amazon has sucked billions of tons of carbon out of the air through photosynthesis, storing it in materials like wood. However, the Amazon’s ability to absorb carbon has declined over the past four decades, according to the Nature Climate Change study. Low rainfall can diminish forests’ resilience to disruption, possibly because water-stressed plants struggle to stay regulated, researchers said. In 2005 and 2010, the rainforest temporarily began to produce more carbon than it was absorbing, following mass tree death caused by unprecedented droughts. A combination of manmade climate change and deforestation has left the Amazon highly vulnerable to drought and other extreme climate events, leaving scientists uncertain how quickly it is approaching a climate tipping point that could cause wide-reaching changes to global climate systems.
Contra
There’s still a chance to stop inflicting damage to the Amazon rainforest, Niklas Boers, a co-author of the Nature Climate Change study, told Bloomberg Green. “We haven’t crossed that tipping point yet,” Boers said. “So there’s still hope.”
Tangent
Deforestation in the Brazilian Amazon has risen under President Jair Bolsonaro, who has reportedly undercut the abilities of environmental agencies. However, in April 2021, Bolsonaro publicly committed his country to achieve carbon neutrality by 2050, following pressure from the Biden Administration.
Further Reading
“Large Chunk Of Amazon Rainforest Now Emits More Carbon Than It Takes In, Study Finds” (Forbes)
Source: https://www.forbes.com/sites/zacharysmith/2022/03/07/large-swathes-of-amazon-rainforest-could-be-on-brink-of-die-off-study-says/