The Amazon rainforest covers an area of 5.5 million km2. It is also home to about 200,000 people. One in tenof all known species. At least 40,000 plants, 2,200 fish and 1,200 birds have been scientifically classified in the area. Nearly 2.5 million insect species have also been identified.
Since at least 55,000,000 years ago, the Amazon has been a lush rainforest that is alive with life. But the Amazon is now a vibrant, humid rainforest. A new paperScientists claim that climate change has caused 75% of the ecosystem to lose their resilience since 2000. This is most apparent in areas closer to human activity and in areas receiving less rain.
The resilience of an ecosystem – its capacity to maintain usual processes like the regrowth of vegetation following drought – is a notoriously difficult concept for scientists to measure. The authors analysed satellite images from remote areas of Amazon rainforest between 1991 and 2016. They used a measurement called vegetation optic depth to show that forest biomass (the total weight all organisms in an area) is taking longer for these areas to recover from stresses.
This, they argue, suggests that longer dry seasons and drier conditions caused by climate change are undermining the rainforest’s ability to recover from successive droughts. The authors note that drought-sensitive tree varieties are being replaced by drought resistant species at a slower pace than the rapid changes in regional climate.
Is this new research a credible warning sign? Here’s what the evidence tells us.
An ecosystem that is less resilient becomes less capable of recovering from stressors like droughts. This is known as “critical slowing down”.
If stress continues, it is more likely that the ecosystem will reach a place where it cannot be sustained. Changes abruptlyTo a new state. In other words, a critical slowing down could be an early warning sign of impending collapse.
The authors use satellite data for a better measurement. The water contentThe Amazon’s trees are more important than their biomass. The authors could be observing that the rainforest patches they studied are not losing trees. Instead, dry seasons increase and droughts proliferate. This is what scientists have observed in the Amazon. in recent decades.
However, research on rainforest plots reported elsewhere support the new study’s claim that biomass in the rainforest is taking longer to recover from stress. According to measurements taken, trees are dying faster and growing back slower which contributes to a decrease in total biomass in Amazon. The same period.
The new paper provides further evidence that Amazonian vegetation is changing. These changes may indicate that Amazon’s rainforest is losing resilience. Or that seasons are becoming more frequent with more droughts.
These results are not able to tell us when a crucial transition is likely to occur or if one is already in progress. Unanswered is the question of whether Amazon is at a tipping point that could turn it into another state.
This paper examined the effects of climate change on the rainforest, specifically the longer and drier droughts. However, scientists know that the stress-producing factors of road-building and expanding farmland can also be severe. The combined effects of these could lead to the Amazon’s collapse if the threshold above which it is vulnerable does not yet exist. It’s better to act sooner than laterIt is possible to expect a lot more from one stress if you look at it in isolation. It might take some time to transition once it has begun. Only a few yearsAmazon is now in a new state.
New research highlights the need to reverse global warming emissions, reduce pressure on the rainforests and preserve habitats to counter the effects of a dry climate. We may not be the last generation to have the privilege of sharing a planet. These ecosystems.
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