Human activity and drought ‘degrading more than a third of Amazon rainforest’ | Amazon rainforest
Human activity and drought may have led to the degradation of more than a third of the Amazon rainforest, more than double the previous estimate, according to a study that heightens fears that a globally important ecosystem is slipping towards a point of no return.
Fires, land conversion, deforestation and water shortages have weakened resilience to 2.5 million square meters. km of forest, the area of which is 10 times the size of the UK. This area is now drier, more flammable and more vulnerable than before, prompting the authors to warn of “megafires” in the future.
Between 5.5% and 38% of what is left of the world’s largest rainforest is also less able to regulate climate, generate rainfall, store carbon, provide habitat for other species, provide livelihoods for local populations, and sustain itself as a sustainable ecosystem, the paper notes.
This degradation exceeds the 17% of the original forests, which were completely cut down in the last half century as Brazil pushed back its agricultural and mining frontiers to meet the needs of an increasingly wealthy, more populous and consuming world.
Brazil’s new president, Luiz Inácio Lula da Silva, has vowed to change the direction of zero deforestation policy. But the authors say degradation must also be worked on if we are to avoid future megafires.
“Now there is hope, but our newspaper shows that this is not enough to solve the problem of deforestation. There is still a lot of work to be done,” said Jos Barlow of Lancaster University.
The findings, published Thursday in the journal Science, are based on a review of existing research, recent satellite data and a new assessment of the impact of drought by an international team of 35 scientists and researchers from institutions such as Brazil’s University of Campinas (Unicamp). Institute for Environmental Studies of the Amazon (IPAM), National Institute for Space Research (INPE) and Lancaster University UK.
Water deprivation explains much of the increase in Amazon degradation from the previous estimate of 17%. Drought is a growing concern as it increases the vulnerability of forests to fires and reduces by 34% their ability to self-repair through evapotranspiration—the formation of rain clouds by trillions of plants.
This has indirect implications in the wider region, including food-producing areas that depend on the Amazon’s “flying rivers” to irrigate crops. Most worryingly, the specter of a destructive feedback loop is emerging in which drought makes the forest less able to pump water, leading to more drought.
To prevent these risks from spiraling out of control, the authors urge policymakers to reduce the drivers of degradation and treat it in the same way as the more well-known problem of deforestation. They differ greatly in appearance. Deforestation is the complete clearing of forests and the conversion of land for other uses that can be easily determined by satellites. Degradation, on the other hand, is the partial loss of vegetation due to human activities, which is often hidden as it occurs under the canopy of larger trees.
To the naked eye, the difference is as great as between completely shaved hair and thinned hair. But degradation has no less impact than local deforestation, since it affects a much larger area. The paper states that the amount of carbon released from degradation can be even higher than from deforestation.
The authors acknowledge significant uncertainty in their estimates as degradation is difficult to measure and define. This is reflected in a wide range of affected area estimates, from 5.5% remaining forest if only fires, logging and edge effects are taken into account, to 38% if drought effects are added.
The impact on society is unevenly distributed. Most of the economic benefits from logging and land clearing go to outlying cities and other countries. On the contrary, most of the negative impacts – loss of forest products, deterioration of air quality, deterioration of water quality – occur on indigenous and other forest communities.
Barlow warns of socio-economic tipping points, when the forest is so degraded that locals leave it, which means less protection from the mining industry.
The authors of the document advise policymakers to step up monitoring of degradation, strengthen fire fighting capacity, limit deforestation and create buffer zones of secondary forests to protect the open borders of the original vegetation.