Deforestation triggering irreversible transition in Amazon hydrological cycle

Abstract

The Amazon is hypothesized to reach an irreversible “tipping point” when deforestation slows the hydrological cycle sufficiently that tropical forest ecosystems cannot be sustained. However, inception of such a tipping point has not been supported by observations and the relevant links between deforestation and atmospheric moisture recycling are poorly understood. Here we show that reduction in evapotranspiration from 20 years of deforestation dried the atmosphere persistently and caused moisture decoupling, i.e., an opposite sign of moisture change between the lower and middle troposphere. Increased deforestation exacerbated the lower troposphere drying and caused it to penetrate deeper into the middle troposphere in the dry and transition seasons over monsoon forests and savannas. Deforestation induced warming-enhanced buoyant updrafts, elevated hot and dry air and thereby reduced downward mixing of water supplies from the tropical Atlantic that normally moisten the Amazon forests. The severe atmospheric desiccation in the southern and eastern Amazon cannot be compensated by enhanced water supplies from the Atlantic Ocean, demonstrating an irreversible transition in Amazon hydrological cycle exacerbated by rapid deforestation. The more recent drying through the seasons over rainforests and during the wet season over the transition zones from rainforests to monsoon forests and savannas, however, suggests a window of opportunity for preventing ecosystem collapse with forest conservation.

Ten new insights in climate science 2022

“…Driven by climate change and deforestation as combined indirect and direct drivers, ecosystem productivity in tropical rainforests has declined and part of the Amazon region has become a net source of carbon (Gatti et al, 2021). Localized fire feedbacks and changing precipitation patterns amplify drought intensity as well as forest and carbon loss (Xu et al, 2022), which increases vegetation-climate feedbacks and decreases resource availability for the livelihoods of local communities (Nobre et al, 2021).…”

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“…This region covers an area of approximately 5,200,000 km 2 and represents over 59% of Brazil's land mass [3]. Therefore, the increase in the deforestation rates could lead to irreversible alterations in this tropical region, such as the greenhouse effect, soil erosion, and climate change [1,[4][5][6][7].…”

The Organic Synthesis of a Dimeric Lignin Probe Utilizing Förster Resonance Energy Transfer (FRET)

“…12 For instance, 20 years of deforestation in the Amazon rainforest has significantly reduced the flow of evapotranspiration, which is integral in a third of the precipitation of the Amazon. 50 The Amazon is reaching an irreversible climax as the hydrological cycle is reduced to the point where the ecosystems within the rainforest will not be able to sustain life. 50 The reduced recycling of evapotranspiration for precipitation has placed water stress on forests, making them more prone to fires.…”

“…50 The Amazon is reaching an irreversible climax as the hydrological cycle is reduced to the point where the ecosystems within the rainforest will not be able to sustain life. 50 The reduced recycling of evapotranspiration for precipitation has placed water stress on forests, making them more prone to fires. 50 Additionally, vector-borne diseases mutate as global temperatures get higher, extending transmission, and increasing the level of contagiousness.…”

“…50 The reduced recycling of evapotranspiration for precipitation has placed water stress on forests, making them more prone to fires. 50 Additionally, vector-borne diseases mutate as global temperatures get higher, extending transmission, and increasing the level of contagiousness. 51 Global warming and climate change have led to an increase in epidemics and even played a hand in the current Covid-19 pandemic, where SARS-CoV-2 is constantly mutating, forming new strains.…”