Two new scientific review articles by international teams of researchers have painted a bleak picture of the state of the Amazon rainforest: The critical ecosystem is being damaged at an unprecedented pace, they warn, which may usher in "a qualitatively different global climate regime” with grievous effects on biodiversity and human welfare.

The papers, both published in the peer-reviewed journal Science on Thursday, summarize research on deforestation and landscape degradation in the Amazon to deliver a sharp message. The region that is key to the world’s climate system "is now perched to transition rapidly from a largely forested to a nonforested landscape,” write one set of authors, "and the changes are happening much too rapidly for Amazonian species, peoples, and ecosystems to respond adaptively.”

The main culprits are human activities, such as logging and clearing forest for cattle pasture, and climate change.