to threatening the livelihoods of millions of people.
This is the impact of the Amazon rainforest's historic drought.
Its sapped the Amazon River and four of its biggest tributaries to their lowest level in at least half a century.
And the worst may be yet to come.
Experts are predicting an even more intense drought next year - due to extreme ocean temperatures worsened by global warming.
(Rosimeire Araujo Silva, Scientist)
"What is expected is that next year there will still be a drought due to this year's low water levels, and that happens because the water reserve will be compromised, also because of this year's drought."
Amazonas, which has been hit hardest by the drought, declared a public emergency in September.
The state has delivered drinking water and food staples via aircraft and smaller boats.
Helicopters are working overtime to airlift the sick.
Meanwhile, thousands of students are enrolled in online classes because they can no longer get to school.
The federal government has pledged millions of dollars towards relief efforts.
SILVA: "The human side is the one that suffers these consequences the most."
Nine scientists interviewed by Reuters said the effects of the drought will only begin to recede with the onset of the rainy season in late 2024.
Five of those scientists didn't expect the Amazon to recover before 2026.
They expect it will take two healthy rainy seasons to restore normal soil moisture in the rainforest.
But even that could change, based on El Nino.
The naturally occurring phenomenon roils global weather every two to seven years.
As it warms waters off the Pacific coast of South America, it pulls rains in that direction... depressing precipitation in the Amazon.
The current El Nino is estimated to last until mid-2024.