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The Amazon’s Water Transport Giants Set Global Records
The Amazon River demonstrates its enormous scale by discharging about 215,000–230,000 cubic meters per second of water, representing roughly 20% of all global riverine discharge into oceans. This massive water transport system accounts for approximately one-fifth of the total water carried to the oceans by rivers worldwide. The Amazon basin receives roughly 2000 mm of precipitation annually and contributes about 17% of global river freshwater input to the oceans. The sheer concentration is remarkable – approximately 13% of global precipitation over continental areas falls within the Amazon basin, which only covers 4.6% of the world’s land area.
Historic Water Level Extremes Tell Climate Stories
On October 26th, 2023, water levels at the port of Manaus plummeted to their lowest record since 1902, reaching 13.59 meters, with the descending water level amplitude hitting 15.6 meters – the highest on record, exceeding the long-term average by a staggering 50%. The Rio Negro reached its lowest levels since records began in 1902, dropping to 12.7 meters on the gauge at Manaus by October 27. These river levels represent the lowest in 120 years, threatening the estimated 30 million people living in the Amazon basin across several nations including Brazil, Peru, Colombia, Venezuela, Ecuador and Bolivia. The Madeira river, a major tributary, dropped to just 48 centimeters in Porto Velho on September 17th – a dramatic decrease compared to its normal level of 332 centimeters.
Flying Rivers Transport Water Beyond Borders
Flying rivers are massive areas of water vapour generated by the rainforest that flow across the Amazon basin, with the 400 billion trees estimated to be in the Amazon releasing 20 billion tonnes of water into the air every day. Transpiration creates this massive flow of vapor into the atmosphere, functioning like an irrigation system upside down. These aerial rivers of moisture from the Amazon contribute 16% of the rainfall in the La Plata River Basin, which extends for more than 2000 kilometers from the southern edge of the Amazon Basin to Buenos Aires, Argentina. Eastern trade winds from the Atlantic Ocean account for about half of Amazon rainfall, with the other half coming from evapotranspiration within the Amazon River Basin itself.
Critical Energy Infrastructure Depends on River Flows
The Amazon’s riverine system powers significant portions of affected countries’ energy through hydropower, with Brazil relying on hydropower for approximately 65-70% of its electricity, Colombia about 68-70%, Venezuela around 62-65%, Ecuador and Peru 55%, and Bolivia 32%. The recent drought significantly impacted dam capacities and energy output, leading to power cuts in the region as early as June 2023. Low water levels in the Amazon’s tributaries have halted hydroelectric production at Brazil’s fourth-largest dam, isolated hundreds of communities who depend on rivers for transportation, and led to mass mortality among river dolphins and fish. More than 60 municipalities declared a state of emergency under the drought conditions.
Unprecedented Temperature Anomalies Break Records
In October 2023, monthly maximum and minimum temperature anomalies in the Amazon region surpassed previous record values registered in 2015, reaching 3°C above normal considering the 1981-2020 average. Heat blanketed 60% of the rainforest, with temperatures running 2°C to 5°C above normal highs. Temperatures in 2023 and 2024 were exceptionally hot throughout the entire basin. While temperatures from 1985 to 1996 were consistently cooler than expected, temperatures from 2009 to the present have been considerably warmer.
Severe Seasonal Variations Intensify Weather Patterns
An amplified seasonal cycle of Amazonia precipitation during 1979-2018 has led to enhanced seasonalities in both Amazon river discharge and ocean salinity. During the dry season, the width of the Amazon River can be 4 to 5 kilometers in places, but in the wet season this can increase to 50 kilometers. Computer modeling suggests annual maximum flows will increase up to 50% in the Amazon River’s headwaters in the Andes, while annual minimum flows will decline by 20% to 50% throughout most of the region. A wet-season map shows most of the Amazon’s tributaries will discharge 20% to 50% more water by the end of the century.
Climate Change Multiplies Drought Probability
A modeling experiment by World Weather Attribution found that climate change has multiplied the likelihood of precipitation as low as that seen in the Amazon Basin in 2023 by a factor of 10, with the likelihood of an agricultural drought increased by a factor of 30. A recent study concluded that global climate change is the main driver of recent drying in the Amazon, with the World Weather Attribution Project estimating that the likelihood of drought has increased by a factor of 10-30 due to increasing temperatures and climate change. Since mid-2023, the Amazon River Basin has been in a state of exceptional drought, driven by low rainfall and consistently high temperatures for the entire year 2023.
Ocean Temperature Patterns Drive Amazon Rainfall
The immediate causes of Amazon climate variations lie thousands of kilometers away, in pools of anomalously warm water in the Pacific and Atlantic oceans, with El Niño creating low pressure zones that steer moist air away from the Amazon. Global sea surface temperatures have been rising steadily for more than a century, but in 2023 the global average broke previous records every month beginning in April. The Amazon’s worst droughts and most devastating fire seasons are usually linked to El Niño, with both of the two previous record-low streamflows in Rio Negro occurring during strong El Niño events in 1963 and 2010. One driver is an anomalous warm ocean current linked to climate change that carries heat from the Indian Ocean around the Cape of Good Hope into the South Atlantic.
Deforestation Creates Dangerous Feedback Loops
A significant amount of Amazonian land was deforested in 2022, totalling approximately 4.47 million acres, while in 2024 an area equivalent to the size of Italy burned in Brazil. Deforestation reduces regional rainfall in the Amazon and exacerbates the severity of droughts, creating a feedback loop between drought and deforestation that implies increases in either will impede efforts to curb both. Land conversion and deforestation in the Amazon currently release up to 0.5 billion metric tons of carbon per year, not including emissions from forest fires. Human actions and climate change are causing more rains and floods in the Amazon’s northern region and more severe droughts in the south.
Regional Distribution Changes Threaten Water Security
Scientists warn that changes will affect the flow of the Amazon River itself, with the new IPCC report warning that by the end of the century, global warming will reduce the flow of water in the Tapajós basin by one third and in the Araguaia-Tocantins basin by half. Global climate change and more deforestation will likely lead to increased temperatures and changing rain patterns in the Amazon, affecting the region’s forests, water availability, biodiversity, agriculture, and human health. Studies suggest that Amazon deforestation could potentially strengthen patterns of extreme drought in places as far away as California, while recent droughts in Texas and New Mexico might be linked to tree cutting in the Amazon. These aerial flows are now in peril, which could shrink rivers, parch crops, and hamper power plants on which millions of people depend.
Atmospheric Mechanisms Drive Extreme Weather
The historical dry and warm situation in Amazonia in 2023 is associated with two main atmospheric mechanisms: a strong southern anomaly of vertical integrated moisture flux over southwestern Amazonia during November 2022-February 2023, and downward motion over northern Amazonia from June-August 2023. Enhanced seasonal cycles are associated with similar amplifications in atmospheric vertical and horizontal moisture advections. Rainfall occurs in the Amazon from weather patterns that travel from the Atlantic Ocean westward across the Amazon lowlands toward the Andes mountains, where clouds converge and condense into rain as they hit the mountains. During El Niño, downward branches of circulation position over northern South America disrupt normal convection and rainfall over the Amazon.
Tipping Point Warnings Emerge From Research
The Amazon rainforest is moving toward a “tipping point,” especially in regions undergoing intense forest degradation and deforestation, characterized by a warming trend, lengthening dry seasons, and declining carbon sink capacity. Research shows that a warmer and drier environment could convert from 30% up to 60% of the Amazon rainforest into dry savanna, and if warming exceeds a few degrees Celsius, the process of savannisation may become irreversible. Experts warn that the Amazon may be approaching its point of no return, as deforestation and forest degradation have already affected around 13% of the biome. Over one third of the Amazon is struggling to recover from four supposedly “one-in-a-century” dry spells in less than 20 years, and the rainforest is in danger of “critical slowing down”.
Global Climate Engine Under Unprecedented Stress
The Amazon’s hydrological engine plays a major role in maintaining global and regional climate, with water released by plants through evapotranspiration and rivers influencing world climate and ocean current circulation. The Amazon River Basin stores up to five times the world’s annual greenhouse gas emissions each year. Up to 200 billion tonnes of carbon are stored in the Amazon’s forests and soils, essential in the global fight against climate change, and it is home to 10% of all species on Earth. The Amazon is reeling from two consecutive years of severe drought, with major rivers at record lows, leading to water shortages and transportation disruptions for local communities.
The Amazon basin’s rivers operate as Earth’s most powerful water distribution system, but they’re showing severe strain under climate pressure. These waterways don’t just drain South America – they help regulate rainfall patterns across entire continents and power the economies of multiple nations through hydroelectric generation. The current crisis reveals how quickly this massive system can shift from abundance to scarcity, with consequences rippling far beyond the rainforest’s borders.
