Amazon Faces Historic Drought and Heat in 2023: What’s Driving the Crisis?

Redacción HC
07/04/2024

In 2023, the Amazon basin experienced a dual environmental catastrophe: the most severe drought in recorded history paired with scorching temperatures. The Rio Negro in Manaus dropped to an unprecedented 12.7 meters — the lowest since measurements began in 1902. October brought alarming temperature anomalies, peaking at +3°C above the 1981–2020 average, signaling a climatic emergency with profound implications for ecosystems, indigenous communities, and regional water security.

A recent study published in Scientific Reports by Espinoza et al. (2024) investigates the complex climatic interactions behind this crisis. By analyzing over a century of hydrological and atmospheric data, the researchers reveal a convergence of regional and global phenomena, including the rare back-to-back influence of La Niña and El Niño events, worsened by long-term ocean warming and possibly accelerated by deforestation.

How Did the Crisis Unfold?

From November 2022 to early 2023, the Amazon was still under the lingering effects of La Niña. This phenomenon, characterized by cooler Pacific Ocean surface temperatures, drove descending atmospheric flows and reduced rainfall in southwestern Amazonia. By mid-2023, the climate pendulum had swung dramatically in the opposite direction: El Niño conditions — marked by warm Pacific waters — intensified descending air circulation in the northern Amazon, suppressing rainfall even further.

These combined events created a "climate pincer effect" over the region. The study notes that “the atmospheric mechanisms reached record-breaking intensity,” exceeding even the extreme 2015–16 drought. Both the vertical integrated moisture flux (VIMF) and the anomalous descending airflows surpassed historical norms, confirming that 2023 was an outlier not only in its impact but also in its climatic origins.

Ocean Temperatures and Global Warming: A Perfect Storm

The researchers stress the importance of ocean surface temperatures (SSTs) in shaping Amazonian weather. While La Niña suppressed rainfall in early 2023, the rapid transition to El Niño in mid-year was unusual and aggressive. The global oceanic heat content — already at record highs due to anthropogenic climate change — acted as a thermal amplifier.

This dual shock—regional atmospheric changes layered over global ocean warming—helped create the most intense drought–heat coupling observed in over a century. “2023 stands out not only for how early the dry season began,” the authors state, “but also for how sustained and widespread the warming was across the basin.”

Impacts on Ecosystems and Communities

Record River Lows and Fish Mortality

Manaus’ river gauge readings confirmed the lowest water levels in 120 years. In many parts of the Amazon, dried-out riverbeds stranded boats and isolated communities. Fish die-offs became widespread as oxygen levels dropped in overheated, stagnant waters. A recent report by Braz-Mota & Val (2024) links these conditions to mass fish mortality, highlighting the biological cost of hydrological disruption.

Extreme Heat and Human Vulnerability

Temperatures in Manaus soared to 39.3°C in October, breaking the previous 2015 record. In riverine villages, heat combined with water scarcity to create a public health emergency — increasing risks of dehydration, food insecurity, and disease outbreaks.

Fire and Forest Degradation

With soils desiccated and humidity levels crashing, fire outbreaks surged. Though the study focuses on climatic drivers, the authors point to deforestation as a potential force multiplier. As forests are cleared, local rainfall-generating cycles weaken, reducing the ecosystem’s resilience to climate anomalies.

What Can Be Done?

The findings underscore the need for immediate policy and scientific responses.

1. Early Warning Systems: Real-time monitoring of ocean-atmosphere interactions can anticipate future drought risks. Incorporating La Niña–El Niño transitions into regional forecasting models will be critical.
2. Deforestation Control: Slowing deforestation is not just a biodiversity goal — it is essential for climate stability. Forests recycle water, maintain local humidity, and buffer temperature extremes.
3. Hydroclimatic Research Integration: The authors urge the development of integrated monitoring platforms that combine river flows, ocean temperatures, and land-use change data to forecast risk more accurately.
4. Community Preparedness: Local governments need contingency plans that include clean water access, food distribution, and health services during extreme events. Vulnerable communities cannot wait for annual disasters to act.

The Bigger Picture: Amazonia as Climate Thermostat

The Amazon rainforest plays a vital role in regulating South America's climate and even global weather patterns. Events like the 2023 drought not only devastate ecosystems locally but ripple outward, affecting precipitation cycles from the Andes to the southeastern coasts.

As extreme events become more common, understanding the interplay between global warming, ocean cycles, and land-use change is no longer a scientific luxury — it is a survival imperative.

Topics of interest

Climate Biodiversity