Amazon Forests: Drought Intensifies the Shift from Carbon Sink to Carbon Source

Environment | Amazon, carbon sink, drought, GS-III | News reference: 21 October 2026 | Published: 5 November 2026

Main Findings of the Study

• Human impacts dominate: Deforestation, degradation through selective logging and fires, and edge effects are the main drivers of emissions. Counting clearing alone understates the overall damage.
• Drought acts as a multiplier: El Niño-related drought increases tree deaths and flammability, raising emissions and weakening carbon absorption.
• A cause for concern: If the Amazon crosses a tipping point towards savannisation, regional rainfall and the global carbon cycle could be seriously affected.

Connections with India and the Examination

• The credibility of REDD+ emission-reduction mechanisms and forest carbon finance depends on measuring degradation, not merely clearing.
• The climate feedback loop runs from drought to higher emissions, greater warming and further drought.
• Sink accounting matters in India's green-economy debate. Its NDC includes a target for an additional sink of 2.5-3 billion tonnes of CO2 equivalent.

Examination Relevance

Prelims: Amazon basin countries, Brazil's approximately 60% share, tipping points, REDD+, and the El Niño-rainfall relationship.

Mains, GS-3: Degradation versus deforestation, climate feedback, disputes over sink accounting in the COP process, and links between biodiversity and climate.

What Is the Study?

This study was published in open access in the journal Nature on 21 October 2026, titled "Amazon carbon emissions driven by human actions amplified by droughts". The lead author is Luciana Gatti. The researchers used 15 years of data derived from measurements of atmospheric CO₂. That is, the Amazon's carbon balance was worked out not by counting the forest directly, but from changes of carbon in the air.

Key Figures

Item	Finding (study)
15-year average carbon balance	0.32 ± 0.08 PgC per year (net emission)
Emissions from fires	0.40 ± 0.07 PgC per year, the largest source
Group 1: wet years, low human activity (2011-2014, 2017, 2018)	0.11 ± 0.08 PgC per year
Group 2: low climate stress, high human activity (2019-2022)	0.43 ± 0.13 PgC per year
Group 3: hot and dry years (2010, 2015, 2016, 2023, 2024)	0.49 ± 0.07 PgC per year
Year of highest emissions	2024: 0.81 ± 0.09 PgC

PgC means petagram of carbon; 1 PgC equals one billion tonnes of carbon. These are figures for carbon, not CO₂. The number is larger when converted to CO₂, so check the unit in the question.

What to Learn from the Three Groups

• Human activity alone also raises emissions: In the Group 2 years climate stress was low, yet emissions stayed high because of deforestation and degradation.
• Drought raises it further: In the Group 3 years (those with El Nino and warming of the tropical North Atlantic), emissions from fires and drought were highest.
• In wet years the Amazon stayed nearly neutral: In Group 1 the balance was close to 0.11 PgC. In the wet season of 2023 the study period's largest carbon sink was seen, and 2024 brought the highest emissions in the middle of El Nino.

Check the Terms

• Carbon sink: an area that absorbs carbon from the atmosphere. Carbon source: one that releases it. The study says that the forest's absorption cannot make up for rising emissions.
• Deforestation versus degradation: In deforestation the forest is removed; in degradation the trees remain standing but the carbon stock falls.
• El Nino: a warming event in the Pacific Ocean that increases drought in many places.

India's Carbon-Sink Target: Check the Unit

India's NDC target is to create an additional carbon sink of 2.5-3 billion tonnes of CO₂-equivalent through additional forest and tree cover by 2030. This is a stock target stated in CO₂-equivalent, unlike the study's annual carbon flow in PgC per year. The numbers cannot be compared directly.

Caution

This is a scientific study and its figures come with ranges of uncertainty (the ± figures). Do not read it as an official government account. In the exam, be careful with a statement like "the whole Amazon has permanently become an emitter"; the study speaks of the 15-year average net emission and says that in wet years the situation stays nearly neutral.

Additional Sources

1. Nature, 21 October 2026: Amazon carbon emissions driven by human actions amplified by droughts
2. MoEFCC: India's Long-Term Low-Carbon Development Strategy (NDC carbon-sink target)

Mains Practice Question

"The Amazon rainforest's movement from a carbon sink towards a carbon source is driven more by forest degradation and climate feedback than by deforestation alone." Examine this statement in light of the recent study and suggest its implications for India's forest conservation and climate goals. (250 words)

Answer Outline

Introduction:

Present the study's central finding: human activities cause emissions and drought intensifies their effects.

Main Body:

Distinguish degradation from deforestation. Discuss El Niño, rainfall, climate feedback and tipping-point risks. Include the COP debate on carbon-sink accounting. Explain implications for REDD+, India's forest-cover goals, and coordinated biodiversity and climate policy.

Conclusion:

Assess conservation through forest condition and carbon balance, rather than area alone.

Prelims Practice Questions

Sources

Nature, 21 October 2026, open access.

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