UPSC Prelims 2024 Q16: World's Largest Tropical Peatland — Explained
One of the following regions has the world's largest tropical peatland, which holds about three years worth of global carbon emissions from fossil fuels; and the possible destruction of which can exert detrimental effect on the global climate. Which one of the following denotes that region?
- Amazon Basin
- Congo Basin
- Kikori Basin
- Rio de la Plata Basin
Answer: (b) Congo Basin
Statement-wise explanation
- a: incorrect — The Amazon has the world's largest tropical rainforest, but not its largest tropical peatland. Its biggest peat area is in the Pastaza-Marañón foreland basin in Peru. A 2022 Nature Geoscience study put all of Peru's lowland peat at about 62,700 sq km and about 5.4 billion tonnes of carbon. That is roughly a fifth of the carbon in the central Congo peatland.
- b: correct — The Cuvette Centrale peatland lies in the central Congo Basin, shared by the Republic of Congo and the Democratic Republic of Congo. A 2022 Nature Geoscience study mapped it at about 16.7 million hectares (about 167,600 sq km). It stores about 29 billion tonnes of carbon (range 26–32 billion tonnes), which the study called 'roughly equivalent to three years' worth of global fossil fuel emissions'. It holds about 36% of the world's tropical peatland area and about 28% of tropical peat carbon.
- c: incorrect — The Kikori is a river in Papua New Guinea that flows into the Gulf of Papua. It runs through limestone country around Lake Kutubu. New Guinea has some peat swamps, but the Kikori basin is a small catchment. It is nowhere near the largest tropical peatland.
- d: incorrect — The Río de la Plata is the estuary of the Paraná and Uruguay rivers, between Argentina and Uruguay. Its basin is mostly subtropical and temperate, including the Pampas grasslands. It is not a tropical peatland region.
How to eliminate
Two options fall away with basic geography. The Río de la Plata basin lies largely outside the tropics, in Pampas and subtropical country, so it cannot hold the world's largest tropical peatland. The Kikori basin in Papua New Guinea is a small river catchment, so it is unlikely to store three years of global fossil fuel emissions. That leaves the Amazon and the Congo. Here the trap is to assume 'largest rainforest means largest peatland'. Option logic will not settle it. You have to know the fact: the world's largest tropical peatland is the Cuvette Centrale in the central Congo Basin. Scientists mapped it in 2017 and remapped it in 2022, and it holds about 29 billion tonnes of carbon.
Know more
Peatlands are wetlands where waterlogged, oxygen-poor conditions stop dead plant matter from fully decomposing. It builds up as peat, often over thousands of years. According to UNEP's Global Peatlands Initiative, peatlands cover only about 3% of the world's land, yet they store more carbon than all the world's forests combined. Draining, burning or clearing them releases this carbon as CO₂.
The Cuvette Centrale (central Congo Basin)
- It lies in a shallow, swampy depression of the Congo River system, shared by the Republic of Congo and the DRC.
- Scientists first mapped it in 2017 (Nature) and remapped it in 2022 (Nature Geoscience): about 167,600 sq km, roughly the size of England and Wales combined.
- Recent dating suggests the peat began forming about 42,000 years ago.
- Only about 8% of it lies in national protected areas. About a quarter of its carbon sits in areas allocated for logging, mining or palm oil, and oil blocks have been offered over parts of it.
- The Brazzaville Declaration (March 2018) was signed by the Republic of Congo, the DRC and Indonesia under UNEP's Global Peatlands Initiative to protect it.
| Tropical peat region | Area | Carbon stored |
|---|---|---|
| Central Congo Basin (Cuvette Centrale) | ~167,600 sq km | ~29 billion t |
| Peruvian Amazon (incl. Pastaza-Marañón) | ~62,700 sq km | ~5.4 billion t |
| Indonesia / SE Asia | Large, heavily drained | Major source of fire emissions |
Why it matters for climate: a drained peatland stops being a carbon sink and becomes a source. That is why peatland loss is discussed alongside climate tipping points. In India, MoEFCC has started a peatland inventory and assessment under its wetlands programme.
In the news
In July 2022 a Nature Geoscience study remapped the central Congo peatland. It found about 29 billion tonnes of carbon, 'roughly equivalent to three years' worth of global fossil fuel emissions', which is almost exactly the question's wording. In the same year the DRC put oil blocks overlapping the peatland up for auction, and that drew worldwide coverage.
NCERT Concepts to Revise
- Congo Basin rainforest: One option is the Congo Basin; knowing its equatorial, swampy rainforest setting helps you judge where large tropical peat can form.
- Congo River: The Congo River system drains the central basin depression, so its course shows where the region in the question sits.
- Amazon rainforest: The Amazon is the most tempting option because it is the largest tropical rainforest; separate 'largest rainforest' from 'largest peatland'.
- Pampas: The Pampas lie in the Río de la Plata region; knowing they are temperate grasslands tests whether that basin is tropical at all.
- Climate tipping points: The question warns that destroying the peatland could harm the global climate; tipping points explain how such carbon losses can become self-reinforcing.