Previous Year Question

1. The peatland concerned

The world’s largest known tropical peatland is located in the Congo Basin of Central Africa. It is principally known as the Cuvette Centrale peatland complex.

It extends across two countries:

• Democratic Republic of the Congo—DRC

• Republic of the Congo

The peat occurs beneath the swamp forests and permanently waterlogged areas of the central Congo Basin.

2. What is peat?

Peat is an accumulation of partially decomposed vegetation and other organic material. Waterlogging creates oxygen-poor conditions in the soil, preventing dead vegetation from decomposing completely. Consequently, the carbon contained in this vegetation remains stored below the ground for thousands of years.

Peat accumulation in the Congo peatlands is believed to have begun approximately 10,600 years ago, during the early Holocene.

3. Area and carbon storage

According to the initial scientific assessment published in 2017:

• The peatland covered approximately 145,500 square kilometres.

• Its median peat depth was approximately 2 metres, while the maximum recorded depth was about 5.9 metres.

• It stored approximately 30.6 petagrams of carbon.

• One petagram equals one billion tonnes; therefore, this represents approximately 30.6 billion tonnes of carbon.

• This quantity has been considered equivalent to approximately three years of global carbon emissions from fossil fuels.

Later and more extensive mapping has estimated its area at approximately 168,000 square kilometres. The variation between estimates results from improvements in surveying and mapping methods.

4. Why would its destruction threaten the climate?

As long as the peatland remains naturally waterlogged, most of its carbon stays locked below the ground. However, the following activities can turn it into a source of carbon emissions:

• Drainage for agriculture or plantations

• Deforestation

• Oil, gas or mineral exploitation

• Construction of roads and other infrastructure

• Drought and rising temperatures

• Peat fires

After drainage, peat becomes exposed to oxygen and begins decomposing rapidly. This can release large quantities of carbon dioxide into the atmosphere. Dried peat can also burn for prolonged periods, producing additional greenhouse-gas emissions. Its destruction can, therefore, accelerate global warming.

5. Why are the other options incorrect?

• Amazon Basin: It is the world’s largest river basin and contains the most extensive tropical rainforest, but the largest tropical peatland complex referred to in the question is situated in the Congo Basin.

• Kikori Basin: It is a river basin in Papua New Guinea. It contains wetlands and peat areas, but it is not the vast peatland described in the question.

• Rio de la Plata Basin: It is a major South American drainage basin comprising rivers such as the Paraná, Paraguay and Uruguay; it is unrelated to the Cuvette Centrale peatland.

Fact: The Congo Basin contains the world’s second-largest contiguous tropical rainforest after the Amazon, while the Cuvette Centrale beneath its swamp forests is the world’s largest known tropical peatland complex.