Cuvette Centrale

Last updated

The Cuvette Centrale (French: "Central Basin") is a region of forests and wetlands in the Democratic Republic of the Congo. Some definitions consider the region to extend into the Republic of the Congo as well. [1] It lies in the center of the Congo Basin, bounded on the west, north and east by the arc of the Congo River.

Contents

Description

A lake covered the region during the Pliocene epoch, which was gradually filled with sediments, and the surface of the basin is very flat. Slow-moving tributaries of the Congo, including the Lopori, Maringa, Ikelemba, Tshuapa, Lomela and Lokoro, drain westward.

The region lies on the equator, where the climate is tropical and humid. Rainfall averages 2,000 mm annually.

The Eastern Congolian swamp forests extend along the Congo River and its chief tributaries, and cover wide areas in the western portion of the Cuvette Centrale. These swamp forests are seasonally or permanently flooded. The Central Congolian lowland forests extend across the remaining portion of the region. The swamp forests are home to endangered species of megafauna, including lowland gorillas and forest elephants. [1]

Climate change

Map of Cuvette Centrale location in the Congo Basin. Three graphs portray the evolution of its peatland carbon content over the past 20,000 years, as reconstructed from three peat cores. Garcin 2022 Cuvette Centrale.jpg
Map of Cuvette Centrale location in the Congo Basin. Three graphs portray the evolution of its peatland carbon content over the past 20,000 years, as reconstructed from three peat cores.

In 2017, it was discovered that 40% of the Cuvette Centrale wetlands are underlain with a dense layer of peat, which contains around 30 petagrams (billions of tons) of carbon. This amounts to 28% of all tropical peat carbon, equivalent to the carbon contained in all the forests of the Congo Basin. In other words, while this peatland only covers 4% of the Congo Basin area, its carbon content is equal to that of all trees in the other 96%. [1] [2] [3] It was then estimated that if all of that peat burned, the atmosphere would absorb the equivalent of 20 years of current United States carbon dioxide emissions, or three years of all anthropogenic CO2 emissions. [2] [4]

This threat prompted the signing of Brazzaville Declaration in March 2018: an agreement between Democratic Republic of Congo, the Republic of Congo and Indonesia (a country with longer experience of managing its own tropical peatlands) aiming to promote better management and conservation of this region. [5] However, 2022 research by the same team which had originally discovered this peatland not only revised its area (from the original estimate of 145,500 square kilometres (56,200 sq mi) to 167,600 square kilometres (64,700 sq mi)) and depth (from 2 m (6.6 ft) to (1.7 m (5.6 ft)) but also noted that only 8% of this peat carbon is currently covered by the existing protected areas. For comparison, 26% of its peat is located in areas open to logging, mining or palm oil plantations, and nearly all of this area is open for fossil fuel exploration. [6]

Even in the absence of local disturbance from these activities, this area is the most vulnerable store of tropical peat carbon in the world, as its climate is already much drier than that of the other tropical peatlands in the Southeast Asia and the Amazon Rainforest. A 2022 study suggests that the geologically recent conditions between 7,500 years ago and 2,000 years ago were already dry enough to cause substantial peat release from this area, and that these conditions are likely to recur in the near future under continued climate change. In this case, Cuvette Centrale would act as one of the tipping points in the climate system at some yet unknown time. [3] [7]

Related Research Articles

<span class="mw-page-title-main">Swamp</span> A forested wetland

A swamp is a forested wetland. Swamps are considered to be transition zones because both land and water play a role in creating this environment. Swamps vary in size and are located all around the world. The water of a swamp may be fresh water, brackish water, or seawater. Freshwater swamps form along large rivers or lakes where they are critically dependent upon rainwater and seasonal flooding to maintain natural water level fluctuations. Saltwater swamps are found along tropical and subtropical coastlines. Some swamps have hammocks, or dry-land protrusions, covered by aquatic vegetation, or vegetation that tolerates periodic inundation or soil saturation. The two main types of swamp are "true" or swamp forests and "transitional" or shrub swamps. In the boreal regions of Canada, the word swamp is colloquially used for what is more formally termed a bog, fen, or muskeg. Some of the world's largest swamps are found along major rivers such as the Amazon, the Mississippi, and the Congo.

<span class="mw-page-title-main">Peat</span> Accumulation of partially decayed vegetation

Peat is an accumulation of partially decayed vegetation or organic matter. It is unique to natural areas called peatlands, bogs, mires, moors, or muskegs. Sphagnum moss, also called peat moss, is one of the most common components in peat, although many other plants can contribute. The biological features of sphagnum mosses act to create a habitat aiding peat formation, a phenomenon termed 'habitat manipulation'. Soils consisting primarily of peat are known as histosols. Peat forms in wetland conditions, where flooding or stagnant water obstructs the flow of oxygen from the atmosphere, slowing the rate of decomposition. Peat properties such as organic matter content and saturated hydraulic conductivity can exhibit high spatial heterogeneity.

The Global 200 is the list of ecoregions identified by the World Wide Fund for Nature (WWF), the global conservation organization, as priorities for conservation. According to WWF, an ecoregion is defined as a "relatively large unit of land or water containing a characteristic set of natural communities that share a large majority of their species dynamics, and environmental conditions". For example, based on their levels of endemism, Madagascar gets multiple listings, ancient Lake Baikal gets one, and the North American Great Lakes get none.

<span class="mw-page-title-main">Congo Basin</span> Sedimentary basin of the Congo River in Central Africa

The Congo Basin is the sedimentary basin of the Congo River. The Congo Basin is located in Central Africa, in a region known as west equatorial Africa. The Congo Basin region is sometimes known simply as the Congo. It contains some of the largest tropical rainforests in the world and is an important source of water used in agriculture and energy generation.

<span class="mw-page-title-main">Peat swamp forest</span> Tropical moist forests where waterlogged soil prevents dead leaves and wood from fully decomposing

Peat swamp forests are tropical moist forests where waterlogged soil prevents dead leaves and wood from fully decomposing. Over time, this creates a thick layer of acidic peat. Large areas of these forests are being logged at high rates.

<span class="mw-page-title-main">Congolian rainforests</span> Broad belt of rainforest in Central Africa

The Congolian rainforests are a broad belt of lowland tropical moist broadleaf forests which extend across the basin of the Congo River and its tributaries in Central Africa.

<span class="mw-page-title-main">Freshwater swamp forest</span> Forest growing on an alluvial zone

Freshwater swamp forests, or flooded forests, are forests which are inundated with freshwater, either permanently or seasonally. They normally occur along the lower reaches of rivers and around freshwater lakes. Freshwater swamp forests are found in a range of climate zones, from boreal through temperate and subtropical to tropical.

<span class="mw-page-title-main">Borneo peat swamp forests</span> Ecoregion in Borneo

The Borneo peat swamp forests ecoregion, within the tropical and subtropical moist broadleaf forests biome, are on the island of Borneo, which is divided between Brunei, Indonesia and Malaysia.

<span class="mw-page-title-main">Tropical peat</span>

Tropical peat is a type of histosol that is found in tropical latitudes, including South East Asia, Africa, and Central and South America. Tropical peat mostly consists of dead organic matter from trees instead of spaghnum which are commonly found in temperate peat. This soils usually contain high organic matter content, exceeding 75% with dry low bulk density around 0.2 mg/m3 (0.0 gr/cu ft).

<span class="mw-page-title-main">Tipping points in the climate system</span> Large and possibly irreversible changes in the climate system

In climate science, a tipping point is a critical threshold that, when crossed, leads to large, accelerating and often irreversible changes in the climate system. If tipping points are crossed, they are likely to have severe impacts on human society and may accelerate global warming.

<span class="mw-page-title-main">Central Congolian lowland forests</span>

The Central Congolian lowland forests are an ecoregion within the Democratic Republic of the Congo. This is a remote, inaccessible area of low-lying dense wet forest, undergrowth and swamp in the Cuvette Centrale region of the Congo Basin south of the arc of the River Congo.

<span class="mw-page-title-main">Peatland</span> Wetland terrain without forest cover, dominated by living, peat-forming plants

A peatland is a type of wetland whose soils consist of organic matter from decaying plants, forming layers of peat. Peatlands arise because of incomplete decomposition of organic matter, usually litter from vegetation, due to water-logging and subsequent anoxia. Like coral reefs, peatlands are unusual landforms that derive mostly from biological rather than physical processes, and can take on characteristic shapes and surface patterning.

<span class="mw-page-title-main">Eastern Congolian swamp forests</span>

The Eastern Congolian swamp forests are a fairly intact but underresearched ecoregion of the tropical and subtropical moist broadleaf forests biome. It is located within the Democratic Republic of the Congo. This is the eastern half of one of the largest areas of swamps in the world.

<span class="mw-page-title-main">Southern Congolian forest–savanna mosaic</span>

The southern Congolian forest–savanna mosaic is an ecoregion that covers a large area of the southern Democratic Republic of the Congo and northeastern Angola. Its rich blend of habitats provides key insights into the biogeography of central Africa with the extensive climatic variation that it has been experiencing for the last 10 million years. The human population is not high.

Paludiculture is wet agriculture and forestry on peatlands. Paludiculture combines the reduction of greenhouse gas emissions from drained peatlands through rewetting with continued land use and biomass production under wet conditions. “Paludi” comes from the Latin “palus” meaning “swamp, morass” and "paludiculture" as a concept was developed at Greifswald University. Paludiculture is a sustainable alternative to drainage-based agriculture, intended to maintain carbon storage in peatlands. This differentiates paludiculture from agriculture like rice paddies, which involve draining, and therefore degrading wetlands.

<span class="mw-page-title-main">Northwestern Congolian lowland forests</span> Tropical forest ecoregion in Central Africa

The Northwestern Congolian lowland forests is a tropical moist broadleaf forest ecoregion that spans Cameroon, Gabon, the Republic of Congo, the Central African Republic and a minuscule part of the Democratic Republic of the Congo. It forms part of the larger Congolian rainforests region in Central Africa. The region is noteworthy for very high levels of species richness and endemism. It is home to a core population of the critically endangered Western lowland gorilla. There are also large populations of forest elephants.

The Global Peatlands Initiative is an effort made by leading experts and institutions formed in 2016 by 13 founding members at the UNFCCC COP in Marrakech, Morocco. The mission of the Initiative is to protect and conserve peatlands as the world's largest terrestrial organic carbon stock and to prevent it from being emitted into the atmosphere.

The Guineo-Congolian region is a biogeographical region in Africa straddling the Equator and stretching from the Atlantic Ocean through the Congo Basin to the Congo / Nile divide in Rwanda and Burundi. Formerly, this region was largely covered in rain forest, on both well-drained sites and in swamp forests, but little undisturbed primary forest now remains, having been replaced in many areas by savanna and secondary-growth forest.

<span class="mw-page-title-main">Cuvette Centrale Province</span> Province in Democratic Republic of the Congo

Cuvette Centrale Province was a province of the Democratic Republic of the Congo that existed between 1963 and 1966 during the Congo Crisis.

References

  1. 1 2 3 Dargie, Greta C.; Lewis, Simon L.; Lawson, Ian T.; Mitchard, Edward T.A.; Page, Susan E.; Bocko, Yannick E.; Ifo, Suspense A. (11 January 2017). "Age, extent and carbon storage of the central Congo Basin peatland complex" (PDF). Nature. 542 (Month 2017): 86–90. Bibcode:2017Natur.542...86D. doi:10.1038/nature21048. PMID   28077869. S2CID   205253362.
  2. 1 2 Lewis, Simon (13 January 2017). "Guest post: Vast carbon store found under Congo swamp forest". Carbon Brief. Retrieved 2023-01-15.
  3. 1 2 Lewis, Simon (2 November 2022). "Guest post: Discovering a potential 'tipping point' for Congo's tropical peatland". Carbon Brief. Retrieved 2023-01-15.
  4. Grossman, Daniel (2019-10-01). "Inside the search for Africa's carbon time bomb". National Geographic. Archived from the original on 2019-10-02. Retrieved 2019-10-11.
  5. "Historic agreement signed to protect the world's largest tropical peatland". UNEP - UN Environment Programme. 23 March 2018.
  6. Crezee, Bart; Dargie, Greta C.; Corneille, E. N. Ewango; Mitchard, Edward T.A.; Ovide, Emba B.; Kanyama T., Joseph; Bola, Pierre; Ndjango, Jean-Bosco N.; Girkin, Nicholas T.; Bocko, Yannick E.; Ifo, Suspense A.; Hubau, Wannes; Seidensticker, Dirk; Batumike, Rodrigue; Imani, Gérard; Cuní-Sanchez, Aida; Kiahtipes, Christopher A.; Lebamba, Judicaël; Wotzka, Hans-Peter; Bean, Hollie T.; Baker, Timothy R.; Baird, Andy J.; Boom, Arnoud; Morris, Paul J.; Lawson, Ian T.; Page, Susan E.; Lewis, Simon L. (21 July 2022). "Mapping peat thickness and carbon stocks of the central Congo Basin using field data". Nature Geoscience. 15 (August 2022): 639–644. doi: 10.1038/s41561-022-00966-7 . hdl: 10023/26809 . S2CID   250928067.
  7. Garcin, Yannick; Schefuß, Enno; Dargie, Greta C.; Hawthorne, Donna; Lawson, Ian T.; Sebag, David; Biddulph, George E.; Crezee, Bart; Bocko, Yannick E.; Ifo, Suspense A.; Wenina, Emmanuel Mampouya; Mbemba, Mackline; Corneille, E. N. Ewango; Ovide, Emba B.; Bola, Pierre; Kanyama T., Joseph; Tyrrell, Genevieve; Young, Dylan M.; Gassier, Ghislain; Girkin, Nicholas T.; Vane, Christopher H.; Adatte, Thierry; Baird, Andy J.; Boom, Arnoud; Gulliver, Pauline; Morris, Paul J.; Page, Susan E.; Sjögersten, Sofie; Lewis, Simon L. (2 November 2022). "Hydroclimatic vulnerability of peat carbon in the central Congo Basin". Nature. 612 (November 2022): 277–282. doi:10.1038/s41586-022-05389-3. PMC   9729114 . PMID   36323786.