The heart of Africa’s climate: understanding the Congo Basin

By Jean Baptiste Ndabananiye

In the intricate tapestry of our planet’s ecosystems, few threads are as vital as those woven by the world’s great forests. Spanning from the dense canopies of the Congo Basin to the sprawling expanses of the Amazon, these forests do not just form magnificent landscapes but are also crucial guardians of our climate. This constitutes the second article of “Echoes of the Earth: From the Congo Basin to the Amazon,” a reporting project— by Life In Humanity—that explores the vital role of these forests in sustaining global ecosystems, regulating climate, and supporting local communities. This project highlights the critical need for urgent action to protect these forests, emphasizing that their preservation is essential not only for the world’s biodiversity but also for humanity’s future. The first article can be reached here.

In this piece, “The heart of Africa’s climate: understanding the Congo Basin,” we will explore the pivotal role of the Congo Basin in regulating climate and stabilizing rainfall, not only in Africa but across the globe. As we examine the size, scope, and countries encompassed by this vital region, we will uncover how its rich biodiversity and unique environmental dynamics influence weather patterns throughout East Africa, including Rwanda. Furthermore, we will highlight the Basin’s significant contribution to carbon sequestration, a critical component in our collective fight against climate change. Join us as we embark on this journey to understand how the life of the Congo Basin resonates far beyond its borders, shaping the future of our planet. The article consists of these essential components:

1. Introduction to the Congo Basin
2. Carbon sequestration and climate mitigation
3. What would happen, if the Congo Basin forest were eliminated?

Introduction to the Congo Basin

The Congo Basin is home to the second largest tropical forest after the Amazon Basin. The former basin represents roughly 70% of Africa’s forest cover. It lies in six countries namely Cameroon, Congo, Gabon, Equatorial Guinea, Central Africa Republic (CAR) and Democratic Republic of Congo (DRC). The forest cover on the side of the DRC exceeds 166 million hectares and alone represents more than 62% of the Congo Basin forest. This basin stretches over 2 million sq km,  an area roughly the size of Europe.  Our first article indicates that there exist other countries which share in the basin, some of them being Rwanda, Burundi and Tanzania.

World Wildlife Fund (WWF) in its 22 June 2024 story “5 things to know about the Congo Basin Rainforest”says “As 22 June marks World Rainforest Day, WWF stands as a committed partner and critical player uniting to ensure a better forest future for Africa – and celebrating Africa’s iconic and invaluable Congo rainforest ecosystems. The Congo Basin Forest: a vital ecosystem.

The Congo Basin forest, spanning six Central African countries, is not just the largest tropical forest on the continent, but also the second-largest in the world. The Congo rainforest, covering a staggering 300 million hectares, is a unique and vital ecosystem, even when compared to the 800-million-hectare Amazon. Three global tropical forests. Across the world, three major regions – the Amazon, the Congo and the Borneo-Mekong-South-East-Asia basins – collectively account for 80% of the world’s remaining tropical forests. Together, they are also home to two-thirds of terrestrial biodiversity.”

Carbon sequestration and climate mitigation

In its 24^th October 2022 story, the World Bank calls the Congo Basin the lungs of Africa and beating heart of the world. It says “Known as the ‘lungs of Africa’, the Congo Basin is the largest carbon sink in the world, absorbing more carbon than the Amazon.”

The Congo Basin rainforest is estimated to absorb extremely huge tons of carbon dioxide annually. This basin not only stores carbon in massive quantities but also removes more carbon from the atmosphere than it emits, acting as a net carbon sink.

The World Bank’s statement highlights not only the Congo Basin’s crucial role in capturing atmospheric carbon but also emphasizes its unique value in mitigating climate change on a global scale. This role solidifies the basin as a vital global carbon sink and an essential resource in climate resilience efforts.

“Preserving the Congo Basin forests is vital not just for the future of Africa, but for that of the world. Global efforts to tackle the effects of climate change and biodiversity loss will depend on preserving this rich and lush ecosystem.  Gabon annually absorbs carbon emissions equivalent to a third of France’s annual total. The Republic of Congo alone absorbs 1.5% of the world’s entire annual carbon emissions,” states the World Bank.

“Climate actions are needed to help countries in the Congo Basin to pursue green, resilient, and inclusive development that allow them to conserve their natural resources while sustaining livelihoods and boosting economic diversification.”

Within the basin occurs one of the world’s largest tropical peatlands, discovered in the Cuvette Centrale region of the DRC and Republic of Congo. These peatlands alone store billions of tons of carbon, helping to counteract global fossil fuel emissions. Peatlands are unique ecosystems that sequester and hold large amounts of carbon over thousands of years, making them exceptionally efficient carbon sinks. The Cambridge Dictionary defines peatland as an area of land mostly comprising a dark brown substance like soil that has been formed by plants dying and becoming buried. According to Mongabay- Conservation News, partially decomposed plant matter is known as peat.

Also underscoring the gargantuan importance of the Congo Basin, the UN Environment Program (UNEP) with its 27 February 2023 article places the Congo Basin peatlands among critical ecosystems.

The UNEP says “The Congo Basin is home to the world’s largest tropical peatlands, along with Brazil and Indonesia. The peat swamp forest of the Congo Basin stores around 29 billion tons of carbon – approximately equivalent to three years’ worth of global greenhouse gas emissions – while the Basin as a whole absorbs nearly 1.5 billion tons of carbon dioxide a year.”

The 29 billion tons of carbon stored in the Congo Basin’s peatlands constitutes a cumulative amount. It means that this carbon has been sequestered over thousands of years and remains “locked” in this ecosystem, preventing it from entering the atmosphere. In summary, the 29 billion tons represent the historical, accumulated carbon storage, while the 1.5 billion tons represent the basin’s yearly sequestered carbon quantity from current emissions.

This highlights the Congo Basin’s powerful role in global climate regulation through its carbon storage and absorption capacity. The immense quantity of carbon kept “locked” in the basin’s peatlands prevents this gas from contributing to atmospheric warming.

Doreen Robinson, the UNEP Head of Biodiversity and Land says “The Congo Basin is one of the world’s last regions that absorbs more carbon than it emits.” The UNEP adds “Peatlands are an effective carbon sink – they absorb more carbon from the atmosphere than they produce. Carbon sinks are essential to combating the climate crisis and protecting planetary health.

The climate crisis causes more frequent extreme weather events that worsen food and water scarcity, hinder global economies, and threaten human well-being. With human-caused greenhouse gas emissions forecast to rise, ensuring urgent cross-sector action and protecting and sustainably managing peatlands is considered crucial.”

The UNEP explains that peatland ecosystems fulfill a major role in mitigating the climate crisis. “They house and protect rare and vital nature and offer resilience through water capture, storage and much more. Protecting and restoring the peatlands that are already degraded can reduce global greenhouse gas emissions by 800 million metric tons per year.

Peatlands cover only 3 per cent of the global land surface but store an estimated 600 billion tons of carbon – twice as much as in all the world’s forests. This makes them one of the most efficient carbon sink ecosystems and underlines the need to protect them, experts say. Plants absorb carbon during the process of photosynthesis, which they use to convert into wood, leaves and roots. Because peatlands are water-logged, plant matter takes longer to decompose. This traps more carbon and provides a net-cooling effect.”

Climate regulation and rainfall in various parts of Africa

NORCE, Norwegian Research Centre, has conducted research that has investigated “Effects of the Congo Basin Rainforest on Rainfall Patterns.” The report has been commissioned by the Norwegian Environment Agency. The research report published in October 2023 reads “Much of the moisture from evapotranspiration in the Congo rainforest is recycled and contributes 25%–85% of the annual rainfall within the Congo Basin. Moisture from the Basin also provides about 40% of the Sahelian Sudan annual rainfall and almost half of the Ethiopian highland rainfall during June–August.”

Nature released a thorough article titled “Drivers and impacts of Eastern African rainfall variability” on 21 March 2023. This article was written by around 20 prominent authors from various great institutions including the University of Edinburgh in the UK. It reads “Eastern Africa exhibits bimodal rainfall consisting of long rains (March–May) and short rains (October–December. Seasonal rainfall is integral to the 457 million people living across Eastern Africa, a region including Burundi, Djibouti, Eritrea, Ethiopia, Kenya, Rwanda, Somalia, South Sudan, Sudan, Tanzania and Uganda.

The most northerly and southerly regions (northern Ethiopia, Eritrea, Sudan, South Sudan and southern Tanzania) experience a single summer wet season for their respective hemispheres. In contrast, countries between these latitudinal extremes (encompassing Kenya, Uganda, Somalia, Burundi, Rwanda and parts of northern Tanzania and southern Ethiopia) experience two wet seasons. These two wet seasons occur during boreal spring (typically March–May, MAM; the more intense long rains) and autumn (typically October–December, OND; the less intense short rains), although there are substantial regional variations in these timings.”

This article underscores that seasonal rainfall stands vital to the health and economic prosperity of the region. For example, it clarifies, long rains foster agricultural production and thus national food security. “Rain-fed agriculture, in turn, has a substantial role in the economy of many Eastern African countries. Agriculture employs 67% of people in Ethiopia, 80% in Somalia, 54% in Kenya, 63% in Eritrea and 38% in Sudan. Agriculture also represents an extensive contribution to the annual multibillion-dollar export of goods such as sugar, tea, coffee, tobacco, nuts and seeds, cut flowers and vegetables.

Moreover, rainfall is pivotal to energy production, particularly given that hydropower represents a large fraction of electricity generation in Eastern Africa. Aquifer recharge from rainfall also provides a sustainable reservoir of groundwater for potable water (and irrigation) during periods of drought, demonstrating the importance of rainfall for water security, especially when looking to the future.”

In explaining the role of atmospheric dynamics in East African rainfall patterns, the authors of the article highlight the Congo air mass’ critical impact on the seasonal long rains. They describe how fluctuations in zonal wind patterns from the Congo basin drive substantial inter-annual variability in rainfall totals, especially during the March–May period. “The influence of the Congo airmass, characterized by 700-hPa zonal winds, has also been associated with interannual variability of the long rains.

Despite climatological easterly winds, westerly winds originating from the Congo sometimes occur during March–May (often linked to phase 3–4 of the MJO), bringing moist air that leads to convergence around Lake Victoria and enhances rainfall. Indeed, the cumulative rainfall total of the long rains is further strongly correlated with 700-hPa zonal winds across the Congo basin and Gulf of Guinea. Furthermore, enhanced surface westerlies from the Congo basin, driven by a higher geopotential height gradient over the Congo basin than the western Indian Ocean, lead to wetter long rains over Tanzania.”

What would happen, if the Congo Basin forest were eliminated?

The elimination of the Congo Basin rainforest would trigger a chain reaction of ecological, climatic, and social consequences with profound, lasting effects on both local and global scales. It would disastrously affect the environment, climate, biodiversity, and human populations.

As previously noted, one of the most severe consequences of eliminating the Congo Basin rainforest would be a significant reduction in rainfall across regions that rely on this giant forest. This reduction would, in turn, disrupt key sectors, especially agriculture. The forest plays a crucial role in regulating local water cycles, influencing humidity and rainfall across the region. Without it, the region could experience increased droughts, soil erosion, and reduced water quality, negatively affecting agriculture and making it harder for communities to sustain their livelihoods.

NORCE states “A complete removal of the Congo rainforest would lead to a delay in rainfall onset, a shorter rainy season and a change in the spatial distribution of the rainfall both within the Congo Basin and the surrounding countries.

These rainfall characteristics are critical to the agricultural sector and any change could impact crop yields. In Ethiopia, a 5-day delay in rainfall onset could lead to a loss of 1.5% in crop production, while a 5-day shorter rainy season decreases the production by 1.1%.”

As also elucidated, the Congo Basin rainforest constitutes the world’s largest carbon sink, absorbing vast amounts of carbon dioxide. Without it, massive amounts of this gas would be packed into the atmosphere, exacerbating global warming. The loss of this forest would also impede regional and even global rainfall patterns, leading to unpredictable climate changes that could hamper agriculture and water availability far beyond Central Africa. Economics Observatory says “Conserving the Congo Basin is essential for preserving biodiversity and averting climate catastrophe.”

The Congo rainforest supports an extraordinary array of wildlife, including several endangered species like forest elephants, lowland gorillas, okapis. Other most famous residents of the forest involve chimpanzees, leopards, hippos, and lions. This forest is renowned for not less than 600 tree species and 10 000 animal species.

Its elimination would result in the extinction of numerous species, disrupting ecosystems and reducing global biodiversity. Economics Observatory in its 3 September 2024 points out “The Congo Basin is an extraordinarily diverse ecosystem.

There are over 10,000 species of tropical plants – 30% of which cannot be found anywhere else on earth. Around 400 different mammals and 1,000 species of bird call the basin their home. Below the surface of the river live more than 700 species of fish (Harrison et al, 2016). The number of insects is greater still, with the area boasting 370,000 species of beetle alone and 550 different types of butterfly.”

Millions of people rely on the forest for food, medicine, shelter, and income. The loss of the forest would devastate these communities, leading to economic hardship, displacement, and loss of traditional knowledge tied to the forest’s resources. GreenPeace says “Today, 75 million people from over 150 distinct ethnic groups depend on the health of the forest that covers much of the Congo Basin peatland complex.”