For a long time, the fate of the Congo basin appeared as a secondary concern to the urgency of stopping the destruction of the forests of the Amazon or Indonesia, forcibly converted into oil palm plantations, soybean fields or vast pastures for the cattle. breeding.
This time seems to have passed. Several large-scale scientific programs have just been launched, such as the Congo Basin Science Initiative (ISBC), equivalent to the project carried out twenty-five years ago in the Amazon to understand the functioning of the largest tropical forest. Called the Large-Scale Biosphere-Atmosphere Experiment in the Amazon (LBA), it mobilized hundreds of researchers, had a budget of 200 million dollars (190 million euros) and helped train a new generation of local scientists.
On the sidelines of the global climate conference (COP29), which ended on November 24 in Baku, Azerbaijan, the British government announced funding of almost $12 million for the Congo Basin initiative. It’s a start. “Everyone understood that we must invest in science. African forests remain the least studied despite their crucial role in climate regulation. To understand the current impacts of warming and anticipate the future, we need scientific data.”welcomes Raphaël Tshimanga, professor at the University of Kinshasa and co-president – together with Simon Lewis (University of Leeds) – of the ISBC.
The work carried out by the latter in the peatlands located in the north of the Congo and in the Democratic Republic of the Congo (DRC) has contributed to making the region visible. These formations, more than 10,000 years old, are the largest on the planet in a tropical environment and constitute a gigantic carbon reserve, which represents the equivalent of three years of greenhouse gas emissions on a global scale. The rapid deterioration of the sequestration capacities of the Amazon massif, particularly under the effect of severe droughts, has also fortuitously given publicity to the performance of African ecosystems.
Threatened carbon sink
In 2020, an article appeared in Science Under the direction of Wannes Hubau, a researcher at the Royal Museum of Central Africa in Brussels, he announced that African forests today have a greater sequestration capacity than the Amazon, although their function as a natural sink is weakening with deforestation. These results are based on measurements of the biomass present in 565 plots of approximately 1 hectare of so-called intact forests, distributed in the Amazon and Africa and carried out at regular intervals over a period of thirty years until 2015.
One of the ISBC’s objectives is to carry out a new survey campaign in the Congo Basin. “They are expensive and difficult missions because you have to reach plots located in remote areas and measure all the trees whose diameter is greater than 10 cm and then deduce the stored carbon. All scientists wonder. Is the African rainforest following the path of the Amazon? explains Adeline Fayolle, a specialist in the ecology of Central African forests, while pointing out the insufficient number of measurement points. These are a few points – about 200 – spread over an immense territory. »
The International Center for Agricultural Research for Development (CIRAD), to which the Gabon-based researcher is attached, participates in the other scientific initiative launched in 2023: One Forest Vision, funded by France with 15 million euros. whose ambition is also to improve the region’s observation system.
Scientists are watching for these tipping points at which forest ecosystems, under the combined pressure of human activities and climate change, could no longer play the role of carbon sinks. So far, African forests have shown greater resilience and capacity for regeneration.
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“They don’t have the same history. They have long adapted to greater variability between the dry season and the wet season. They have also been inhabited longer. This should lead to handling these notions of thresholds with nuances.”warns Bruno Hérault, from CIRAD, who works on the reconstitution of degraded forests in Africa.
In Yangambi, in the Democratic Republic of the Congo, in what was the largest agronomic center in the region during colonial times, a 55-meter-high flow tower has recorded net exchanges of CO for four years.2 between the canopy and the atmosphere. So far it is the only station in all of Central Africa, but three more should be installed: two in the Democratic Republic of the Congo, in the swamp forests near Mbandaka and in the forested savannahs of Lubumbashi; a third in the humid forests of the Dja reserve in Cameroon. Several million euros are needed to build these infrastructures and ensure their long-term maintenance.
“These stations give us the most accurate information. We can see how trees respond to rising temperatures or a change in precipitation. They are also valuable for integrating local parameters into global forecast models and thus making them more reliable. But in reality we are only at the beginning of this work.”explains Pascal Boeckx, professor at Ghent University, who led the Yangambi project.
The Democratic Republic of the Congo, the largest emitter of CO2 from the continent
The pressure on scientists is great. “Financials need simple indicators, but we are facing very large and very complex ecosystems”recalls Adeline Fayolle. Because behind these growing research budgets, the creation of carbon markets to remunerate forest protection policies is also at stake.
During COP29 in Baku, States approved the final details of Article 6 of the Paris Agreement, which regulates carbon credits linked to the reduction of greenhouse gas emissions and authorizes their transfer to other countries so they can achieve their goals. climatic. The credibility of this market depends, first of all, on the reliability of the data used.
All countries in the region plan to use these market mechanisms. Like Gabon, to reward the net carbon absorption of its forest cover, or like the Democratic Republic of the Congo, to reward its efforts in the fight against deforestation. The giant of 100 million inhabitants loses around 500,000 hectares of forest each year, the equivalent of one French department on average. This decline in forests, linked mainly to slash-and-burn agricultural practices and the use of wood as a source of energy, makes the Democratic Republic of the Congo the continent’s largest emitter of greenhouse gases, ahead of South Africa and its coal-fired power plants.
