Africa hosts a bewildering variety of ecosystems, with over 50,000 plant species and 1,100 mammal species (including almost 200 primate varieties), about 2,500 bird species and 1,000 amphibian species, and over 2,000 reptile species. It is also home to eight of the 34 “critical biodiversity reserves” listed by the NGO Conservation International.
But the threat posed to surviving species is enormous, given the massive global decline in plant and animal species, and accelerating degradation of ecosystems. To have a more detailed view of the degree of damage already done, and what to expect in the coming years, a team of experts from the Sahara and Sahel Observatory (OSS) and AFD has examined trends in Africa between 2005 and 2019.
Ecozone: a part of the earth’s land surface that is distinguished by its own evolutionary history and distribution patterns of life forms
Ecological deterioration
Experts used the ENCA method to assess more than 200,000 ecozones with an average surface area of 12 km by 12 km. Measurements of organic carbon in biomass and soil are used to calculate the Total Ecosystem Capacity (TEC) of an ecozone, which also incorporates water and the integrity of biodiversity. The TEC is expressed in ECU (Ecosystemic Capability Units), a non-monetary unit comparable to a tonne of CO2 equivalent.
A decline in the amount of TEC from 2005 to 2019, especially in the last five years, indicates continuous ecological deterioration. In such cases, the ecozone is classified as unsustainable in the long term. Conversely, stable or improving ecozones are considered sustainable. Along with the decline of water levels and soil fertility, are the rising amounts of carbon released into the air.
Of the continent’s 200,874 ecozones, only 39% are classified as sustainable, compared to 61% unsustainable, with breakdowns into moderate (24%), high (29%), and critical (7%). These degraded ecosystems are particularly concentrated in the north, west, and far south of Africa, as well as in Madagascar.
61% of ecozones unsustainable
The conclusions of the study, available in L’Économie africaine 2024, published (in French) in January, confirm the findings of biodiversity erosion in Africa. “Ecosystem capacity”, which measures the potential of ecosystems to provide their services over time and to renew themselves sustainably, fell by 5.6% over the period. While all African regions are affected by this decline, it is most pronounced in Madagascar (-13.9%), Southern Africa (-7.5%) and the Congo Basin (-6%).
750 million Africans affected
More than 750 million people now live in unsustainable ecozones, 157 million of them in areas where the threat is considered critical. Several consequences are likely, including a drop in economic production in areas that account for over half of Africa’s GDP, an increase in poverty, and a rise in migration.
Crucially, “a deteriorating environment is less resilient to climate change,” says Emmanuel Fourmann, AFD researcher and co-author of the chapter in L’Économie africaine. “Farmers cannot correct the ecosystem’s shortcomings indefinitely, raising the question of community subsistence."
These initial findings are obtained using ENCA tracking. “It’s a method that’s in its infancy,” says Emmanuel Fourmann. “If it proves its worth, it will make it possible to monitor the health of ecosystems and limit their degradation.” Nevertheless, the findings show that a great deal of work lies ahead to adapt regions and economies and try to slow down their ecological and economic desertification.
The introduction and first chapter of African Economies 2024 have been translated into English.
