Is the Climate of the Congo basin Becoming Less Able to Support a Tropical Forest Ecosystem?

Abstract

Abstract Ongoing degradation of the Congolese rain forest is documented, but the individual roles of climate change and deforestation are unknown. A modified version of the Centro de Previsao de Tempo e Estudios Climaticos (CPTEC) potential vegetation model (PVM) forced by ERA5 reanalysis data translates decadal climate states (1980–2020) into natural vegetation distributions to identify regions where climate change could have played a role in changing vegetation. These areas are then examined to understand how and why these climate changes could affect the tropical rain forest coverage. Between the 1980s and the 2010s, the climate over the northern and southern Congo basin rain forest margins becomes less able to support the forest. In the north, strong, negative meridional moisture gradients in boreal winter separate warm, dry conditions to the north from the cooler, moist rain forest. By the 2010s greenhouse gas warming deepens the low-level trough in the north, enhancing the inflow of drier subtropical air. A similar drying response occurs over the southern margin during austral winter when the low-level westerly transport of Atlantic moisture decreases in association with warming and reduced low-level heights over the equatorial Congo basin. In the interior, climate conditions also become less favorable along major transportation routes by the 2010s due to human intervention/deforestation. Along coastal Angola, the climate becomes more favorable for tropical forest vegetation when coastal upwelling weakens and SSTs warm in response to changes in the South Atlantic subtropical anticyclone. These results have implications for the future as global warming continues.