Tropical Forest Soils in a Warmer World: Consequences for Climate and Biodiversity

Climate warming poses detrimental but poorly understood consequences for tropical forest biodiversity and carbon storage, especially through its impact on soils. To address this uncertainty, the Soil Warming Experiment in Lowland Tropical Rainforest (SWELTR) was initiated on Barro Colorado Island in Panama; one of a few emerging experiments designed to understand the effects of a warmer climate on the tropical land-surface. In this chapter, I describe results following up to three years of experimental whole-profile soil warming, showing high sensitivity of soil organic matter degradation and an unexpectedly large release of carbon dioxide (CO₂) to the atmosphere. I consider the biogeochemical mechanisms that may be contributing to this CO₂ emission and, finally, the research priorities to understand the longer-term and wider-scale implications of warming on tropical forest soils. Better understanding of these feedbacks is vital for developing mitigation strategies to conserve the biodiversity and carbon storage of tropical forests in a warming world.