Extreme heat is a potent and progressively worsening public health problem confronting West Africa, where heat stress remains “a silent killer”. Most heat deaths occur in cities, driven by the urban heat island effect. In wealthier cities, air conditioning is the primary means of adapting to extreme heat, but Sierra Leone has one of the lowest electricity access rates in the world, making this climate intervention unaffordable...

Using techniques commonly applied in participatory action research and ethnography, we examine 20 specific cases of experimentation for a selection of carbon removal and solar radiation modification interventions. These experiments include engineering-based approaches such as stratospheric aerosol injection, cloud brightening, carbon–neutral cement, biochar, direct air capture, and enhanced rock weathering alongside ecosystems...