The three-day downpour that struck the Gulf of Guinea coast in late June, killing at least 98 people and displacing thousands, was made roughly five times more likely by human-caused warming, according to a rapid attribution analysis by the World Weather Attribution group. The researchers, based at Imperial College London, found that the intensity of such heavy rainfall events has increased by 23% since record-keeping began, and that a similar deluge can now be expected every two to four years in a climate 1.4C hotter than pre-industrial levels.

Warmer air holds more moisture, and the study showed that greenhouse gas emissions directly intensified the rainfall by about 4% when comparing historical observations with climate model simulations. The lead author noted that climate models often struggle to capture tropical precipitation trends, making the detected signal significant. The floods overwhelmed drainage systems from Lagos to Monrovia, submerging neighbourhoods and infrastructure, with Côte d’Ivoire, Ghana, Togo and Nigeria worst affected.

The findings land as the World Health Organization faces pressure from a high-level commission to declare climate change a “public health emergency of international concern.” The commission points to a Lancet study reporting 63,000 annual heat deaths in Europe, and Dutch authorities recorded 911 excess deaths during a June–July heatwave that pushed temperatures near 40C, with the elderly and those in the south and east most vulnerable. However, analysts in Accra note that the European mortality figures are not age-standardised; Europe’s over-70 population has grown by 78% since 1990, and the Global Burden of Disease database shows age-adjusted heat death risk has changed only marginally. The same analysis indicates that cold-related deaths in Europe have nearly halved over the same period, a decline roughly 250 times larger than any increase in heat deaths.

Viewed from West Africa, the attribution study reinforces calls for industrialised nations to fund adaptation in regions that contributed little to emissions. The WHO commission’s prescription, critics argue, risks raising energy costs and worsening both heat and cold vulnerability. The debate is set to intensify as the WHO’s executive board considers the emergency declaration recommendation in the coming months.