Summary/Abstract
The southern coastal zone of Western Africa – also called the Guinea zone – experienced abnormal early season heat in February 2024. A combination of high temperatures and relatively humid air resulted in area average Heat Index values of about 50°C, which is classified to be in the ‘danger’ level that is associated with a high risk of heat cramps and heat exhaustion. Locally, values even entered the level of ‘extreme danger’ that is associated with high risk of heat stroke, with values up to 60°C.
This real-time event attribution study evaluates the degree to which human-induced climate change has influenced the occurrence of high temperatures in West Africa. Using a combination of climate models and observations, the authors estimate the influence of human-caused climate change on this excessive humid heat. The authors find that because of human-induced climate change, the area-averaged heat index is about 4°C higher in today’s 1.2°C warmer climate. In addition, the authors find that humid heatwaves, like those experienced in the Guinea zone, have become at least 10 times more likely in the current climate. The study characterizes the average 5-day humid heat experienced in the Guinea zone as a 1-in-10 year event in today’s climate. Further, the authors estimate that at global mean temperatures of 2°C above pre-industrial levels, similar events will occur about once every two years.