Human-induced climate change made the humid heatwave in southern West Africa during February ten times more likely, according to a rapid analysis by an international team of leading climate scientists from the World Weather Attribution.
The study also found that if humans do not rapidly move away from fossil fuels, which is causing global warming to rise to 2°C above preindustrial levels, West Africa will experience similar heatwaves about once every two years.
In February, West Africa was hit by an unusually intense humid heatwave with temperatures not normally seen until March and could likely last till April. The most severe heat occurred from February 11-15 with temperatures above 40°C.
According to Wasiu Adeniyi Ibrahim, Head, Central Forecast Office, NiMet, Abuja, Nigeria, the February heatwave occured early in the year, meaning many people wouldn’t have been acclimatised to the heat.
“It is clear climate change is bringing more and more dangerously hot days to West Africa. With every fraction of a degree of global warming, heatwaves like the one we experienced in February in West Africa will become even hotter,”.Ibrahim noted.
In Nigeria, doctors reported an increase in patients with heat-related illness, as people complained of poor sleep due to hot nights. The National Meteorological Agency issued several warnings about the heat.
In Ghana, the national meteorological agency also warned people to prepare for dangerous temperatures.
Climate change, caused by burning fossil fuels like oil, gas and coal, and deforestation, has made heatwaves more frequent, longer and hotter around the world.
To quantify the effect of climate change on the hot and humid temperatures in West Africa, scientists observed weather data and climate models to compare how the event has changed between today’s climate, with approximately 1.2°C of global warming, and the cooler pre-industrial climate, using peer-reviewed methods.
The analysis looked at the maximum five-day heat index in a region of southern West Africa where the heat was most extreme, including Nigeria, Benin, Togo, Ghana, Côte d’Ivoire, Liberia, Sierra Leone, and small parts of Guinea and Cameroon.
The heat index, also known as apparent temperature, is a measure that combines temperature and humidity to reflect how heat feels to the human body because higher levels of humidity make it harder for humans to cool down.
While the average air temperature in West Africa was above 36°C, the heat index for the same period was about 50°C, reflecting how a combination of humidity and high temperatures caused dangerous conditions.
The researchers found that climate change made the heatwave as measured by the heat index about 4°C hotter and ten times more likely. Before humans started burning fossil fuels, similar heatwaves used to be rare events, occurring less than once every 100 years.
However, in today’s climate, with 1.2°C of warming, similar humid heatwaves occur about once every 10 years.
According to the report, If the world does not move away from fossil fuels and rapidly reduce emissions to net zero, West Africa will experience even hotter and more frequent humid heatwaves.
If global warming reaches 2°C, as is expected to occur in the 2040s or 2050s unless emissions are rapidly halted, similar events will occur about once every two years and will become a further 1.2-3.4°C hotter.
Although the heatwave potentially affected millions across the nine countries, there were few heat-related impacts reported by the media and government organisations which reflects the need to improve awareness of dangerous heat and the detection of heat impacts.
While meteorological organisations in Nigeria and Ghana did provide warnings about the heat, many of the other countries included in the analysis have not carried out plans on coping with dangerous heat, including introducing early warnings for dangerous heat.
In addition, none of the countries have developed a heat action plan that is extremely effective at saving lives
during periods of dangerous heat.
The UN has estimated that the cost of adaptation for developing countries is between US$215-387 billion per year this decade.
However, rich countries haven’t yet met the financial commitments they have made to help developing countries become more resilient to the growing risks of climate change.
In addition, these commitments fall drastically short of the finance required. In 2021, the global community delivered just US$21 billion to help developing countries adapt to climate change.
Developing heat action plans will help protect vulnerable people from dangerous heatwaves in West Africa, the researchers say.