The heat wave from the Sahara that is hitting southern Europe is also testing the countries of North Africa, where temperature records have been set, particularly in central Algeria and southern Morocco. What is perceived as a new phenomenon in the northern Mediterranean has already settled into a form of normalcy on the southern shore, explains Omar Baddour, head of the organization’s climate monitoring services and climate policy division. World Meteorological Service (WMO). But unlike Europe, the impact of these extreme climatic events on health and mortality remains unknown, due to a lack of statistical data.
The continent is governed by different climatic regimes, but in terms of heat waves, they mainly occur above the tropical line in the northern hemisphere, that is to say in the zone from Sahara to the Mediterranean. The heat wave that Europe is experiencing comes directly from the Sahara. Its consequences are less noticeable in the desert areas, which are already almost uninhabited apart from a few nomadic populations who cross them, than in the Mediterranean regions, where they pose real problems, particularly for agriculture.
We are talking about a deviation from the seasonal averages ranging from 4°C to 10°C. Warning bulletins have been issued by the meteorological services of several Maghreb countries due to temperatures reaching 47°C or 48°C. But unlike southern Europe, these temperatures have not been exceptional for several years, if not decades. North Africa is the fastest warming region of the continent. In the 1970s, 42°C was considered very hot. This is now a perceived value almost below the seasonal average in summer.
The impact of this phenomenon is complex and contrasting from one region to another. In East Africa, El Nino usually coincides with heavier rains from September, which is when the “small” rainy season begins in this area. This could relieve the countries of the Horn – Ethiopia, Somalia, Kenya – which have been suffering for several years from a prolonged drought, the cost of which is very high in terms of food insecurity, loss of herds and crops.
Our knowledge of its impact on North Africa is much less established. Many studies have been carried out without providing clear results. In the event of a pronounced El Nino phenomenon, however, it seems that this leads to a decrease in rainfall in the spring, which is the critical period for the growth of cereal crops. If this is confirmed, it is not good news.
Many changes are taking place in the Antarctic zone, on which the climate of southern Africa greatly depends. And we must admit that at the moment we do not understand the full scope of this. In the past, snowfalls have already occurred; and if they are unusual, they are nevertheless possible from a meteorological point of view. It is therefore difficult today to make a link with climate change.
While the 2003 heat wave made Europe aware of the need to acquire more efficient monitoring and measurement tools, this is not the case in Africa. As everywhere, it is the most vulnerable people who pay the highest price for heat waves, but there are no statistics of this additional mortality.
All African countries now have the means to anticipate waves of heat, cold or intense rainfall. There are reliable regional models. On the other hand, the impact of these extreme episodes is not measured. However, this should be a priority in order to be able to develop prevention and adaptation policies.
To do this, it is necessary to be able to couple climate models with data on health, on agricultural systems, on migration, etc. In Europe or the United States, for example, systems are used which make it possible to know the incidence of high temperatures. on health above certain thresholds. This means collecting local data over several years from the most vulnerable target populations.
The “Early Warning for All” program, launched in the spring by United Nations Secretary-General Antonio Guterres, and led by WMO, aims to fill this gap. It is essential to equip all countries, in particular the most vulnerable, with early warning systems to reduce the number of deaths and economic losses linked to extreme climatic events, which will multiply.
Africa remains the continent with the least dense observation network. Significant efforts have been made and it has become relatively easy to install automated weather stations even in remote locations. However, these stations require regular maintenance and calibration which has not always been ensured. As a result, thousands of stations are no longer in working order a few years later. It is not enough to equip the countries, we must provide training and capacity building programs so that they are able to maintain them. In the future, foreign donors who finance these programs should ensure this.
