Extreme heat is a serious danger for people’s health. It affects the cardiovascular system and is especially dangerous for the elderly and people with pre-existing health conditions.
Recent research found that extreme heat has become more frequent and lasting longer in almost all regions of the world since the 1950s. The largest increases were seen in the Middle East, South America and parts of Africa.
Because societies in different parts of the world are adapted to varying average temperatures, there is no universal definition of which temperature range qualifies as extreme. For example, in the UK temperatures above 25 ° C are rare, while the Indian Meteorological Service is only consider temperatures above 40⁰C as hot.
But almost everywhere, thresholds are now being exceeded more and more days at a time.
More worrying is that climate projections show that such heat waves across the African continent will become warmer and more dangerous, even if global warming kept below 1.5 ° C. Extremely strong increases in extreme heat are forecast in East and Southern Africa.
Given population changes, the number of people exposed to dangerous heat in African cities is expected to increase by the end of the century at least 20 times more. Yet extreme heat waves are not systematically monitored in many countries in sub-Saharan Africa.
As we explain in a recent newspaper, this means that the effects of extreme heat are reported below, which is driving even more people into trouble.
In most sub-Saharan African countries there are no early warnings and no heat action plans. Unnecessary, premature deaths are not counted. And there is very few adjustment attempts for the fastest growing danger in a changing climate.
Gaps in the records
There is an almost complete absence of reported heat wave events in sub-Saharan Africa in disaster databases. The largest of these databases, EM-DAT, lists technological and environmental disasters around the world. It contains events such as earthquakes and oil spills and their impact on lives, livelihoods and economies.
EM-DAT has contained only two heat waves in sub-Saharan Africa since 1900. This resulted in 71 early deaths. In contrast, 83 heat waves have been recorded in Europe in the last forty years alone. Other inventories of weather-related disasters contain similar differences.
Heat waves in Africa are not reported by governments, weather services or public health agencies, although they do occur naturally. Exposure and vulnerability to extreme weather are also more pronounced in many sub-Saharan countries compared to European countries. This is mainly due to higher poverty levels, informal settlements and the need for outside work.
Therefore, there are likely to be an even greater number of premature deaths due to severe heat. But they have never been registered, so the number is unknown.
Reporting and observation
A lack of reporting on deaths related to heat waves means there is little awareness that extreme heat can be deadly. It was only after the European heat wave in 2003 more than 70,000 people killed that countries and cities have started plan for such times.
The Indian city of Ahmedabad a heat wave plan implemented after an extremely hot and deadly pre-monsoon season in 2010. This led to the country reporting fewer deaths after an even more severe heat wave in 2015.
This type of planning is impossible if heat waves are not recorded.
Since heat wave deaths are rarely reported in sub-Saharan Africa, we do not know the exact temperature thresholds that result in heat-related deaths. However, this information is crucial for local communities to adapt.
In Ahmedabad, for example, the the average daily maximum temperatures are usually around 40 ° C in April and May. In Western Europe such temperatures would exist a severe heat wave. The consequences would be fatal if the temperature remained at this level for several consecutive days.
One reason for this unequal reporting of extreme heat lies in the fact that entities report the impact of extreme weather. In most developed countries, national governments provide numbers on people affected, death rates and even economic losses for extreme weather conditions. But for many lower-income countries, these reports are provided by various NGOs as an unsystematic by-product of their disaster relief.
Reporting standards differ depending on the NGOs and are usually little or not related to meteorological services. There is no central place that records the nature of the event and its impact.
Another reason why heat waves are not reported may be that they can occur in combination with droughts. This can often lead to food insecurity and humanitarian crises. Most observations and response mechanisms developed by NGOs and governments have thus been adapted to the negative effects of drought.
What to do
In our paper, we have identified several key areas where improvements can take place quickly.
First, early warning systems and heat action plans can be beneficial. Initially, they may need to be based on information from other countries with a similar climate. More analysis of historical periods of extreme heat in sub-Saharan Africa from a purely meteorological point of view, can help to compile a useful definition of heat waves for the region and improve warnings.
Second, collaboration between local researchers, hospitals and epidemiologists can identify direct health consequences of extreme heat. There were successful pilot projects in Ghana and The Gambia.
Heat waves are killers. But relatively simple measures such as opening public buildings for cool rooms, distributing free drinking water, informing people about the dangers of heat and early warning can dramatically reduce the danger.
By combining data with local expertise, the effects of heat waves can be understood and future risks minimized, although the danger itself increases.
Luke Harrington, Postdoctoral Researcher in Climate Extremes, Environmental Change Institute, University of Oxford and Friederike Otto, Co-Director, Environmental Change Institute, University of Oxford