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Five of Africa’s top 30 deadliest weather disasters have occurred since 2022 » Yale Climate Connections

Over the past year, Africa has experienced five of its top 30 deadliest weather disasters since record-keeping began in 1900, according to statistics from EM-DAT, the international disaster database. That includes deaths from Cyclone Freddy, which made landfall in Mozambique on March 11, 2o23, as a Category 2 storm with 110 mph winds, causing flooding now blamed for 1,434 deaths. Many of the recent disasters affecting the vast continent can be blamed on human-caused climate change, research has found.

Cyclone Freddy was the deadliest tropical cyclone on record for Africa, surpassing Cyclone Idai of 2019. Freddy left 679 dead and 537 people missing and presumed dead in Malawi, with additional fatalities in Madagascar (17), Mozambique (198), Zimbabwe (2), and Mauritius (1). Freddy is now the second-deadliest tropical cyclone in the entire Southern Hemisphere, behind an unnamed 1973 cyclone in Indonesia which killed 1,650.

In addition to Freddy in 2023, recent deadly disasters include four from 2022: drought in Uganda (2,465 deaths), flooding in West Africa (876 deaths, 603 of them in Nigeria), flooding in South Africa (544 deaths), plus one disaster EM-DAT does not list: drought in Somalia, which led to 43,000 excess deaths, according to a February 2023 study by the London School of Hygiene & Tropical Medicine. That study warned that the rate of fatalities could rise and predicted an additional 18,100-34,200 drought deaths in Somalia during the first half of 2023.

Climate change is increasing the severity of African weather disasters

Innovations in climate science have made it possible for scientists study whether human-caused climate change influenced a specific disaster, a field known as attribution science.

Read: Keeping up with fast pace of attribution science

A human climate change influence has been found via scientific attribution studies in more than 20 African extreme weather events since 2000, including 13 droughts, seven floods, and two heat waves.

The most recent of these studies, by the World Weather Attribution group, was completed in April 2023 for the 2020-22 drought in East Africa. The study concluded: “Climate change has made events like the current drought much stronger and more likely; a conservative estimate is that such droughts have become about 100 times more likely.”

This finding was mostly related to rising temperatures, which help dry out the landscape and exacerbate the impacts of any drought when it does occur. The 2020-22 rainfall deficit was largely a product of La Niña and a phenomenon known as a negative Indian Ocean Dipole, both of which are difficult to foresee in climate models (see our post of April 24). There is also some evidence of a long-term decrease in rainfall during the “long rains” period (March-May).

Climate change is also increasing the odds of extreme rainfall events; a May 2022 study by the World Weather Attribution group reported that for the South African floods of 2022 that killed 544 people, “We conclude that greenhouse gas and aerosol emissions are (at least in part) responsible for the observed increases [in rainfall].”

A separate study for the summer 2022 floods in West Africa that killed 876 people concluded that human-caused climate change made the event “about 80 times more likely and approximately 20% more intense.” 

Climate change also made Cyclone Freddy’s deadly heavy rains more likely, though there is no specific attribution study for this event yet. One of the more confident predictions hurricane scientists can make on the future of tropical cyclones in a warmer climate is that they will dump heavier rains due to increased moisture in the atmosphere. For example, a World Weather Attribution group study on flooding from two 2022 tropical cyclones in Madagascar, Mozambique, and Malawi concluded: “Greenhouse gas and aerosol emissions are in part responsible for the observed increases [in rainfall].” The 2022 IPCC report said that for southeastern Africa, where Freddy made landfall, “tropical cyclones making landfall are projected to become less frequent but have more intense rainfall and higher wind speeds at increasing global warming.”

A 2023 report from the United Nations Office for Disaster Risk Reduction found that disasters between 2015-2021 cost Africa 12.3% of its GDP, and stated “This is a significant amount of loss, bringing harsh economic consequences, major disruptions to national, regional and international markets, with far-reaching impacts on the socioeconomic well-being of its citizens. This demonstrates the exceptional challenges countries in Africa face, and how the impacts of disasters have a disproportionate burden for developing countries, not least regarding climate-related disasters.”

Read: How climate change is affecting Africa

According to the 2022 IPCC report, Africa has “experienced widespread losses and damages attributable to human-induced climate change, including biodiversity loss, water shortages, reduced food production, loss of lives and reduced economic growth.” The report projected a challenging extreme weather future for Africa, with extreme heat waves, droughts, and heavy precipitation events all expected to increase, saying, “most African countries will enter unprecedented high-temperature climates earlier in this century than generally wealthier, higher latitude countries, emphasizing the urgency of adaptation measures in Africa.”

Unfortunately, adaptation to increasingly severe climate conditions is not well funded. Between 2014-2018, less than $4 billion per year in international climate adaptation financing was provided to Africa, which needed $7-15 billion per year of such funding as of 2020. Assuming the Earth warms by just over 2 degrees Celsius above preindustrial levels, $18–60 billion per year in adaptation funding for Africa will be needed by 2050.

Freddy had a high indirect death toll

The aftermath of a major tropical cyclone often results in a huge number of indirect deaths — people who don’t die due to the direct impact of the storm’s winds and floods, but from malnutrition, infectious disease, lack of medicine, and other causes. For example, when Hurricane Maria hit Puerto Rico and the U.S. Virgin Islands in 2017, the storm was blamed for approximately 65 direct deaths. However, multiple studies in the years following the hurricane found that the indirect death toll was in the thousands. A report commissioned by the Puerto Rico government from George Washington University in collaboration with the University of Puerto Rico narrowed the uncertainty (95% range) to between 2,658 and 3,290, with a central estimate of 2,975. This central estimate was accepted by Puerto Rico as the territory’s official toll for Maria, and NOAA now lists the total U.S. direct and indirect death toll from Maria (including the U.S. Virgin Islands) as 2,981.

Similarly, the direct death toll for Hurricane Katrina of 2005 was 520-822, but a 2007 study that drew on death notices in the New Orleans Times-Picayune estimated that there were 2,358 excess deaths in the local area during the months of January to June 2006, compared to the years 2002-2004.

In developing nations like Malawi and Mozambique, the indirect death toll from a catastrophic cyclone is likely to be much higher than for the U.S. A significant cholera outbreak began affecting Malawi in March 2022. Cases began growing exponentially in January 2023, with 1,500 cholera deaths reported by March 2, making it the deadliest cholera outbreak in the nation’s history. Freddy’s heaviest rains began affecting Malawi on March 11. Cholera surged by a factor of 10 in Mozambique after Freddy’s rains, and 123 cholera deaths have been reported in the country since late 2022.

A list of the deadliest weather disasters in Africa. All of the top 13 were droughts. Five of the top 30 happened in 2022.

In its Disasters Year in Review 2022 report, EM-DAT noted that the human and economic impact of disasters (not including the COVID-19 pandemic) was relatively higher in 2022 in Africa, with 16.4% of the share of all global disaster deaths, compared to 3.8% in the previous two decades. If one includes the 43,000 deaths from the 2022 drought in Sudan, Africa had 65% of all global disaster deaths in 2022. This is a function not only of the unusually high numbers in Africa but also a lower-than-average toll worldwide: The global disaster-related toll of 30,704 in 2022 was only about half of the annual global average from the prior 20 years.

African disaster mortality statistics are highly uncertain

Because of Africa’s poor and vulnerable populations, and the relatively narrow range of variation in Africa’s climate, the continent is expected to suffer among the most severe climate change impacts of any place on Earth. While the large number of deadly African weather disasters in the past year resulted in part from the rare three-year La Niña event in the eastern Pacific, the spate of deadly events could well be a harbinger of the type of dangerous climate impacts that will grow increasingly common for the continents peoples.

However, it is very difficult to detect potential climate change-related trends in African disaster deaths, because these numbers have a high uncertainty. For example, EM-DAT, the international disaster database, lists the death toll of a 2010-11 drought in Somalia at 20,000. However, several other estimates are much higher — a 2023 paper cited references putting the 2010-12 drought toll in Somalia at 256,000. Since drought, war, political instability, and disease all contribute to African famine death tolls, it is a challenging task to separate out the fatalities that can be directly or indirectly attributed to the drought itself. EM-DAT generally requires at least two different sources in order to validate the disaster event and its figures.

In addition, African disaster deaths since 1900 as cataloged by EM-DAT (Figure 2) are dominated by a few mega-disasters, making trend analysis difficult. EM-DAT also omits two disasters with huge death tolls: the estimated 43,000 deaths in Somalia from the 2022 drought and the 44,700 deaths from the 2017-18 drought. EM-DAT states that “it is impossible to draw conclusions about the underlying causes of the century-long trend in disaster mortality based on EM-DAT numbers alone. This is unfortunate because these trends could shed light on the effectiveness of risk management policies and the trajectory humanity is taking toward an uncertain future.” The organization cites a number of problems that increase the uncertainty in determining disaster death toll trends, such as poorer reporting of deaths in the pre-internet age, population growth in areas exposed to disasters, climate change, and global advances in humanitarian aid and disaster-risk management.

A bar chart showing the average annual deaths in Africa from disasters. The year 1980 has the highest total.
Figure 2. Average annual deaths from disasters in Africa, averaged over each decade (data for the decade for the 2020s is from 2020-22). Statistics are taken from EM-DAT, which omits the estimated 43,000 deaths in Somalia from the 2022 drought and the 44,700 deaths from the 2017-18 drought. (Image credit: Our World in Data)

Bob Henson contributed to this post.

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