The historic drought hitting the Greater Horn of Africa is the unprecedented conjunction of a lack of rain and high temperatures that could not have occurred without the consequences of human emissions of greenhouse gases, shows a scientific study published Thursday, April 27.

"Climate change caused by human activities has made agricultural drought in the Horn of Africa about 100 times more likely" than in the past, the World Weather Attribution (WWA), a global network of scientists that immediately assesses the link between extreme weather events and climate change, said in a report.

Since the end of 2020, the countries of the Greater Horn of Africa (Ethiopia, Eritrea, Somalia, Djibouti, Kenya and Sudan), a large peninsula in the east of the continent, have been experiencing their worst drought in forty years.

Five rainy seasons in a row have killed millions of livestock and destroyed crops. According to the UN, 22 million people are at risk of hunger in Ethiopia, Kenya and Somalia (where an Islamist insurgency is also rife).

According to the 19 scientists who contributed to the report, climate change has had "little effect on the recent annual rainfall" of the region. But it has strongly influenced rising temperatures, responsible for a skyrocketing increase in evapotranspiration that has led to record drying of soils and plants.

"It was climate change that made this drought so severe and exceptional," Joyce Kimoutai, a Kenyan climate scientist contributing to the report, said in a telephone briefing on Wednesday.

Five rainy seasons in deficit

The WWA network, founded by renowned climatologists, has established itself in recent years for its ability to assess the influence, more or less strong and unsystematic, between extreme weather events – heat waves, floods, drought, etc. – and human-caused climate change.

Its results, produced urgently, are published without going through the lengthy process of peer-reviewed journals, but combine peer-reviewed methods, primarily with historical weather data and climate models.

This time, WWA focused its study on three of the most affected countries (southern Ethiopia and Somalia and eastern Kenya).

He found that climate change was changing the two rainy seasons in opposite ways: the heaviest one, between March and May, "becomes drier and the rainfall deficit is twice as likely" as in the past, while "the short season becomes wetter".

But in recent years, "this wet trend of the short season has been masked by the climate-cyclical phenomenon of La Niña" which reduces tropical rainfall and which there is no evidence to date that it is influenced by anthropogenic climate change.

This rare conjunction, in a region that has been experiencing five rainy seasons in deficit since the end of 2020, then combined with rising temperatures to lead to record drying of soils and plants.

If the planet had not already warmed by 1.2 degrees compared to the pre-industrial era, this rainfall would have subjected the region to conditions, at worst, "abnormally dry", a level below the first degree of severity of drought in the American classification, assures the WWA.

Clearly, "climate change was a necessary condition for such a severe drought to occur," the scientists conclude.

The current situation is described as an "exceptional drought", the 4th and last alert level on the American scale. Once unlikely, it now has a 5% chance of reproducing each year.

With AFP

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