Sahel: Growing concern over impact of climate change on the Sahel

The Sahel region (; from ساحل (sāḥil ) 'coast, shore'), or Sahelian acacia savanna, is a region in . It is the between the more humid to its south and the drier to the north. The Sahel has a and stretches across the of between the and the . Although geographically located in the tropics, the Sahel does not have a .

Especially in the western Sahel, there are shortages of food and water due to its very high and the . This is exacerbated by very high across the region, resulting in a rapid increase in population. In recent times, various , , and have taken place in many Sahel countries, especially across former .

The Sahel spans 5,900 km (3,670 mi) from the in the west to the in the east, in a belt several hundred to a thousand kilometers (c. 600 miles) wide. It covers an area of 3,053,200 square kilometers (1,178,850 sq mi).

Representing a climatic and ecological with , the Sahel region borders the to its south and the desert to the north. This is also called the Sahelian in honour of its most prominent and very drought tolerant genus of tree.

The topography of the Sahel is mainly flat; most of the region lies between 200 and 400 meters (660 and 1,310 ft) in elevation. Several isolated plateaus and mountain ranges rise from the Sahel (e.g. , , ), but are designated as separate ecoregions because their flora and fauna are distinct from the surrounding lowlands (e.g. ). Annual rainfall varies from around 100–200 mm (4–8 in) in the north of the Sahel to around 700–1,000 mm (28–39 in) in the south.

The Sahel is mostly covered in grassland and savanna, with areas of woodland and shrubland. Grass cover is fairly continuous across the region, dominated by annual grass species such as , and . Species of are the dominant trees, with the most common, along with and . Other tree species include , , , , , , , , , , , , , , , , , , , , and . In the northern part of the Sahel, areas of desert shrub, including and , alternate with areas of grassland and savanna. During the long dry season, many trees lose their leaves and the predominantly annual grasses die.

The Sahel was formerly home to large populations of grazing mammals, including the (Oryx dammah), (Gazella dama), (Gazella dorcas), (Gazella rufifrons), the giant prehistoric buffalo (), and (Alcelaphus buselaphus buselaphus), along with large predators, such as the (Lycaon pictus), the (Acinonyx jubatus hecki), the (Acinonyx jubatus soemmeringii), and the (Panthera leo). The larger species have been greatly reduced in number by over-hunting and competition with livestock, and several species are (Dorcas gazelle, cheetah, lion and red-fronted gazelle), ( and ), or (the Scimitar-horned oryx is probably , and both and the Bubal hartebeest are now extinct).

The seasonal wetlands of the Sahel are important for moving within Africa and on the .

The Sahel has a ( BSh). The climate is typically hot, sunny, dry and somewhat windy all year long. The Sahel's climate is similar to, but less extreme than, the climate of the located just to the north.

The Sahel mainly receives a low to very low amount of precipitation annually. The steppe has a very long, prevailing dry season and a short rainy season. The precipitation is also extremely irregular, and varies considerably from season to season. Most of the rain usually falls during four to six months in the middle of the year, while the other months may remain absolutely dry. The interior of the Sahel region generally receives between 200 mm and 700 mm of rain yearly. A system of subdivisions often adopted for the Sahelian climate based on annual rainfall is as follows: the Saharan-Sahelian climate, with mean annual precipitation between around 100 and 200 mm (such as , Sudan), the strict Sahelian climate, with mean annual precipitation between around 200 and 700 mm (such as , Niger) and the Sahelian-Sudanese climate, with mean annual precipitation between around 700 and 900 mm (such as , Burkina Faso). The in the steppe is low to very low, often between 10% and 25% during the dry season and between 25% and 75% during the rainy season. The least humid places have a relative humidity under 35%.^[]

The Sahel is characterized by constant, intense heat, with an unvarying temperature. The Sahel rarely experiences cold temperatures. During the hottest period, the average high temperatures are generally between 36 and 42 °C (97 and 108 °F) (and even more in the hottest regions), often for more than three months, while the average low temperatures are around 25 to 31 °C (77 to 88 °F). During the "coldest period", the average high temperatures are between 27 and 33 °C (81 and 91 °F) and the average low temperatures are between 15 and 21 °C (59 and 70 °F). Everywhere in the Sahel, the average mean temperature is over 18 °C (64 °F).

The Sahel has a high to very high year-round, between 2,400 hours (about 55% of the daylight hours) and 3,600 hours (more than 80% of the daylight hours). The sunshine duration in the Sahel approaches desert levels, and is comparable to that in the , for example, even though the Sahel is only a steppe and not a desert. The is low to very low. For example, , Niger has 3,082 hours of bright sunshine; , Mali has near 3,385 hours of sunshine; , Mali has 3,409 sunny hours, and , Chad has 3,205 hours of sunlight.

For hundreds of years, the Sahel region has experienced frequent droughts and . One megadrought lasted from 1450 to 1700, 250 years. There was a major drought in the Sahel in 1914 caused by annual rains far below average, leading to large-scale famine. From 1951 to 2004, the Sahel experienced some of the most consistent and severe droughts in Africa. The 1960s saw a large increase in rainfall in the region, making the northern drier region more accessible. There was a push, supported by governments, for people to move northwards. When the long drought period from 1968 through 1974 began, grazing quickly became unsustainable and large-scale denuding of the terrain followed. Like the drought in 1914, this led to a large-scale famine, but this time somewhat tempered by international visibility and an outpouring of aid. This catastrophe led to the founding of the .

Between June and August 2010, famine struck the Sahel. Niger's crops failed to mature in the heat, 350,000 faced starvation, and 1,200,000 were at risk of famine. In Chad the temperature reached 47.6 °C (117.7 °F) on 22 June in , breaking a record set in 1961 at the same location. Niger tied its highest temperature record set in 1998, also on 22 June, at 47.1 °C in . That record was broken the next day, when Bilma hit 48.2 °C (118.8 °F). The hottest temperature recorded in Sudan was reached on 25 June, at 49.6 °C (121.3 °F) in , breaking a record set in 1987. Niger reported on 14 July that , starvation, , and had sickened or killed many children. The new appealed for international food aid and took serious steps to call on overseas help. On 26 July, the heat reached near-record levels over Chad and Niger, and in northern Niger about 20 people reportedly died of dehydration by 27 July.^[]

The Sahel region faces environmental issues that are contributing to . If the change in climate in the Sahel region "is not slowed-down and possibly reversed through sustainable practices and any form of , it is only a matter of time before countries like Niger lose their entire landmass to desert due to unchecked unsustainable human practices. , over-grazing, of marginal lands, and natural , have caused serious of the region. This has affected shelter construction, making it necessary to change the used materials. The Woodless Construction project was introduced in Sahel in 1980 by the Development Workshop, achieving since then a high social impact in the region. A major initiative to combat desertification in the Sahel region via reforestation and other interventions is the .

Major are a frequent occurrence as well. During November 2004, a number of major dust storms hit , originating in the . This is a common area for dust storms, occurring on average on 100 days every year.

On 23 March 2010, a major sandstorm hit Mauritania, Senegal, , , , and inland . Another struck in southern , inland Mauritania, Mali and northern at the same time.

Following the drought period of the 1970s and 1980, however, the Sahel began to experience increased rainfall. This may be due to , which can cause changes that may result in changes in large-scale weather patterns, such as increased stronger monsoons, in turn caused by a warmer Atlantic Ocean. Warming of the may also be a factor.

Protected areas in the Sahel include in Senegal, in Burkina Faso, in Mali, in Niger, and in Cameroon.

Traditionally, most of the people in the Sahel have been semi-, farming and raising livestock in a system of . The difference between the dry north with higher levels of soil nutrients and the wetter south with more vegetation is exploited by having the herds graze on high-quality feed in the north during the wet season, and trek several hundred kilometers to the south to graze on more abundant, but less nutritious, feed during the dry period.^[]

In Western Sahel, and are common. is also practiced across the Sahel.

The term "Sahel" is borrowed from the name for the region, الساحل al-sāḥil. Sāḥil literally means "coast, shore", which has been explained as a figurative reference to the southern edge of the vast Sahara. However, such use is unattested in , and it has been suggested that the word may originally have been derived from the Arabic word سهل sahl "plain" instead.

Around 4000 BC, the climate of the Sahara and the Sahel started to become drier at an exceedingly fast pace. This climate change caused lakes and rivers to shrink significantly and caused increasing . This, in turn, decreased the amount of land conducive to settlements and caused migrations of farming communities to the more humid climate of .

The Sahelian kingdoms were a series of monarchies centered in the Sahel between the 9th and 18th centuries. The wealth of the states, like the legendary at the time of , came from controlling the routes across the desert, especially with the . Their power came from having large like camels and horses that were fast enough to keep a large empire under central control and were also useful in battle. All of these empires were quite decentralized with member cities having a great deal of autonomy.^[]

The larger emerged from 750 AD and erected several large cities in the region, including , and .

Due to the to their south, the Sahelian states were hindered from expanding into the north Akan state of the and , as mounted warriors were all but useless in the forests. In addition, the horses and camels were susceptible to the humidity and diseases of the tropics.

The Western Sahel fell to in the late 19th century as part of . was added in 1900 as part of . The French territories in the Sahel were in 1960.

The Sahel's easternmost region did not fall to the European powers but to the when it was by in the 1820s. By 1899 it came under until at in 1956.

According to , in recent years the Sahel has become the epicenter of , contributing to 35% of all global deaths from terrorism by 2021, with , an al-Qaeda-affiliated group, identified as the world's fastest-growing terrorist organization. In 2023, fatalities from conflict in the central Sahel rose by 38%, according to data from the research organization Armed Conflict Location and Event Data Project.

In the wake of the beginning in 2011, terrorist organizations operating in the Sahel, including , and (AQIM), have greatly exacerbated the violence, extremism and instability of the region. In March 2020, the United States sent a special envoy for the Sahel region to combat the rising violence from groups. The Catholic charity has highlighted the fact that the Sahel has become one of the most dangerous regions in the world for Christians.

As of 2024, a wave of new military juntas in Africa, favoring Russian mercenaries over Western forces and UN peacekeepers, has intensified violence. This led Mauritania and Chad to disband the , an anti-terrorism alliance, after the military regimes in Burkina Faso, Niger, and Mali withdrew.

According to the , the Sahel region has become the global epicenter of terrorism, accounting for over half of all terrorism-related deaths, according to the (GTI). In 2023, the region recorded 3,885 fatalities out of a global total of 7,555, marking a nearly tenfold increase since 2019. The surge in extremist violence is attributed to the expansion of groups like the Islamic State's affiliate in the Sahel and Jama'at Nusrat al-Islam wal Muslimeen (JNIM), who compete for land and influence while imposing strict Sharia-based governance. Political instability, weak governance, and the rise of military juntas following coups in , Burkina Faso, , and have further fueled the insurgency. These groups sustain their operations through ransom kidnappings, illicit gold mining, and drug trafficking, with the Sahel now a major route for cocaine smuggling from South America to Europe. Meanwhile, governments in the region have shifted their alliances from Western nations to Russia and China, relying on paramilitary groups like the Africa Corps (formerly Wagner) for security assistance, though with limited success. The violence is increasingly spilling into neighboring countries such as Togo and Benin, raising concerns about the broader destabilization of West Africa.

On 9 July 2020, the raised concerns over growing number of allegations of and abuses by state security forces in Sahel. The US response came after released documents regarding the same on 1 July. Reports in March 2022 show militants are expanding and spreading out south of the Sahel.

The area has also seen , with currently ruling in Mali, Burkina Faso, Niger, Chad, and Sudan.

The violent , , and other countries in the Sahel region have been exacerbated by , , and rapid . Droughts and food shortages have been also linked to the .

The Sahel is experiencing more severe weather due to climate change, exemplified by the extreme heatwave of March-April 2024 in and . This event was intensified by a 1.2°C global temperature increase from human activities.

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