The effect of warming on rainfall in Africa

We have all heard about the terrible drought periods that hit the Sahel in the eighties of the last century, the Sahel is that semi-desert strip that is south of the Sahara, in recent years the picture changes from end to end in the geographical meaning of the change

In the south of the continent drought periods are more and more frequent (almost every year), while the arid Sahel is more rainy, unfortunately the rains in the Sahel fall (like in the desert) in cloud fragments and cause floods and floods that are more harmful than beneficial, the inhabitants of the Sahel are not familiar with a strange climate and do not know how to escape from the wadis which turn into gushing rivers, the banks of the wadis near which are located collapsing villages and the vulnerability of property and people is enormous.

So what's going on here?

It turns out that two separate reasons that are not related to each other cause a change. What causes dryness in the Sahel is the cold current flowing in the Atlantic Ocean parallel to the coast of West Africa, the same "Benguela current" that comes from the far south - Antarctica, "attracts" the moisture to it and prevents condensation over the land, prevents rain , this is the cold current that passes close to the coast in Namibia and creates the famous Namib desert, the current moves away from the coast of West Africa and therefore there is a lot of rain and approaches the coast in the north, it affects the dryness in the Sahel and intensifies it in the Sahara like many other factors the Benguela current changes its course cyclically (as yet unknown) and from time to time Approaching the coast, its approach to the coast causes it to warm up and then the dry climate in the Sahel becomes more humid and allows rain.

In addition to this, global warming also causes the Atlantic Ocean to warm (slightly) and thus moderate the effect of the cold Benguela current, but this cycle does not cause the rainy systems that cause floods in recent years, to receive so much rain, another factor is needed and here we are (human activity) Entering the picture, according to measurements, the waters of the Indian Ocean have warmed by one degree in the last fifty years, whether due to the rotation of the earth around the sun (Milankiewicz cycle) or because of the famous and talked about greenhouse effect, it does not matter at the moment what the reason is, the fact exists: the Indian Ocean is warmer, on According to computer simulations that included data from measuring points scattered over the Indian Ocean, it turns out that the warming of the water causes the monsoon winds to be diverted, the ocean water evaporates and condenses into the clouds, the clouds are driven to the continent by the monsoon winds so that the monsoons are actually the rain providers for Africa.

It turns out that as the water warms, the monsoons shift northward, the shift northward leaves Southern Africa without the seasonal rains that its inhabitants are used to and causes a drought, on the other hand, the same shift moves the cloud masses northward, to the dry Sahel
The meeting of clouds saturated with moisture in the relatively cool air coming from the west causes cloud fragments that bring down torrential rain that causes floods above and beyond the familiar, expected and known according to computer simulations, this trend of periods of drought in southern Africa
And high humidity, rains and floods in the Sahel, will increase as the Indian Ocean warms.

Apparently, this system has a direct effect on us: as a regular resident of Eilat, I used to experience southern storms every spring and fall in the bay, storms that would raise high waves that washed the beaches and cleaned the seabed of algae, the storms blew under the influence of the famous "Red Sea depression" The depression does appear from time to time, but There have been no strong storms for about fifteen years.