Large lakes filled with water surrounded by steep sand dunes, reflected in the shadows of green palm trees. This is how the Sahara Desert, specifically southeast of Morocco, one of the driest and most arid places in the world, looked in the latest images taken by NASA satellites late last summer.
Rainfall over desert lands has created newly formed waterscapes across vast areas in the northwest of the Sahara, interspersed with palm trees and shrubby plants. Could the world's largest non-polar desert be transformed into expenses covered in water and greenery?
Heavy summer rains due to climate change
The Saharaa desert usually witnesses an annual fall of only a few inches of rain, but this year heavy rains fell for several days during September in parts of the desert in western east of Morocco after a low pressure system hit the northwest of the desert.
Preliminary data from NASA satellites showed at least eight inches of rain in some parts of the region. The desert city of Elrachidia in southeastern Morocco saw nearly three inches of rain over just two days last month, more than four times the normal rainfall for the entire month of September and more than half the amount of rain that falls in the region in a year, according to CNN.
Lakes that are usually dry, such as the lake in Iriki National Park, Morocco's largest national park, have filled up due to the rain. "It has been between 30 and 50 years since we have seen this much rain in such a short period of time," Hussein Youabed, communications officer for the Moroccan General Directorate of Meteorology, told “The Associated Press”.
These floods swept through parts of the Sahara Desert and some cities and villages in Morocco due to an unusual shift in climate conditions and a flow of rainfall. Scientists warn that these extreme weather events may become increasingly common as the climate crisis accelerates.
Global warming is changing the usual characteristics of rainfall in terms of frequency, intensity and duration, which is changing the characteristics of the usual rainy seasons in many parts of the world, including the Sahara, explained Jung-Eun Chow, an atmospheric and climate scientist at the University of Hong Kong.
The effect of seasonal wind
Rainfall north of the equator in Africa typically increases from July to September with the onset of the West African monsoon season, which is also associated with changes in regional atmospheric circulation. The monsoon phenomenon is characterized by an increase in storms and hurricanes, which occur when moist tropical air coming from the equator meets hot, dry air coming from the northern part of the continent.
These two currents meet in an area known as the Intertropical Convergence Zone, or the Rahul Zone, which is an atmospheric region near the equator, extending around the Earth from east to west. As a result of this meeting of winds, cumulonimbus clouds and heavy rainfall are formed. Therefore, this region, or the Rahul Zone, is responsible for 30% of the world’s rainfall, and is an important driver of energy transfer and oceanic disturbances.
The Intertropical Convergence Zone shifts north of the equator during the summer months in the Northern Hemisphere, while it is mostly south of the equator during the warm months in the Southern Hemisphere.
But climate experts have noticed this summer that the Rahway Range has moved farther north than usual since mid-July, sending storms into the Sahara Desert, including parts of Niger, Chad, Sudan and into North Africa.
As a result, these parts of the Sahara Desert are now two to six times wetter than they should be at this time of year, according to data from the Climate Prediction Center of the US National Oceanic and Atmospheric Administration.
Causes and consequences of storms shifting northward
Some studies link the phenomenon of storms shifting further north than usual to climate change caused by human activities. According to Carsten Hausten, a climate researcher at the University of Leipzig in Germany, this strange shift towards the north is due to global warming, according to his interview with CNN.
Hausten explains that most climate models indicate that the Intertropical Convergence Zone, which is responsible for heavy rainfall and the greening of the Sahara, is moving north as the world warms.
In the same context, a study published in the journal Nature last June concluded that the shift of storms towards the north in this region may occur more frequently in the next two decades, as a result of rising levels of carbon dioxide and global warming due to fossil fuel pollution.
Climate researcher Karsten Hausten added that as global temperatures rise, the climate will be able to retain more moisture, leading to more humid monsoons and more devastating floods like this one.
The northward shift of storms not only greens parts of the arid Sahara, but also disrupts the Atlantic hurricane season, which has had dire consequences in recent months for many African countries, leading to dangerous climate fluctuations.
Countries that were supposed to see significant rainfall have received less because storms have shifted north. For example, areas of Nigeria and Cameroon, which typically get at least 20 to 30 inches of rain from July through September, have received only 50 percent to 80 percent of their normal rainfall since mid-July, according to data from the Climate Prediction Center of the U.S. National Oceanic and Atmospheric Administration.
Conversely, further north, the drier countries, including parts of Niger, Chad, Sudan, Libya and southern Egypt, have received more than 400% of their normal rainfall since mid-July, according to data from the Climate Prediction Center.
These unusual rains have led to the growth of vegetation in the Sahara Desert, the largest hot desert in the world with an area of more than 9 million square kilometers, which is expected to witness more extreme rainfall in the future as fossil fuel pollution continues, the planet warms and the natural water cycle is disrupted.
