NASA Images Reveal Sahara Desert Turning Green, Scientists Baffled
NASA satellite images have unveiled a surprising transformation in the Sahara Desert, the world’s largest hot desert known for its desolate landscapes. Interestingly, patches of greenery have started to emerge across the desert regions in Morocco, Algeria, Tunisia, and Libya. This unexpected change is attributed to an extratropical cyclone that struck northwestern Africa on September 7 and 8, bringing heavy rainfall – a rare event in an area that typically receives less than eight centimetres of rain annually.
The substantial rainfall has prompted the growth of shrubs and trees in low-lying areas such as riverbeds, leading to areas of greenery within the desert. This phenomenon is not entirely new; scientists have identified more than 230 instances of greening in the Sahara over the past eight million years, occurring approximately every 21,000 years. These greening periods are linked to shifts in the Earth’s tilt, which bring the Northern Hemisphere closer to the sun during the summer, creating a low-pressure system that draws moisture from the Atlantic into the desert.
While the recent rainfall primarily affected sparsely populated regions, it has had devastating effects, with floods claiming over a thousand lives and impacting four million people across 14 African nations. The inundation has caused significant damage to infrastructure, including roads, electricity, and water supplies, as reported by the World Food Programme and the Associated Press. Scientists observed that plant life in northwestern Africa quickly responds to intense rain events, temporarily transforming arid dunes into lush landscapes.
An extratropical cyclone in September, resulting from the unusual movement of the Intertropical Convergence Zone (ITCZ), brought torrential rain to the Sahara. This weather pattern was triggered by the convergence of winds from the Northern and Southern Hemispheres, causing persistent clouds, rain, and thunderstorms due to the interaction of winds, sunlight, and sea temperatures. Unlike the typical heavy rains in equatorial regions like the Democratic Republic of Congo and Uganda, this time the downpours extended to the Sahara.
Scientists are puzzled about the northward shift of the Intertropical Convergence Zone this year, with suggestions that near-record warmth in the North Atlantic Ocean may be a contributing factor. Additionally, global warming disproportionately heating the Northern Hemisphere compared to the Southern Hemisphere could be influencing this unusual weather pattern. The significant increase in greenery is observed in north-central Africa, including regions of Mauritania, Mali, Burkina Faso, Niger, Nigeria, Chad, Sudan, South Sudan, Eritrea, Ethiopia, and Kenya.
Conversely, southern regions such as Guinea, Ghana, central to southern Nigeria, Cameroon, and parts of western Ethiopia have experienced a decline in greenery compared to previous years due to receiving significantly less rainfall than usual. The latest developments in the Sahara highlight the complex interplay of environmental factors impacting one of the world’s most iconic landscapes.