Nikhil
12/3/2025
The Sahara Desert is the world’s largest hot desert, stretching over a staggering 9.2 million square kilometers, nearly the size of the United States. As of today, the Sahara is one of the hottest and driest places on Earth, with temperatures reaching up to 136°F (58°C). It contains sand dunes that reach heights up to 450 meters tall and most of the region receives less than an inch of rainfall annually. Despite these conditions that may seem harsh for life to thrive in, thousands of years ago the Sahara was in fact not a desert as it is today, rather a thriving green land full of lakes, rivers, and life. Learning how the Sahara was once green and how it may return to a green state requires understanding of natural climates cycles and new human-led efforts for restoration.
About 10,000 years ago, Earth’s orbit had a natural shift which changed how sunlight reached different parts of the globe. This phenomenon is a part of the Milankovitch cycles, which caused the northern regions of Africa to receive much more intense sunlight in the summer, resulting in the strengthening of the monsoon rains that reached the Sahara. This once dry region we know today was once full of grasslands, forests, and wetlands abundant with giraffes, hippopotamuses, and crocodiles. Back then, the Sahara had the largest lake in the word, Mega Lake Chad, which was about the size of present day Germany. But around 5,000 years ago, Earth’s orbit shifted again, which led to cooler northern summers and significantly weaker monsoons. This change caused the Sahara to dry out, and by 3000 B.C, it had turned into the vast, inhabitable desert we know today. This pattern of the Earth’s orbit changing and impacting climate patterns has repeated several times, showing how the Sahara’s transformation between dry and green phases is natural should happen again.
Scientists predict that the Sahara will naturally become green again in about 15,000 years and that the actions humans are taking now will speed up that process. The Sahel, which runs along the southern edge of the Sahara, is a dry grassland which stretches from Senegal to Sudan. In 2007, the African Union launched the Great Green Wall Initiative to restore 100 million hectares of degraded land by 2030. The goal is to trap carbon, create new jobs, and restore ecosystems by creating thousands of smaller projects instead of one long stretch of trees in this region. Farmers in African countries around this region used techniques such as mixed planting and rainwater pits to bring the land back to life. As of now, about 20 million hectares have been restored, and even though the progress is slow, recently launched programs and ignited the efforts to reach the goal.
Organizations like Planet Wild are also playing key roles in restoring the “greenness” of regions across the planet. Their projects in regions such as Senegal show that combining science with community action can speed up the natural greening process. As they plant “living fences” and use trees to restore the soil’s fertility, the ecosystems in these areas are coming back much faster than expected. Groups like planet wild create opportunities for people across the world to contribute in the restoration of such areas, helping their environment be rebuilt by communities while simultaneously fighting climate change. Though the Sahara may take thousands of years to return to its previously lush, green state, dedicated global efforts and future innovation can make its rebirth happen much sooner.