The great Sahara is one of planet Earth’s most prominent land features. This mega desert sprawls across almost the entire of North Africa, and we have known for years that it helps to cool and temper much of the world’s climate. Yet, we also know that climate change is slowly eroding this African giant, turning its dusty plains greener, and one day it could lead to a catastrophic climate tipping point as the Sahara ceases to cool the planet. Sadly, recent research has shown that this looming threat could be even more destructive than we thought, as they have found yet another way the Sahara has been helping to keep climate change at bay.
Okay, so that is rather a lot to unpack, so let’s start at the beginning. What is a climate tipping point? A climate tipping point is a critical threshold that, when crossed, leads to extensive and often irreversible changes in the climate system. For example, permafrost melting. The Arctic permafrost contains billions upon billions of tons of frozen carbon dioxide and methane. At a certain level of global warming, these frozen stores will thaw and suddenly release insane levels of carbon emissions, causing unimaginably destructive dramatic and sudden climate change.
The Sahara has its own tipping point. You see, it helps cool the planet (which I will get onto in a second), but as the planet warms, it could disappear. This is because a warmer climate will accelerate the water cycle around the Sahara, shifting the African monsoons northwards and transforming the desert into a verdant green wonderland. We know this because it has happened before, during the African Humid Period 11,000 to 5,000 years ago. Back then, natural oscillations in the Earth’s orbit around the Sun slightly warmed the Earth’s climate, causing the Sahara to turn into a vast grassland.
So as we heat the planet up, the Sahara should turn green again. We are already seeing this, as satellite images have shown the desert has been getting greener year-on-year for over 15 years. As the dust desert reduces, so too does its cooling effect, accelerating its demise until eventually, the Sahara is no more, and our climate…
