Will a return ever be possible? Will the Sahara turn green again one day?
Even Kröpelin knows that by answering these questions he is delving into the realm of speculation. Nevertheless, he is gathering evidence.
A rare rainfall over the otherwise dry Sudan in 1988 awakened his suspicions for the first time. If everyone was talking about climate change, why shouldn't the monsoon in Africa be changing, too? Perhaps global warming could drive it back to the state it was in once before, after the ice age.
Since that rainstorm in Sudan, Kröpelin has been recording all signs of climate change during his trips, looking for answers to questions like: Where is camel grass growing more abundantly than in previous years? How productive are the few watering holes? And what are the camel herders and date farmers saying?
Of course, all of this is merely anecdotal evidence that doesn't stand up to scientific scrutiny. Nevertheless, Kröpelin is convinced that the evidence is growing. In fact, he says, he even believes that there is now real evidence of change, and that the desert is getting greener.
The geologist feels validated by recent news from the Faya oasis. Last summer, residents told him, they were surprised by a sudden downpour. Huts were washed away and people drowned. This had never happened before, they said.
Translated from the German by Christopher Sultan