Today, the river lies a bit further away. Like a green ribbon bordered by fields, it winds its way from the Ethiopian Plateau through the northeastern Sahara to the wide delta in the north. We know, however, that the course of the river was further west at the time the pyramids were built, and the construction site was connected to the river via canals and a harbor.
However, the history of ancient Egypt actually begins much earlier when the Sahara was not yet a desert. About 15,000 to 5,000 years ago, people lived along rivers and lakes in a green Sahara because at that time the climate was much wetter. The Nile Valley, on the other hand, was probably less popular at that time, as it was a rather swampy area and there was a risk of being eaten by crocodiles or at least attacked by thirsty mosquitoes.
For many years, researchers have been exploring the question of how much time people had to leave the increasingly yellow Sahara in the direction of the Nile (and later farther south). Did the climate change abruptly within a few decades or rather gradually, over the course of a thousand years? Another question is whether the Sahara dried up everywhere at the same time or from west to east or north to south.
We investigated this question (and many others) with a drilling project at a dried-up lake near the sources of the Nile on the Ethiopian Plateau. The good news: People had over 1,000 years – the lake did not disappear overnight. The bad news: During this time, the climate became highly unstable, “flickering,” as we say, oscillating dramatically between extreme drought and heavy rainfall before stabilizing at the dry conditions that we see today.
Further to the north, more and more climate refugees from the Sahara crowded into the narrow, green strip of the Nile. We can easily imagine what this climate instability meant for people who were just beginning to settle down and cultivate the first fields. One year there was enough water for farming, and just a few years later, the fields were flooded - or dried out.
However, climate stress may also have provoked the innovative capacity that was necessary for the emergence of one of the most astonishing civilizations in human history, which managed to build the three great pyramids of Giza just 1,000 years after the end of the green Sahara.
This text (in german language) was published in the university magazine Portal - Zwei 2024 „Europa“ (PDF).