How climate change is turning the Sahara green

For climatologists, the Sahara is an open-air museum of nature. Weathering and wind bring up ancient landscapes. Many areas were frequently covered by huge lakes and large sandstone mountains developed in the basins. The single sediment layers are like age rings telling a story of humid and dry periods.

The desert as an immense data bank, as climate changes and their effects on civilization can be traced more than hundreds of thousands of years. Geologists, biologists and collected data leave no doubt that there have always been extreme climate changes within quite a short time. The Sahara had once been a fertile grassland, even fossilized trees have been discovered by explorers. Scientists formerly assumed that the Sahara had been transformed into a fertile land by the ice ages; today, we know, that a warm period with tropical rains had revived the desert. Although meteorologists keep warning not to project the climate changes of the past exactly onto the future, they come to the conclusion, however, that the global climate warming can regionally have very different effects.

In order to establish a forecast, interactions between the oceans, the atmosphere, ice masses and soil surface have to be considered in the climate models. How the climate is going to influence the Sahara in future cannot be said for sure. However, the desert has shown a greener image over the last 15 years. Increasing temperatures lead to a stronger evaporation over the sea; said condensations rain down onto dry land. Especially in summer, heavier rainfalls occur in the central Sahara. As reported, there are also torrents, which have supposedly put the dry valleys four meters under water. This is a blessing for the desert as the vegetation recovers.

Sahara acts as a paradox of climate change. But who knows if the green desert will also be the winner of climate warming in the long run? This has yet to be found out.