Aridification in Africa 5000 years ago

To start off, what is the term “aridification”? I had no idea when I was looking at environmental articles. Aridification is “the process of a region becoming increasingly dry.” Instead of seasonal variation, this refers to a long-term change in the environment. Many time it is measured by the reduction in soil moisture. Where has this process of drying taken place in the past? The most obvious answer is one of the dryest regions in the world, the central Sahel-Sahara. Researchers happened upon a cave in the Egyptian Sahara and found cave drawings that depicted people swimming. These drawings date back to about 10,000 years ago and fall within the time period, known as the African Humid Period between 11,500 and 5,500 years ago.

Many climate scientists marvel at the fast pace in which the area changed from aridification and other climate processes. Today, a group of researchers has been studying the high-latitude cooling and its role in triggering the rapid termination of the Humid Period. According to the study, the frequency of precipitation was reduced due to the temperature drop in the Arctic as well as the mid-latitudes of the northern hemisphere. With the reduction of precipitation paired with other climate feedback, the scale was tipped towards aridification. These findings are based on the studies performed on an ancient plant leaf wax. The wax was found in the Gulf of Guinea in the sediments. What was discovered was that the wax was made up of long-chain hydrocarbons that are produced by plants to protect themselves from harsh environmental precipitation, like heavy rain for example. This allowed the researchers to conclude there was rainfall in Cameroon and the central Sahara throughout the past millennia.

So what does this mean for us? You could think well that was so long ago, it’s a desert now; why does this matter? Well, the researchers questioned what if the Arctic continues to change in the current state of climate change and came to find that based on the evidence, future Arctic melting, and reduced sea-ice cover may have a strong cause and effect relationship to tropical rainfall. This is just yet another problem that could be caused by the continuation of global climate change.

Science Daily

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