Northern Africa is among the driest areas in the world, residence to the Sahara desert, the largest hot desert worldwide. This incredibly dry region, where it’s not unusual to have no rain for over a year in some places was when a tropical humid area.
Cave drawings in the Egyptian Sahara portray people swimming in lakes as well as an exotic moist setting. What, then, triggered the complete turnaround of environment from a warm humid as well as wet environment to among the driest areas on Earth? The response hinges on the environment of the Arctic and also northern high latitudes.
Initially, allow’s step back to the time when northern Africa was moist and exotic 5,500 years back. Around 5,500 years ago there was a sudden change in environment in north Africa leading to rapid acidification of the area.
This quick shift 5,500 years ago originates from a cooling of northern high latitudes. The cooler temperatures in the north compromised the high altitude Tropical Easterly Jet, which continually brought moisture right into northern Africa. As a result of the weakening of the Exotic Easterly Jet, the African Easterly Jet strengthened, which indirectly prevents rains in north Africa.
The research team deconstructed this story from leaf waxes, wherein they measured the isotopes of deuterium within the plants to tape-record a proxy for rains in the area. Plants videotape the amount of rains they experience in their cells, altering the isotope proportions of different components depending upon local environment problems. This is a common way geologists reconstruct weather conditions of the past.
What is fascinating is that the air conditioning in the northern latitudes was not all that significant compared to glacial/interglacial cycles that Earth has experienced for thousands of countless years. This suggests mild variations in ordinary temperature level of the northern high latitudes could have a “light switch” impact turning on and also off precipitation in north Africa.
Considering the recent warming of the planet, no place a lot more so than high latitudes, it will certainly be interesting to see if northern Africa at some point flips to a much more tropical and also moist environment. While historical data suggests this is most likely if heating proceeds, the process could take centuries and it’s unclear just how fast that tipping factor is.
While this may look like a net favorable effect of a warming planet, it’s important to realize that there is a finite amount of rainfall around the world. One would anticipate one more area to end up being dramatically drier if one area comes to be substantially wetter. This can imply the introduction of mass movements from areas that progressively have less rainfall to locations that significantly have a lot more rains. Time to buy up land in the Sahara Desert? If you remain in it for the long haul, that may not be a negative concept.