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| The validity of this article as a news story is, as written, disputed. Wikinews does not publish reports on events that are not sufficiently recent. For synthesis, new details must have come to light within the past two or three days, and the news event itself must have happened within a week. Unless sources can be found and a news event chosen to bring this article into compliance with those requirements, the article may be deleted.
If any new details from the last two to three days are newsworthy in their own right then an article could be written with these updates as the actual news event. Exceptions are possible where original reporting adds significant new and newsworthy information to the article.
Please try to resolve objections on the discussion page, or move the article to Wikipedia or another sister project where it may be more relevant. |
Monday, October 1, 2018
A newly published scientific study suggests the most recent transformation of the Sahara into a desert, about 5500 years ago, was not accelerated by human over-use of the land and may instead have been delayed as much as 500 years by human land-use practices. The study, by scientists at University College London (UCL) and King’s College London, was published in Nature Communications on Monday.
The Sahara region, occupying most of northern Africa, alternates between green periods and desert periods due to precession of the Earth’s orbit. Past scientific work has suggested the onset of the current desert period may have happened sooner because of human over-use of the land. The current study used a new model of climate and vegetation, including evidence of greenhouse gases in ice cores, to estimate when the desert onset ought to have occurred in the absence of human intervention, and archaeological evidence of human population in the Sahara over time.
The study used increments of 500 years for their climate timeline, judging this degree of precision was available from their methods. According to their timeline, humans hunting-gathering and fishing populated the Sahara about 10.5 thousand years ago (kya), and humans herded cattle, sheep, and goats in the region from about 7.0 kya, with a human population boom in the region after 7.0 kya. The study showed the climate conditions were especially sensitive to potential collapse into desert from 7.0 to 6.0 kya, but the collapse, as evidenced by a crash of human population, didn’t occur until 5.5 kya. The scientists concluded this was inconsistent with humans accelerating the onset of desert, and suggestive that human interaction with the environment delayed the onset. Lead author Chris Brierley, of UCL, noted, “Our study shows that increasing human population and sustainable pastoralism did not accelerate — and may even have delayed — the decline of the ‘Green Sahara’?”.