Sahara Desert has expanded by 10% since 1920

New research recently published in the Journal of Climate suggests that human-caused climate change and natural climate cycles have caused the world's largest, warm-weather desert to expand since the early 20th century.

The Sahara Desert. Image credit Wikipedia.
<img src="https://vortex.accuweather.com/adc2004/pub/includes/columns/climatewx/2018/590x330_04041659_1024px-sahara_satellite_hires.jpg"/>

The study, which was conducted by the University of Maryland and funded by the National Science Foundation, is the first to assess century scale changes to the boundaries of the world's largest desert.

The research team determined that natural climate cycles accounted for two-thirds of the expansion and the remaining third was likely caused by man-made climate change.

The largest expansion of the Sahara desert occurred in summer, with a 16 percent increase in area compared to the summers back in the early 20th century.

The Sahara, like other deserts across the world, tends to expand during the dry winters and contract during the wetter summers.

<strong>What may be the specific causes of this long-term expansion?</strong>

Key excerpt from the <a href="https://www.nsf.gov/news/news_summ.jsp?cntn_id=244804&org=NSF&from=news" target=n>National Science Foundation report.</a>

<em>"Deserts usually form in the subtropics because of what's called Hadley circulation, through which air rises at the equator and descends in the subtropics," said Sumant Nigam, who is an atmospheric and ocean scientist at the University of Maryland and senior author of the study. That circulation has a drying effect. "Climate change is likely to widen this Hadley circulation, causing the northward advance of subtropical deserts," said Nigam. "The southward creep of the Sahara suggests that additional mechanisms are at work."</em>