Research links Southeast Asia megadrought to drying in Africa [mid-Holocene]

EurekAlert! ^ | August 21, 2020 | University of Pennsylvania

[SunkenCiv]

Physical evidence found in caves in Laos helps tell a story about a connection between the end of the Green Sahara, when once heavily vegetated Northern Africa became a hyper-arid landscape, and a previously unknown megadrought that crippled Southeast Asia 4,000 to 5,000 years ago.

In a paper published in Nature Communications, scientists at the University of California, Irvine, University of Pennsylvania, William Paterson University of New Jersey, and other international institutions explain how this major climate transformation led to a shift in human settlement patterns in Southeast Asia, which is now inhabited by more than 600 million people...

To create a paleoclimate record for the study, Johnson and other researchers gathered stalagmite samples from caves in Northern Laos. In her UCI laboratory, they measured the geochemical properties of the oxygen and carbon isotopes, carbon-14, and trace metals found in the specimens. This helped them verify the occurrence of the drought and extrapolate its impacts on the region...

The modeling experiments suggested that reduced plant growth in the Sahara led to increased airborne dust that acted to cool the Indian Ocean and shift the Walker circulation pattern eastward, causing it to behave in ways similar to modern-day El Niño events. This, ultimately, led to a large reduction in monsoon moisture across Southeast Asia that lasted more than 1,000 years, according to Johnson.

Anthropologists and archaeologists have previously studied the effects of the demise of the Green Sahara, also known as the African humid period, on population centers closer to Western Asia and North Africa, noting the collapse of the Akkadian Empire of Mesopotamia, the de-urbanization of the Indus Civilization (near present-day Pakistan and India) and the spread of pastoralism along the Nile River.

[SunkenCiv]

Ooh, that was an oldie! Thanks for the kind remarks.