Warmer climate leads to current trends of social unrest and mass migration: study
Research by an international team of scientists led by University of New Mexico Professor Yemane Asmerom suggests contraction of the Intertropical Convergence Zone (ITCZ) during a warming Earth, leading in turn to drying of the Neotropics, including Central America, and aggravating current trends of social unrest and mass migration.
Positioned near the equator where the trade winds of the northern and southern hemisphere converge, the ITCZ is the world's most important rainfall belt affecting the livelihood of billions of people around the globe. Globally, seasonal shifts in the location of the ITCZ across the equator dictate the initiation and duration of the tropical rainy season. The behavior of the ITCZ in response to the warming of the Earth is of vital scientific and societal interest.
"What we found was that in fact during the Medieval Climate Anomaly
Southern Belize was very dry, similar to modern central Mexico. In
contrast, during the Little Ice Age cool period, when it should have
been dry by the standard old model, it was the wettest interval over the
last 2000 years," said Asmerom. "The pattern that emerges when all the
data across the full transect of ITCZ excursion is supportive of the
expansion-contraction model." The implication of this that regions
currently in the margins of the ITCZ are likely to experience aridity
with increased warming, consistent with modeling data from Central
America. These data have important implications for rainfall-dependent
agriculture system on which millions of people depend for food security.
"This work highlights the convergence of good science with policy relevancy. It also illustrates the strength of cross-disciplinary collaborative work, in this case international," said Asmerom.