A groundbreaking study conducted by geologists from Ben-Gurion University of the Negev has revealed crucial insights into how climate fluctuations over the past 230,000 years have influenced the migration of drainage divides in Israel’s Negev Desert. Published in Proceedings of the National Academy of Sciences (PNAS), the research provides the first-ever time-dependent record of drainage divide migration rates, offering a unique perspective on how climate shifts shape the Earth’s surface.
Drainage divides are topographic boundaries that separate neighboring drainage basins—areas where water from rainfall or melting snow flows into a single outlet, such as a river or lake. The migration of these divides can have significant effects on the surrounding landscape, including the redistribution of water, rock particles, and even ecological niches. While previous studies have examined long-term average rates of divide migration, this new research reveals more detailed, time-sensitive data on the process.
The research team, led by Prof. Liran Goren, along with Elhanan Harel and collaborators from the University of Pittsburgh and the Geological Survey of Israel, focused on a unique field site in the Negev Desert. They studied a sequence of terraces, which allowed them to trace the movement of drainage divides across thousands of years.
Linking Divide Migration to Climate Change
One of the most exciting aspects of this study is the discovery that episodes of rapid drainage divide migration correlate with periods of climate change in the region. The researchers found that during certain climatic fluctuations, the migration rate of divides doubled compared to other periods. This finding sheds light on how climate changes over millennia influence the physical dynamics of the Earth’s surface.
“It’s an exciting discovery,” said Prof. Goren, whose team used field observations, river terrace dating, and numerical simulations to construct the migration timeline. “We were not expecting to discover the correlation with climate fluctuations nor the speed with which the divide shifted. It adds to our knowledge of the drivers affecting the Earth’s surface evolution in fascinating ways.”
The Negev Desert, often seen as a barren landscape, has now proven to be a key site for understanding climate’s influence on natural processes. While the area may seem unremarkable at first glance, it holds valuable clues about how the Earth has evolved over time. Elhanan Harel, a PhD student involved in the research, expressed awe at how this small desert channel could tell such a powerful story about divide migration and climate history.
“We discovered that even this modest site can provide a remarkable record of drainage divide migration,” Harel said. “This discovery will contribute to the ongoing scientific conversation about the climatic history of the Negev and offer a new way to think about the dynamics of our planet’s surface.”
The study not only enhances our understanding of landscape evolution in arid regions but also opens up new avenues for examining the relationship between climate and the Earth’s topography. As the researchers continue to explore the Negev Desert’s secrets, the findings are likely to inform future studies on the broader impact of climate change on ecosystems and natural landscapes worldwide.
The research was supported by the United States–Israel Binational Science Foundation (BSF) and the U.S. National Science Foundation (NSF-Geomorphology and Land-use Dynamics).
