The shrinking of lakes due to climate change isn’t just about disappearing water sources; it can have dramatic, even explosive, consequences for the Earth’s crust. This connection is starkly illustrated by Lake Turkana in East Africa, a body of water often dubbed “the cradle of humanity” due to its trove of ancient hominin fossils.
Lake Turkana, the world’s largest desert lake nestled within Kenya and Ethiopia’s Great Rift Valley, has seen dramatic fluctuations in size over millennia. Around 9,000 years ago, it was considerably larger, surrounded by lush grasslands and forests, a far cry from its present-day arid landscape.
As the climate shifted drier between 4,000 and 6,000 years ago, Lake Turkana’s water levels plummeted by a staggering 100 to 150 meters. This seemingly gradual reduction in water mass had profound implications for the lakebed below, creating less pressure on its underlying geological faults.
This is where climate change intersects with seismic and volcanic activity. Research led by Christopher Scholz at Syracuse University has revealed that as the lake dried, the edges of these faults began to slip past each other more rapidly. This increased slippage, averaging 0.17 millimeters per year, translates into heightened earthquake potential. “Essentially, the drying system allows for easier slipping along this fault zone,” explains Scholz.
The reduced water weight also likely facilitated volcanic eruptions. Computer models suggest it allowed magma trapped below the lakebed to rise more easily toward the surface. This finding is significant because it builds upon previous research linking lower sea levels with increased volcanism at ocean ridges, now offering concrete evidence of the same phenomenon occurring around a freshwater lake.
Lake Turkana already boasts three volcanic islands, one of which erupted in 1888. While increasing rainfall linked to climate change is gradually replenishing Lake Turkana’s water levels, it will take thousands of years for these changes to noticeably dampen seismic and volcanic activity.
This research highlights a crucial point for risk assessments: climate change isn’t just about rising sea levels or extreme weather; it can profoundly impact geological processes like earthquakes and volcanic eruptions. Governments must factor in the potential consequences of fluctuating water levels, particularly before constructing or removing dams, by integrating earthquake monitoring into infrastructure projects within at-risk regions.
