A recent scientific assessment has revealed that China’s Three Gorges Dam, the world’s largest hydroelectric power facility, has had a measurable impact on the Earth’s rotation. According to Dr. Benjamin Fong Chao, a geophysicist at NASA’s Goddard Space Flight Center, the structure has slightly lengthened the duration of a day on Earth.
Situated on the Yangtze River in Hubei Province, the Three Gorges Dam was completed in 2012. It spans 2,335 meters in length and rises to a height of 185 meters. The dam holds an immense volume of water—approximately 40 cubic kilometers (equivalent to 10 trillion gallons)—at an elevation of 175 meters above sea level.
This vast quantity of water has subtly shifted the distribution of the Earth’s mass. NASA researchers explain that such a redistribution increases the planet’s moment of inertia, a phenomenon comparable to how a spinning figure skater slows down by extending their arms. This shift causes a slight decrease in the speed of Earth’s rotation.
The impact is extremely small but detectable with modern scientific instruments. Dr. Chao’s analysis indicates that the presence of the dam’s reservoir has extended the length of a day by 0.06 microseconds and altered the Earth’s axis by approximately two centimeters.
Although the change is imperceptible in daily life, it is significant enough to demonstrate how large-scale human infrastructure can influence planetary dynamics.
In addition to its geophysical effects, the Three Gorges Dam remains a cornerstone of China’s renewable energy strategy. With a generating capacity of 22,500 megawatts, it produces electricity equivalent to that of 15 nuclear reactors. The facility contributes substantially to reducing coal dependence and lowering carbon emissions, aligning with broader environmental and energy objectives.
Source: NASA / Analysis by Dr. Benjamin Fong Chao, Goddard Space Flight Center.
