Mount Everest, the world’s most famous peak, is still growing. This ongoing change is not a sudden event, but the result of vast, slow-motion geological forces active for millions of years. Its height is a dynamic measurement, constantly being altered by the deep pressures of the Earth and the opposing forces of nature. The mountain’s current elevation is a snapshot of continuous geological processes.
The Driving Force: Himalayan Tectonics
The reason for Mount Everest’s steady growth lies in the power of plate tectonics, specifically the collision between two continental landmasses. Approximately 50 million years ago, the northward-moving Indo-Australian Plate began to crash into the Eurasian Plate, an event that continues today. Because both plates are composed of relatively light, buoyant continental crust, neither plate can easily subduct, or sink, beneath the other.
Instead of one plate sliding cleanly underneath, the crust in the collision zone is compressed, folded, and thrust upward, a process known as crustal shortening. This continuous compression formed the vast Himalayan mountain range, including Everest, and actively pushes the peaks higher. The Indian Plate still moves into the Eurasian Plate at a rate of a few centimeters each year, translating into relentless pressure on the mountain system.
The mountain’s stability is also supported by isostasy, which describes the buoyant equilibrium of the Earth’s crust. Continental crust floats on the denser mantle below, much like an iceberg floats in water. The weight of Everest is supported by a deep, low-density “root” of crust extending into the mantle. As tectonic forces push the mountain up and thicken this crustal root, the mountain rises to maintain this buoyant balance.
Quantifying the Uplift: Rate and Measurement
The current, internationally agreed-upon height of the mountain, jointly announced by Nepal and China in 2020, is 8848.86 meters above sea level. This measurement reflects a modern consensus and incorporates advanced techniques that allow scientists to track the mountain’s subtle upward movement.
The rate of uplift is measured using highly precise geodetic techniques, such as Global Navigation Satellite Systems (GNSS). By placing GNSS receivers on and around the mountain, scientists track minute changes in the mountain’s three-dimensional position over time. Traditional surveying methods, like triangulation, are also used, but they are combined with satellite data for verification and greater accuracy.
On average, Everest is thought to be growing at a rate of several millimeters per year, with recent GPS data suggesting a rate of about two millimeters annually in some areas. Measurement challenges include determining whether to include the snow and ice cap, which varies in depth, and compensating for local gravitational anomalies. Furthermore, a recent study suggests that isostatic rebound caused by the erosion of nearby river gorges contributes to this uplift, effectively making the mountain lighter and causing it to float higher.
Limits to Growth: Erosion and Seismic Adjustment
While tectonic forces provide the upward push, the mountain’s height is constantly challenged by powerful opposing forces, primarily erosion. The extreme weather conditions at Everest’s altitude, including high winds, ice, and constant freeze-thaw cycles, relentlessly wear away the rock surface. This weathering breaks down the mountain’s material, which is then carried away by gravity, avalanches, and the intense flow of water into river systems like the Ganges and Brahmaputra.
Major seismic events also play a role in what is known as seismic adjustment. Earthquakes, which are common in this tectonically active region, can cause sudden, localized changes in elevation. For instance, the massive 2015 Nepal earthquake raised questions about whether the peak had shrunk due to a compacting or slumping effect.
Ultimately, Mount Everest’s current height represents a dynamic equilibrium. The rate of tectonic and isostatic uplift is roughly balanced by the loss of material due to erosion and occasional seismic shifts. This balance between constructive and destructive forces means the mountain is a perpetually changing geological feature.