The Himalayas are growing because the Indian tectonic plate is still pushing into the Eurasian plate at roughly 5 centimeters (2 inches) per year, the same collision that created the mountain range in the first place. This process has been underway for about 70 million years, and it shows no signs of stopping. Different parts of the range are rising at different rates, with Mount Everest gaining about 4 millimeters per year and some sections climbing as fast as 10 millimeters annually.
The Collision That Started It All
Around 70 million years ago, during the late Cretaceous period, the Indian landmass began colliding with the Eurasian plate after crossing the remnants of an ancient ocean called the Tethys. India had been part of the southern supercontinent Gondwana and drifted northward over tens of millions of years. When the oceanic crust between the two landmasses was fully consumed, the continental crust of India began sliding beneath Eurasia in a process called subduction.
Continental crust is too buoyant to sink easily into the mantle the way ocean floor does. So instead of one plate diving cleanly beneath the other, the collision crumpled and stacked enormous slabs of rock on top of each other, thickening the crust and pushing it upward. Since the collision began, at least 1,400 kilometers of north-south shortening has been absorbed by the Himalayan-Tibetan region. That’s an extraordinary amount of compression, and it explains both the height of the peaks and the massive thickness of the Tibetan Plateau behind them.
This collision is still active today. India continues creeping northward, and the resulting pressure keeps folding and faulting rock along the boundary. Thrusting is currently active even within relatively young sediment deposits, meaning new faults are forming and old ones are still slipping.
How Fast the Mountains Are Rising
GPS and satellite measurements show the Himalayas are lifting at 5 to 6 millimeters per year across much of the range. Everest specifically grows at about 4 millimeters per year, while other peaks are rising faster, up to 10 millimeters annually. That may sound tiny, but over geological time it adds up. Four millimeters a year translates to 4 meters per thousand years, or 4 kilometers per million years, if nothing were working against it.
In 2020, Nepal and China jointly announced a revised official height for Everest: 8,848.86 meters (29,032 feet), nearly a meter taller than the previously accepted figure. The revision came partly from improved measurement technology and partly because the devastating 2015 earthquake raised questions about whether the peak had shifted. The two countries had also long disagreed about whether to include Everest’s snow cap in the measurement. The new figure resolved that dispute.
Glacial Melting Is Adding a Surprising Boost
Tectonic compression isn’t the only force pushing the Himalayas upward. As glaciers across the range melt and lose mass, the underlying crust is rebounding, similar to how a mattress springs back when you stand up. This process, called glacial isostatic uplift, contributes 0.5 to 2.0 millimeters per year of rise in the Himalayas. That accounts for roughly 10% to 40% of the total observed uplift of 5 to 6 millimeters per year.
Near the largest melting glaciers, this rebound effect can reach 1 to 6 millimeters per year on its own. The effect is significant enough that scientists have had to carefully separate it from tectonic signals in their measurements. In some areas of the broader Tibetan Plateau, glacial rebound has been mistakenly attributed to fault activity, highlighting just how substantial the effect is. As climate change accelerates glacier loss, this rebound component could temporarily increase.
Erosion Takes Back Most of the Growth
The Himalayas would be far taller if uplift were the only force at work. Rain, rivers, glaciers, and freeze-thaw cycles constantly grind the mountains down. Landscape modeling research shows that erosion removes 60% to 70% of the height gained through tectonic uplift. The Himalayas’ own height works against them here: tall mountains intercept moisture-laden air, triggering heavy rainfall on their southern slopes, which in turn powers the rivers that carve deep valleys and carry sediment away.
This means the net growth of the range is only a fraction of the raw uplift rate. If the crust is rising at 5 to 6 millimeters per year but erosion is stripping away 60% to 70% of that, the mountains gain only 1.5 to 2.4 millimeters in actual elevation per year in many locations. The balance between these forces is what determines the ultimate height ceiling for any mountain range. If erosion ever matches or exceeds uplift, the mountains stop growing and begin to shrink.
Earthquakes Can Reshape Peaks in Seconds
The same tectonic forces that build the Himalayas also produce powerful earthquakes, and these can change peak heights almost instantly. Between major quakes, stress builds up along locked faults, gradually bulging the surface upward. When the fault finally ruptures, the sudden release of pressure can actually drop the highest peaks.
The 2015 Nepal earthquake demonstrated this dramatically. Satellite measurements across eastern Nepal showed that the highest peaks dropped by up to 60 centimeters in the first seconds of the quake. The mountains had been slowly gaining height as stress accumulated, and the earthquake reversed that gain in a single moment. Over the following years, stress begins building again and the cycle repeats: slow rise, sudden drop, slow rise. The long-term trend is still upward, but the path is jagged rather than smooth.
Why the Growth Won’t Stop Soon
The Indian plate shows no signs of slowing down. It is still moving northward at 5 centimeters per year, driven by forces deep in the mantle. As long as that motion continues, the crust along the collision zone will keep compressing, folding, and thickening. The Himalayas have been growing for 70 million years, and geologically speaking, the collision is still in full swing.
There is a practical limit, though. As mountains grow taller, the forces tearing them down, gravity, erosion, and their own weight, grow proportionally stronger. At some point, a mountain range reaches an equilibrium where it can’t get meaningfully taller because erosion matches uplift. Whether Everest is near that ceiling or still has room to grow is difficult to say with precision, but the current data show the range is still gaining height faster than it’s losing it. The Himalayas will keep rising for millions of years to come.