* Defining a "mountain" is subjective: There's no universally agreed-upon definition of what constitutes a mountain. Some definitions use a minimum elevation gain, others use the shape of the landform.
* Varying definitions lead to varying results: Depending on the definition used, the percentage of land covered by mountains will change.
* Data limitations: Even with a defined criteria, accurately measuring the area covered by mountains globally is a complex task.
However, here are some general estimations:
* Roughly 24% of the Earth's land surface is covered by mountains. This is based on various studies and classifications that define mountains as having an elevation of 2,000 feet or more.
* Other estimations range from 10-30%, depending on the definition and data used.
It's important to remember that these are just estimates. There is no definitive answer to the question of what percentage of the Earth's surface is covered by mountains.
