* Alpine biomes are fragmented: They occur in mountainous regions across the globe, not in a continuous belt.
* Defining "Alpine" is complex: Some definitions use altitude, others use vegetation, and some consider both.
However, we can make some general estimates:
* High Altitude: Alpine biomes generally occur above the treeline. The treeline varies based on latitude and other factors, but it's generally considered to be around 3,000 meters (9,840 feet) in the tropics and lower at higher latitudes.
* Mountain Ranges: Mountain ranges cover a significant portion of Earth's landmass. Major ranges like the Himalayas, Andes, Alps, and Rocky Mountains all contain alpine regions.
Therefore, while the exact percentage is hard to pin down, it's safe to say that alpine biomes cover a relatively small, but significant portion of Earth's surface.
If you're interested in a more specific estimate, you could look for research papers on the subject, which might provide information on the area covered by alpine biomes in specific regions or mountain ranges.
