The approximate amount of elevation change between the highest and lowest points on Earth's surface is approximately 20,000 meters (65,600 feet).

Here's the breakdown:

* Highest point: Mount Everest, at approximately 8,848 meters (29,031 feet) above sea level.

* Lowest point: The Challenger Deep in the Mariana Trench, at approximately 10,924 meters (35,840 feet) below sea level.

Therefore, the total elevation change is approximately 8,848 meters + 10,924 meters = 19,772 meters (64,872 feet). This is close to the approximate figure of 20,000 meters.