As the speed of an object falling toward earth increases, the gravitational potential energy of the object with respect to earth.

As an object falls toward earth, the potential energy of the object: Decreases

In this case, the formula for the Potential energy is:

E = Em + Ek + Eg

Where;

Em is energy due to mass

Ek is kinetic energy

Eg is energy due to gravity

Thus, as the potential energy falls toward earth, Eg will approach 0, which will decrease its amount.

Read more about gravitational potential energy at;