what is some evidence that the earth is suffering?

From the text:

To the red country and part of the gray country of Oklahoma, the last rains came gently, and they did not cut the scarred earth.

The surface of the earth crusted, a thin hard crust, and as the sky became pale, so the earth became pale, pink in the red country and white in the gray country.

The air was thin and the sky more pale; and every day the earth paled.

Behind the tractor rolled the shining disks, cutting the earth with blades not plowing but surgery, pushing the cut earth to the right where the second row of disks cut it and pushed it to the left; slicing blades shining, polished by the cut earth.