Earth is cultivable soil. The earth in the fields about 300 meters from our house consists primarily of sand and clay and is of high quality. We tend to take good soil (earth) for granted.
Or we think that contamination of the earth is a relatively recent phenomenon caused by major disasters like the radioactive fallout from Chernobyl in 1986.
You would be surprised that there is contamination in Germany not so far from where we live (about 30 minutes) due to mining during the Middle Ages over 500 years ago.
Contamination can be forever and as the singer Prince says "that's a mighty long time". 500 years ago, in the process of separating silver and other minerals from the rock, the soil became permanently contaminated with arsenic, lead, cadmium and thallium (among other things). There's nothing anyone can do to reverse the damage.
Now imagine you want to build a new house and you're looking at this pretty green meadow with a great view.
In the region around the town of Wiesloch, in the earth there are highly concentrated amounts of heavy metals which you cannot see, smell or identify in any way. As a home builder, you are responsible for the removal of the earth which is escavated for the foundation. There are high fees for this because the earth is classified as "hazdarous" and requires a special closed transport to a special facility.
You also will never be able to grow vegetables directly in the soil in your garden but instead would need to purchase soil and grow everything in planters. You wouldn't want your small (grand) children crawling around putting dirt in their mouths either...
Now think about all of the damage we are doing to the environment today. It will also be forever. Our earth is precious, let's preserve it.