Will mankind ruin the earth being repair, will God let this happen?

Mankind can ruin the Earth, but not beyond repair. The Earth does have an ecology of its own with powerful strategies of reparation, where mankind can be included or even partly or totally excluded. When mankind has destroyed many things about it and so all mankind, the Earth will have other life to fill its surface its soil its air.

Our own God can have a more resolute purpose than the God of somebody else or of others. We can even say that God can destroy mankind through the unwise actions (war etc.) of mankind.

Mankind does have a staunch wish to survive, therefore mankind will seek to repair the damages done to the Earth and to mankind. If the bright heads and the bright powers of mankind will succeed in harmonizing and promoting a good ecology of the Earth, mankind on Earth can survive and thrive in beautiful sun-kissed landscapes with wonderful dreamy horizons.

Or the Earth will make its own ecology to prevail, to reestablish an order that the Earth knows about. I will say that the Earth does have a wondrous or weird life of its own. Of course the Earth is in interaction with the cosmos about it in a configuration of what we call universe with its own ecology that we do not know much about, not yet, perhaps never at our present level of evolution.

We can try and repair the beauty and health of the Earth in our surroundings. We do have a tendency for beautiful things. If we can tame our greed and promote our wisdom, we can make and preserve our surroundings and the Earth beautiful and healthy so it will be health-corroborating for ourselves and for all the other life that we do care about.