The Stewardship of Creation

While reading about energy and sustainability this weekend, I briefly considered one Christian response -

Sins against environment are serious because they harm the common good and are counter to reason in other ways, but
even these sins pale in comparison to the explicit rejection of God? Even though these sins may involve great injustice and cause the suffering of many, they can still be forgiven -- Christians must keep this perspective even if they share the same concern as non-Christian environmentalists, who may be inclined toward fatalism or misanthropy, particularly when they make prognostications and talk about solutions (such as population reduction). (With the supposed affinity between Pope Francis and Ecumenical Patriarch Bartholomew in mind... I think they do give a proper Christian understanding of the stewardship of creation.)