Morality As a Limit
Environmentalism is the ethical system that holds nature to be the standard of value. Nature, in this sense, means that which is not a result of the actions of man. Nature is what would be left if mankind never existed. It is often described as "the environment".
Environmentalism is potentially the most evil ethical system ever devised. It holds that any action man takes is evil. Since man needs to act in order to live, environmentalism condemns him to death. Any action man takes to further his life is "destruction of the environment". The standard of good, nature, means the only moral action man can take is the destruction of mankind. Even altruism allows people to live, if they constantly sacrifice for others. Environmentalism holds no reason for humans to live at all.
As with most evil ethical systems, environmentalism is rarely practiced consistently. Many environmentalist won't see that their ethical system is rooted in wholesale slaughter of human life. They think that their beliefs are compatible with human life. But this is due to their inconsistency. Their willingness to compromise on occasion. Human life can continue if it doesn't get in the way too much, they say. The degree to which they heed this ethical system is the degree to which they promote the death of mankind.
See the following online article:
Environmentalism: Don't Judge It by Its Extremists by Patrick Stephens.