The Guardian has directed its staff to use “climate emergency” or “climate crisis” instead of “climate change” in news stories.

According to an internal email the British newspaper — a proud bastion of liberalism — contends “climate change” sounds “rather passive and gentle when what scientists are talking about is a catastrophe for humanity.”

Rather than “climate skeptic," terms like “climate denier" or “climate science denier” should be used. The email said “global heating” should be used instead of “global warming."

The Associated Press Stylebook, which is the industry standard for most media outlets, states: "To describe those who don’t accept climate science or dispute the world is warming from man-made forces, use climate change doubters or those who reject mainstream climate science. Avoid use of skeptics or deniers."

While stopping short of an outright ban, Guardian editors told staff to "think twice" before including them in stories.

“We want to ensure that we are being scientifically precise in rooted facts, while also communicating clearly with readers on this very important issue,” the email to staff said.

Staff were also instructed to avoid using terms like "biodiversity" and "fish stocks." Instead, "wildlife" and "fish populations" should be used, respectively.

[Also read: Landmark hearing exposes climate change gulf among Republicans and Democrats]