Why setting ‘safe’ limits for environmental damage won’t work

The boundaries set for human impacts on the planet are deeply flawed and only encourage us to keep pushing towards them, warns Stuart Pimm

It is such a seductive idea at a time when environmental worries seem to be multiplying rapidly. So long as we keep the impacts of human activity within set limits we can carry on as we are without jeopardising the ability of Earth’s ecosystems to recover.

Breaching these “planetary boundaries”, goes the argument, takes us to tipping points – rapid and irreversible transitions to a world much less favourable to human existence. This school of thought combines the whiff of some serious mathematics – catastrophe theory – with folksy wisdom that says “we’re safe, so long as we don’t cross the line”.

Alas, this is deeply flawed for several reasons. With more and more predictions of environmental doom and use of the boundaries idea to guide us, my colleagues and I felt the need to raise the alarm (Trends in Ecology and Evolution