Only in ‘dark skies’, away from the bright lights of Australian cities, can we see the Milky Way arcing across the sky, humanity’s most fundamental connection to the cosmos. Our artificial light also masks day length and other cues used by animals to regulate their daily activity and annual reproduction. Under the relentless glare of urban light pollution, behaviours change and instincts falter.

Online abuse and bearing witness to the destruction of what many of us know (and love) intimately can take a heavy toll on scientists and environmental advocates. But the choices we make now will determine the future we inherit. Far from feeling that all is lost, Euan Ritchie urges all to speak and act for the voiceless, to care for and defend what you love.