A single blue whale, even with a skeleton of 4.5 tonnes, weighs imperceptibly in the world’s scales when biological annihilation is set on the other side. Yet perhaps the “new” 126-year-old star of the entrance hall of Natural History Museum in London may play some tiny part in tipping the balance. By replacing “Dippy” – the much-loved cast of a diplodocus skeleton – with a creature whose relatives still swim the oceans, the museum seeks to remind us of the glories that remain in the natural world, and the urgent need to conserve them.

The whale was unveiled as the Guardian revealed that researchers believe a sixth mass extinction is under way (marginally more optimistic scientists think we are merely on the verge of such an event). Estimating overall populations – not just the number of exterminated species – they conclude that up to 50% of all land animals have been lost in recent decades. Unlike the Cretaceous-Tertiary extinction, which saw off Dippy et al, this one is manmade. Scientists blame human over-population and consumption and expect the challenges to intensify, “painting a dismal picture of the future of life, including human life”. We are not just threatening the creatures with whom we share the world; we are risking our own future. Admittedly, other new research assures us that life on Earth is secure even in the event of cosmic calamity. But while the endurance of the portly micro-animals known as tardigrades may console those thinking on such a grand scale, most of us would rather these creatures have company – including ours.

Can disaster be averted? Humans hunted blue whales to the brink of extinction but, thanks to the international ban, the population has recovered from hundreds to around 20,000. It is a fraction of the previous level, but the start of a viable population: enough for the museum’s specimen to be named Hope. Though few of the species under threat are as charismatic as whales, they are as precious. At present, conservation efforts are nation- or creature-specific. A far more ambitious approach is needed: ultimately, a Paris-style accord for biodiversity going beyond the current trade-focused Cites agreement. First must come a recognition of how pressing the dangers are. Where there’s Hope, may there be life.