Imagine entering a museum of the future. Imagine walking across its great marble floors, dodging the schoolchildren and parents with buggies, past the toilets and the gift shop and down the corridor marked Mammals. Imagine marvelling at the bones and fossil teeth of mammoths, sabre-toothed tigers and giant ground sloths. Now, pause. You are in shadow. You are in the shadow of an enormous towering skeleton of an extinct creature which stands almost 20ft high, with a long neck upon which a horny skull sits, within which would have been a tongue almost as long as a human arm. “On whose watch did such a creature face extinction?” those future museum visitors might ask.

Our watch. For today is the day giraffes first became listed as a threatened species, the day we learned from the International Union for the Conservation of Nature that giraffes are to be listed as “vulnerable” in their international Red List update. The day we learned that their downward spiral had begun. And the day we have to start doing something more to help.

According to the IUCN, giraffe populations have fallen from about 157,000 in 1985 to 97,500 today – a population drop of almost 40%. But the causes of these declines are nothing new: they include the conversion of grasslands to farmland, deforestation and the impact of civil wars, not forgetting the occasional crazed American tourist with a big gun fetish. Giraffes are now split across Africa into discreet populations that no longer mix – they are nine isolated islands of life being increasingly squeezed from all sides.

At this point, it would be tempting to consider their conservation to be an African problem, yet to do so would be a mistake. Mammoths, sabre-tooths and giant ground sloths (all non-African) will have gone through similar such declines – isolated into breeding pockets, which were squashed, one by one, by encroaching threats like climate change, range competition and, in some cases, hunting from early humans. Nine small puddles will evaporate far more quickly than one big puddle, and so it is with life. It is the historic “death-by-a-thousand-cuts”, writ large. Giraffes are just one striking addition to what is fast becoming a global phenomenon. It is the threat of fragmentation.

This year’s IUCN Red List does not only include giraffes; there are a host of creatures threatened by similar fragmentation. They include the African grey parrot and the spectacular sunset lorikeet and the eastern gorilla, as well as (my personal favourite) the geometric tortoise. And fragmentation is a UK issue too. Recent research into common toads offers a striking example of its effects. Isolated by roads and other infrastructure, there is no hope for these charismatic amphibians should their breeding ponds be removed, trashed or left for dead, and so it is that they have faced a two-thirds population decline in the same 30 years that giraffe numbers have dwindled.

But this is a day for us to consider giraffes. Theirs is a story, quite frankly, that few conservationists (including me) saw coming. I am the first to admit that yesterday, before the IUCN update, I had giraffes pegged as beautiful food for lions. Now they, like so many others, have become more; they have become food for thought.

Can we put a good spin on this? Is there anything positive one can say? I believe, yes. For today’s world has something in it that the Pleistocene epoch never had. Today’s world contains perhaps the biggest, most spectacular thing that natural selection is capable of producing: coordinated minds that seek to save things other than themselves – the minds of humans, when we’re at our best.

Perhaps it is through creatures like these that coordinated action can unite the interests of countries over continents

At this very moment, government representatives across the world are gathered at the UN Biodiversity Summit and they will be asked to coordinate actions to save species such as these. They will look at how they can work together, alongside a great number of conservation organisations, to meet the needs of their people and their wildlife. And what could crystallise united action more than a threatened mammalian dinosaur, with long curly eyelashes and an inquisitive innocence that could tug at the heartstrings of even the most cold-hearted?

As sections of societies across Europe and the US appear increasingly to idolise isolationism, perhaps it is through fragmented creatures like these that coordinated action can unite the interests of countries and peoples over whole continents. Maybe, it will be through strange creatures like these that we can show off that which shows the human species at its most special. Future generations that visit museums will be the judge of our success. Or they will instead lament our failure, stood forever in the shadow of our mistakes.