Habitat loss, climate change, pollution, over-exploitation and the spread of invasive species all remain huge threats that will require extraordinary efforts to tackle. But time has not yet run out.
The UN's ambitious new Sustainable Development Goals include a target to halt biodiversity loss by 2030.
An article in The Lancet even dismissed the SDGs as nothing more than "fairy tales". So is halting biodiversity loss a fairy tale?
'Biodiversity' refers to the diversity of life on Earth. It includes diversity within species, between species, and of ecosystems. There are any number of statistics that confirm its decline across the globe.
For instance, the Red List of threatened species, developed by the International Union for the Conservation of Nature (IUCN), identifies 22,784 that are at risk of extinction - almost 30% of the species that have been assessed. By other measures, habitats continue to be destroyed and degraded, and population sizes of most wild species are in decline.
This is bad news not only for nature lovers but for all of us since we rely on biodiversity to deliver many crucial services such as pollinating crops and providing medicines.
Reasons to be hopeful
By projecting current trends forward in time, a study published in Science last year concluded we are already on course to miss most of the international community's other main targets for biodiversity - the 'Aichi Targets' - which were adopted in 2010 under the Convention on Biological Diversity (CBD) and aspire to improve things by 2020.
So why might the new SDG biodiversity target be any more achievable than those that have gone before? The inclination is to be extremely pessimistic, but there are some reasons to be hopeful.
The same Science paper also looked at indicators of societal responses to the biodiversity crisis. Here the trends are much more in the right direction. Coverage of protected areas is increasing across the planet, sustainable management practices in industries such as fishing and forestry are taking root, and public awareness of biodiversity issues is rising.
There has been real progress in the policy arena. To date 184 of 196 parties to the CBD have developed National Biodiversity Strategies and Action Plans, which set out actions such as promoting laws and providing funds to help achieve the convention's goals.
The establishment in 2012 of the Intergovernmental science-policy Platform on Biodiversity and Ecosystem Services (IPBES) also provides an important new mechanism to inject sound scientific advice into policy making.
In business as well, biodiversity conservation and the related concept of 'natural capital' are becoming mainstream. For instance, the Natural Capital Coalition is developing the economic case for valuing natural ecosystems and includes buy-in from some of the biggest players in business, accountancy and consulting.
And the financial industry is moving toward more responsible investing. The UN Principles for Responsible Investment, which commit investors to act in accordance with conventions such as the CBD, now has almost 1,400 signatories who manage assets with a combined total of US$59 trillion.
These are major positive changes that have come to the fore in the past decade or so. And there are conservation success stories that illustrate how such changes can turn things around for biodiversity.
For example, the latest update to the IUCN Red List reports that conservation action has bolstered populations of the Iberian lynx, which had only 52 mature individuals in 2002. And the Guadalupe fur seal, which had twice in the past been thought to have gone extinct due to hunting, is also making a comeback.
More generally, there is an overall positive trend among populations of almost 1,000 bird and mammal species across much of the northern hemisphere.
Time has not run out - yet
These instances of good news still leave us a long way from halting global biodiversity loss. I don't mean for a moment to underestimate the magnitude of the problem. Habitat loss, climate change, pollution, overexploitation and the spread of invasive species all remain huge threats that will require extraordinary efforts to tackle.
But time has not yet run out. Although many plants and animals are threatened with extinction, we have in fact lost only a few percent of known species over recent centuries. It is heartening that there is still an astonishing amount left to save.
It will take time to slow and turn around the juggernaut that is biodiversity loss, and everyone must pull in the same direction in order to shift course. The period over which the new SDGs will run, from now until 2030, will be absolutely crucial for making this happen.
There are indications that things are beginning to turn around. Hints that we can do this. It would be a big mistake to dismiss the biodiversity target as a fairy tale.
And anyway, fairy tales usually have happy endings, don't they?
Richard Pearson is Reader of Biodiversity at UCL.