Living urban lives in our towns and cities, it is easy to be cut off from the natural world and not register the cataclysm which is overtaking it.
The World Wide Fund for Nature estimates a third of the world's wildlife has disappeared since 1970.
Yet all over the globe, as Andrew Balmford shows in his gripping new documentary-cum-study Wild Hope - concerned men and women are trying to hold back the tide of ruination, and sometimes succeeding.
Balmford, Professor of Conservation Science at Cambridge, travelled to every continent save Antarctica, in search of examples where conservation on the ground is actually making a difference. The seven detailed case studies all show that with committed people and imaginative policies the widespread destruction of nature can be halted and reversed.
In some cases it ultimately means shooting armed poachers to protect India's remaining one-horned rhinos in Assam.
The species is a target for poachers because of the value of their horns in traditional Asian medicine.
But in other situations vividly portrayed in Wild Hope, such as the attempts to preserve South Africa's unique fynbos flora, or the cloud forests of Ecuador, the trick is to make other players - governments, businesses or communities - understand that preservation can be in their interests too.
Balmford is an astute analyst of why it works in some places and not in others. There is no doubt Wild Hope will be taken by conservation professionals and students as a textbook.
But underlying the technical insights is the larger question of whether or not the obliteration of the natural world can be held back generally.
As Balmford admits: "The sad reality is that the majority of conservation efforts are not so successful and most activities that diminish nature...evoke no organised response at all."
Yet the very fact that these conservationists are doing what they are, throws the issue into sharp relief.