A moment of global agreement

Biological diversity (or biodiversity) means the variety of living things. It is a term that passed from conservation science into international law through the Convention on Biological Diversity (CBD). This was agreed at a UN conference in Rio in 1992, along with the conventions on climate change and desertification, and entered into legal force on 29 December 1993. Those were the heady days when peoples, experts and governments could agree on the need for urgent action to save nature and the human future. But in the years that followed goals and targets were repeatedly missed, and our global problems kept on getting worse.

A subtle but important idea

Meanwhile the word ‘biodiversity’ never really caught on as a way to promote public understanding. To make it make sense it often had to be translated into stories and pictures about endangered animals, plants and nature reserves. This gave the impression that biodiversity just meant ‘wildlife’. But it is in fact a different, deeper and more subtle idea about the nature of all living systems, which are involved in crises of global heating and climate change, desertification and water stress, and poverty and insecurity. So it’s worth going back to the very beginning to see what ‘biodiversity’ really means.

Immortal life

All living things (or organisms) share a common and continuous ancestry from the start of life on Earth nearly four billion years ago. Life as a whole is thus effectively immortal, even though all individual organisms eventually die. But if they have been able to cope in their own particular environment, they will have reproduced before dying. If so, then their offspring will keep their lineage going for another generation. Uncountable lineages since the beginning have thus struggled to continue, all competing to seed every new instant and environment with their own kind of life.

Diverse life

Under this pressure, the lineages of life spawned a near-infinity of different forms. Each made a living in its own way, and bred almost true until opportunity or necessity changed the rules of its existence. Then new forms arose by natural selection, time after time, rising and falling into extinction as changing environments dictated. All this creativity and intergenerational memory was made possible by complex molecules that stored, copied and passed on the information needed to make each organism in each place and time. These molecules are what we call genes and genetic material, the stuff of heredity and design information in living systems.

The Tree of Life

Now consider the myriad trillions of individual organisms and tens of millions of distinct lineages (or species) at any moment of Earth’s history, all living in intricate relationships with one another. Then you see the complexity and diversity of life on Earth, which we call biodiversity. Add the perspective of billions of years, with each species only lasting a short while before being replaced, and you have the immortal Tree of Life itself. This is a metaphor for something well beyond ordinary human understanding. A Tree rooted in the unimaginably distant past, bearing a shimmering, ever-changing canopy of life forms on the twigs and branches of its many tangled lineages

The Living World

And now add the curved surface of the Earth, oceans and atmosphere within which the Tree grows: the great planetary ecosystem that we call the living world or Biosphere. This unites all the subsystems and environments inhabited by every organism and species that lives on the planet today. These two visions of the Tree of Life and the Biosphere are useful and important, and should be taught from birth in all societies (as they are in some). The idea of the Tree tells us how we as organisms came into being, and that of the Biosphere tells us where and how we live as organisms among many others. The idea of biodiversity is integral to both.

Our divided minds

These concepts help to place us in the Universe. They also give us a context and reason for our existence, both as organisms and as conscious, social beings able to make informed and debated choices. These two aspects of being human are equally true. We have an animal existence shaped by heredity and evolutionary change, as well as individual consciousness shaped by culture and life-experience. But tensions within this double truth yield dilemmas, as well as enormous potential for cooperation and selfishness, which we often call good and evil.

Careless economics

People have recently gained access to fossil energy in the form of coal and petroleum, and combined its use with powerful new technologies. Thus we have built an economic system that has been allowed to operate almost regardless of the rules of ecological sustainability. Dire and dangerous consequences are now rampant: global heating from pollution that traps the Sun’s heat in the Biosphere; ecosystem degradation from over-exploitation and the expansion of settlements, infrastructure, plantations and farmlands; and mass extinction of non-human life forms from direct harm to natural ecosystems and from climate change.

The shedding of leaves

By these means we have blighted the Tree of Life, which is now shedding ‘leaves’ (species), ‘twigs’ (genera) and ‘branches’ (larger and deeper lineages) faster than at any time since the meteor strike that killed the non-avian dinosaurs 65 million years ago. And it is doing so much faster than at any other time in Earth’s history. This loss of biodiversity is rapidly degrading the integrity of the living systems that we depend upon. The blight is also undermining the stability of the oceans, Amazon, Arctic and other major Earth systems. The consequences if they tip into chaos are scarcely imaginable, but on present trends it could happen in this very century. Thus the blight threatens to end our comfort and prosperity, and quite possibly our existence.

A day to remind us …

Which brings us to the International Day for Biological Diversity. This was declared by the United Nations in 1994 to mark the CBD’s coming into force on 29 December. But in 2001 the date was changed to 22 May to avoid the distractions of mid-winter and year-end festivals. Its purpose is to remind us of the need to respect the Tree of Life and the Biosphere, of what we have been doing to them with our careless economic system, and of how we must regulate our behaviour to stay within the bounds of sustainability. In short, of the need to restore harmony with nature before everything tips into chaos.

And a day for celebration and commitment

In 2023, the International Day for Biological Diversity is a reminder of acute danger. But it can also allow for celebration that we are starting to recognise the threat, and to act on it. Many now remember that nature is the most valuable thing we have. We are living more gently within nature, and voting for better and greener governments. Our great task now is to restore ecosystems and peace with nature, and on this day we should think realistically about how to do so. In practice it can mean donating to wildlife trusts and community rewilding initiatives, or participating in actions to protect nature, or helping to build a sense of ecological reality among young and old. All such efforts are welcome, and all are vital for the Tree of Life and Biosphere.

© Julian Caldecott