Long since have I marvelled
How of ten thousand creatures there is not one
But has its tune; how, as each season takes its turn,
A hundred new birds sing, each weather wakes
A hundred insects from their sleep.
Ouyang Xiu (1007-1072) The Cicada
This poem by Ouyang Xiu conveys the essence of biodiversity, though it was written many centuries before the term was used in any language. Yet despite this early conceptual grasp of the earth’s immense variety, 21st century humans still struggle to come to terms with how and why biodiversity matters to us.
A broad definition – “the variety of living forms, their populations, and individual variations in appearance and behaviour” – presents difficulties to scientists asked to quantify biodiversity, who can only guess at the number of tropical rainforest insect species and the ecological roles that each may play. Our knowledge of the oceans and of seabed biology is in its infancy.
Indeed, we can map, remotely, the surface of the moon more accurately than the two-thirds of the earth’s surface that is under water. We know little about crucial linkages between familiar living creatures. In Europe there is uncertainty about the relationship between tuberculosis in wild badgers and domestic cattle; and globally much is unclear about the origins and transmission paths of Avian Influenza (AI).
Despite these uncertainties, there is one globally agreed target relating to biodiversity, endorsed at the 2002 World Summit on Sustainable Development (WSSD): “the achievement by 2010 of a significant reduction in the current rate of loss of biodiversity”.
Like most targets, this represents a huge simplification. Indeed, there can be no single globally quantifiable measure of the current “rate of loss”. Biodiversity is far more than the sum of answers to such questions as: “How much forest cover does the world have?” or “How many species are there?” It is a pulsating network of processes embracing the growth, survival, change – and extinction – of all forms of life on earth. It interacts with other continuously changing processes, like the movement of continental plates, radiation from the sun, the tides and climate.
It often helps to assume the opposite. What if the aim were to reduce biodiversity? How are we doing? Rather well. This is not simply a result of industrialisation. Extensive habitat changes and species loss was already part of the transition to settled agriculture, with the river basin civilizations of China and Mesopotamia well ahead of Europe and the Americas. It is illustrative of this early reduction in biodiversity that the title of Mark Elvin’s environmental history of China is The Retreat of the Elephants. Some of the earliest Chinese writings bear witness to loss of biodiversity:
There was once a time when the trees were luxuriant on Ox Mountain. As it is on the outskirts of a great metropolis, the trees are constantly lopped by axes. Is it any wonder that they are no longer fine?
Mencius (c371-c289 BC)
Nothing, however, compares to the effects of industrialisation, which has provided the tools for far more efficient reduction in the variety of life forms. Plants and wild animals that are economically valuable are often exploited by methods that amount to mining biodiversity: trawlers and chainsaws instead of fishing-rods and axes.
If so many types of biodiversity are being lost, not everybody agrees that this is regrettable. There are three classic approaches.
1) Diverse forms are lost because they have outlived their utility. They are simply not needed.
2) They are lost because their utility has not been recognised. The services provided by living natural resources are more fundamental to our well-being than the material and financial assets of GDP calculations. Biodiversity is needed.
3) Variety is more than a matter of utility. Alpine meadows, coral reefs, trees in city parks and minority languages are all part of the world’s intricacy and beauty which scientists wish to understand, artists and poets to celebrate and everyone to enjoy – for themselves, not because they give us food, shelter or income.
What these different perspectives share, however, is to view life from the standpoint of just one species: Homo sapiens. (Taxonomies based on other forms of life might highlight for humans features other than wisdom. A mosquito or rat, for example, might view humans as respectively “edible” (H. edulis) or as “voyagers” (H. viator)) Now in the 21st century humans are realising how premature is that self-naming claim to wisdom.
This does not easily explain Homo sapiens own very fragmented view of itself as a single species: think of forms of slavery that still exist the treatment of women, minority and immigrant communities in many countries; and the view of many believers that those not sharing their religion are inferior or mired in error. Nevertheless, recognition of shared human identity – that we are one species on earth along with many others – has grown.
Awareness is also growing of the unintended effects that our one species is having on the planet. Loss of biodiversity has been going on for centuries, but awareness of it as a global phenomenon really only developed during the 19th and 20th centuries. Two relatively recent issues – HIV/AIDS and climate change – have made us dramatically aware of our vulnerability.
Today, we have the knowledge to tackle climate change, to clean up rivers, to restore wetlands, to recreate forests – and affect biodiversity positively; but our power to destroy, both deliberately and inadvertently, through our numbers and our activities, appears far greater. It must certainly seem like that from the perspective of other species.
James Lovelock laments in his recent book – The Revenge of Gaia: Why the Earth is Fighting Back –how “The humanist concept of sustainable development and the Christian concept of stewardship are flawed by unconscious hubris. We have neither the knowledge nor the capacity to achieve them. We are no more equipped to be the stewards or developers of the Earth than are goats to be gardeners.” This suggests that to tackle loss of biodiversity and global warming we need to evolve quickly into a new subspecies: Homo sapiens humilis.
Will we learn to reduce our impacts, so that other species have more space? Will Homo sapiens ever become wise enough to realise that for one species to dominate the planet is as unattractive, unstable and unethical as for one nation, class, gender or religion to rule others? Whether human biodiversity targets are ever met will depend on developing a concept of “sharing the earth” in which life forms other than humans are seen not as part of the earth but as part of the sharing.