Biodiversity is the term given to the variety of life on Earth and the natural pattern it forms. The biodiversity we see today is the result of millions of years of evolution, initially shaped by natural processes, but in modern times increasingly as a result of human intervention.

In late 1993, following the Rio Earth Summit of May the previous year, the UN General Assembly sanctioned International Day for Biological Diversity. Between 1993 and 2000 this took place each year on 29^th December.

In December 2000 it was decided that since so many holidays occur in December, from henceforth the day would be celebrated on 22^nd May to coincide with the date of the Rio Earth Summit in 1992.

Every year there is a different theme for the day. In 2011 the theme was Forest Diversity, while in 2012 it was Marine Diversity. The theme for 2013 is Water Diversity to coincide with the UN International Year of Water Co-operation. The ecosystems of the world ensure that clean water is available to human communities. Water in turn underpins all ecosystem services, so water is key to biodiversity.

We are an integral part of the web of biodiversity and we depend on this web, as does every other life form on the planet.

This diversity of life is usually understood in terms of the world's wide variety of plants, animals and micro-organisms. So far about 1.75 million species have been identified, but scientists think that the true number could be around 13 million.

Biodiversity also includes genetic differences within species, such as differences between varieties of crops or breeds of cattle and even ethnic differences among humans. Chromosomes, genes and DNA are the building blocks of life and together they ensure that every individual of every species is truly unique.

Yet another aspect if biodiversity is its variety. Ecosystems have developed that thrive under certain conditions, such as deserts, forests, wetlands, lakes, rivers and agricultural landscapes. In each of these ecosystems all the living creatures, including humans, form a community where the members interact one with another and with the air, water and soil that surrounds them.

It is this combination of life forms and the way that they interact with each other and with the rest of the environment that has made the Earth a uniquely habitable place for humans. In fact much of what we need to sustain our lives is a result of biodiversity.

It is sobering to reflect that 70% of the world's poorest people live in rural areas, where they depend directly on biodiversity for their survival and well-being.

Protecting the biodiversity of the world is very much in our own interests. The very pillars on which we build civilisations are nothing more than biological resources.

The products of Nature support agriculture, the cosmetic and pharmaceutical industries, the pulp and paper industries, the construction industry and waste treatment. A loss of biodiversity would seriously threaten food supplies and sources of wood, medicines and energy, not to mention opportunities for recreation and tourism.

Unfortunately the abundance of species is declining; with a 40% loss between 1970 and 2000. Unsustainable consumption continues, with worldwide demand for resources outstripping the biological capacity of the Earth by about 20%.

This decline is largely due to human activity and it naturally poses a serious threat to human development. Although there have been mounting efforts over the past 20 years to halt this decline, the loss of the world's biological diversity has continued. The chief reasons are habitat destruction, over-harvesting, pollution and the inappropriate introduction of foreign plants and animals.

It should always be remembered that biological resources constitute a capital asset, with enormous potential for yielding sustainable benefits. If this is not to be lost, urgent and decisive action is needed to conserve and maintain genes, species and ecosystems, with a view to sustainable management and use of these biological resources.