‘Biodiversity’ is a rather lifeless word to describe the wondrous diversity of life on Earth. The myriad species with which we share this planet enrich our lives not only economically but aesthetically and spiritually. Our grandchildren’s lives will be poorer if they grow up in a world without polar bears, blue whales, condors and mahogany trees.

Yet these species are endangered, along with thousands of others. Indeed, up to a third of all species could be lost within the next 50-100 years, mainly as a result of human activity. The causes range from deforestation and urbanisation to pollution, hunting, over-fishing, pesticide use and the construction of hydroelectric dams. Global warming will compound the problem because it is likely to disrupt – and in some cases obliterate – entire ecosystems.

To prevent extinction, it isn’t enough to keep animals in zoos or genetic material in laboratory freezers – although that may be necessary as a last resort. What’s needed is to protect entire habitats to ensure the long-term viability of species. This alone is sufficient argument for protecting the Earth’s remaining natural areas.

See also Energy and climate, Forests, Oceans.