How is biodiversity — the vast variety of plants and animals on earth — useful?

• At a recent, unique conference organised by the Pontifical Academy of Sciences at the Vatican involving nature and social scientists, the focus was on the slender thread by which 90% of humanity’s food security hangs — which is, just 103 varieties of plants that are regularly cultivated. At the same time, there is detailed knowledge of only a fifth of all estimated plant species that exist. Yet, vast areas of earth are being deforested before the rest can even be studied. A similar lack of full understanding of how plants, animals and the environment interact, with consequences for humans, underscores the need for restraint, scientists say.

What is the threat to the world’s biodiversity?

• The real possibility that half of all wildlife will disappear permanently by the turn of the century worries scientists, who say human beings have not taken into account the irreplaceable services like water, food, medicines, flood control and pollution abatement that nature provides them. This is in contrast to other types of accepted accounting, such as determining poverty lines, direct environmental losses and climate change impact. As the planet’s population continues to grow, and resource consumption rises, the rate of species loss is accelerating.
• Major threats to biodiversity are clearing of land for agriculture and urbanisation, spread of alien species, pests, and disease-causing organisms, unsustainable hunting and gathering of animals, and climate change. As scientist Paul R. Ehrlich describes it, a single species is determining the fate of all others.

But have there not been past extinctions?

• There have been five mass extinctions so far in Earth’s geological history, with a more than 75% loss of estimated species. The earliest, the Ordovician, about 440 million years ago, was followed by the Devonian (365 million years), Permian (245 million), Triassic (210 million), Cretaceous (65 million). What differentiates the current fate of plants and animals from those is the relentless human pressure on nature.

What can be done?

• Conservationists like Prof. Ehrlich, who view a surging population coupled with consumption as the primary threat, advocate more women’s education to reduce the birth rate. Sustainable practices like cutting fossil fuel use, accounting for the value of ecological systems, sparing wild areas from resource extraction, expanding urban agriculture, and preserving species in sanctuaries are ways forward.

Source: The Hindu