Almost a quarter of the world's mammals face extinction within 30 years, a United Nations study on the state of the global environment will announce tomorrow.
Scientists who contributed to the report have identified 11,046 species of plants and animals that are endangered. These include 1,130 mammals – 24 per cent of the total – and 12 per cent, or 1,183 species of birds.
The list of the critically endangered ranges from the well-publicised, such as the black rhino and Siberian tiger, to the less well known, such as the Amur leopard of Asia, the short-tailed chinchilla of South America and the Philippine eagle.
Human activities, notably the destruction of habitats and the introduction of alien species from one part of the world into another, are identified as the main cause of this loss in "biodiversity".
The researchers who helped to prepare the Global Environment Outlook-3 (Geo-3) report of the United Nations Environment Programme (Unep) also identify 5,611 species of plants that are facing extinction. They point out that the true figure is likely to be far higher given that only 4 per cent of the known plant species have been properly evaluated.
The report, which reviews the past 30 years of environmental degradation as well as looking forward to the next 30 years, is understood to say that all the factors that have led to the extinction of species in recent decades continue to operate with "ever- increasing" intensity.
Although Geo-3 covers a wide area of concerns, from the exploitation of land to water pollution, it identifies the need to conserve the Earth's biodiversity as a vital element in the drive towards tackling growing poverty – the theme of this summer's World Summit on Sustainable Development in Johannesburg.
Threats to life on Earth include exploitation of natural resources, pollution, habitat destruction, the introduction of alien species and global climate change, the scientists who advised Unep said. They believe that the loss of habitats by human encroachment is largely responsible for the predicament facing 89 per cent of threatened birds, 83 per cent of threatened mammals and 91 per cent of endangered plants.
Unep has identified alien invasive species as the second major threat, affecting about 30 per cent of threatened birds and 15 per cent of threatened plants.
Geo-3 aims to address the factors contributing to the environmental degradation of the Earth, whether they affect land, air or water. It is expected to say that many problems can be rectified if governments implement the treaties and conventions passed since the Rio Earth Summit of 1992 – including the Kyoto protocol on climate change and the Convention on Biodiversity.
Mark Collins, the director of Unep's World Conservation Monitoring Centre in Cambridge, said: "I think if we are able to knuckle down to carry out the measures that have been proposed since Rio there is cause for optimism."
Nevertheless, the Geo-3 report identifies a number of problems– not least global warming – that appear to be growing. In addition, human poverty is increasing, which is aggravating huge losses in biodiversity and "has to be addressed", Dr Collins said.
Klaus Töpfer, the executive director of Unep, will launch the report in London with Margaret Beckett, the Secretary of State for the Environment, Food and Rural Affairs.
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