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随身英语Loss of biodiversity affects human society 生物多样性减少给人类社会带来影响 Play audio file科学家说动植物种类的减少危急人类生活及环境的健康。本期《随身英语》谈论生物多样性的减少和生态系统的变化。 课文内容 词汇: environment 环境 If a species of bee disappears forever or a particular plant is extinct, what does it have to do with us humans? Well, according to a team of international scientists, biodiversity is dropping below levels considered safe for the wellbeing of human societies. The issue is that everything is interconnected and ecosystems support our societies because they provide us with, for example, food, fibres and fuels. If species go on disappearing, this can interfere with vital processes such as crop pollination and the decomposition of waste. A framework which defines the environmental limits within which humans can operate – called planetary boundaries - says that losing more than 10% of the biodiversity in an area places the local ecosystem at risk. Ecosystems are all different but this percentage is considered a good measure of safety. A study published in the magazine Science suggests that 58% of the world's land surface already falls below this level. These areas house 71% of the global population. Professor Andy Purvis, from Imperial College London and the Natural History Museum, is one of the authors of the study. He says: "Once we're the wrong side of the boundary it doesn't mean everything goes wrong immediately, but there is a markedly higher risk that things will go badly wrong." | 
