Scientists say that global isn't the only serious to humans. Another threat is the falling numbers of insects and the of many species. Scientists say that half of all insects worldwide have been declining since the 1970s. A new is that over 40 per cent of insect species could die out in our lifetime. Researchers said the of insects is decreasing by 2.5 per cent every year. The scientists are calling it an "insect apocalypse". Many species of butterflies, bees and other are now extinct. In the U.K. researchers say 23 bee and wasp have gone extinct in the past century. Scientists say the could trigger, "a catastrophic of Earth's ecosystems".
Lead Professor Dave Goulson said a lot of are being killed by pesticides used for farming and gardening. He said fewer of insects might mean we cannot feed people. He told reporters: "Three of our crops depend on insect pollinators. Crops will begin to fail. We won't have things like . We can't feed 7.5 people without insects." He said one of the most trends is the decline of honeybees. In the USA, the of honeybee colonies dropped from six million in 1947 to just 2.5 million in 2014. Professor Goulson warned people that: "We can't wait 25 years before we do anything because it will be too ."