Scientists say that global warming isn't the only serious threat to humans. Another major threat is the falling numbers insects and the extinction many species. Scientists say that half all insects worldwide have been declining the 1970s. A new warning is that 40 per cent insect species could die in our lifetime. Researchers said the number of insects is decreasing 2.5 per cent every year. The scientists are calling it an "insect apocalypse". Many species butterflies, bees and other bugs are now extinct. In the U.K. researchers say 23 bee and wasp species have gone extinct the past century. Scientists say the apocalypse could trigger, "a catastrophic collapse Earth's ecosystems".
Lead researcher Professor Dave Goulson said a lot insects are being killed pesticides used farming and gardening. He said fewer numbers insects might mean we cannot feed people. He told reporters: "Three quarters our crops depend insect pollinators. Crops will begin to fail. We won't have things strawberries. We can't feed 7.5 billion people insects." He said one the most worrying trends is the decline honeybees. In the USA, the number honeybee colonies dropped from six million in 1947 to just 2.5 million in 2014. Professor Goulson warned people that: "We can't wait another 25 years before we do anything because it will be too late."