Global warming isn't the only danger to humans. The falling numbers of insects is also dangerous. Half of all insects worldwide have been dying since the 1970s. Over 40 per cent of insect species could die in our lifetime. The number of insects is decreasing by 2.5 per cent a year. It is an "insect apocalypse". Many species of butterflies, bees and other bugs are now extinct. Scientists say this could cause, "a catastrophic collapse of Earth's ecosystems".
Pesticides used on farms and gardens are killing insects. Fewer insects mean we have less food. Three quarters of our crops depend on insects. We can't feed 7.5 billion people without insects. A big worry is the decline of honeybees. In the USA, the number of honeybee groups dropped from six million in 1947 to 2.5 million in 2014. A professor warned that: "We can't wait another 25 years before we do anything because it will be too late."