As human activities rapidly transform the planet, the global insect population is declining at an unprecedented rate of up to 2% per year. Amid deforestation, pesticide use, artificial light pollution and climate change, these critters are struggling — along with the crops, flowers and other animals that rely on them to survive.
The world has lost 5% to 10% of all insect species in the last 150 years — or between 250,000 and 500,000 species, according to a February 2020 study in the journal Biological Conservation. Those losses are continuing, though estimates vary due to patchy data as well as uncertainty over how many insects exist.
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The demise of insects can’t be attributed to any single cause. Populations are facing simultaneous threats, from habitat loss and industrial farming to climate change. Nitrogen overloading from sewage and fertilizers has turned wetlands into dead zones; artificial light is flooding out nighttime skies; and the growth of urban areas has led to concrete sprawl.
“Nature is just eroding away very slowly,” [Entomologist David] Wagner said. As insects disappear, “we’re losing the limbs and the twigs of the tree of life. We’re tearing it apart. And we’re leaving behind a very simplified and ugly tree.”