Is the 'insect apocalypse' real, or hype?

The honest answer is: real in many places, but its global size is not known. That is how the 2019 global assessment by the Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services (IPBES) put it: global trends in insect populations are not known, but rapid declines have been well documented in some places, sometimes even without large-scale land-use change. The press went further, with headlines such as "Insect Apocalypse", and in 2017 ecologist Dave Goulson said we are on course for "ecological Armageddon".

The declines are real. Besides the Krefeld traps, the Rothamsted suction-trap survey found that insect biomass fell by over two-thirds in southern Scotland between 1970 and 2002, and European studies have documented declines in some butterflies, moths, bees and beetles. A 2020 meta-analysis of 166 long-term studies estimated that land insects are declining about 9% per decade.

But the declines are far from uniform. In some localities overall insect populations have increased, and some types of insects appear to be increasing across the world. The same Rothamsted survey found biomass stable in England, and the same meta-analysis found freshwater insects increasing by 11% per decade. And nearly all studies of regional insect trends come from Europe and the United States, which hold less than 20% of the world's insect species.

That is why some scientists pushed back on the most dramatic forecasts. In March 2019 the Entomological Society of America said there was not yet enough data to predict an imminent mass extinction, and that some extrapolations might be "over-hyped". The same year Chris Thomas and colleagues wrote that accounts of the demise of insects "may be slightly exaggerated", while calling for joined-up action on insect declines backed by better data. Even the estimates of risk differ: IPBES gave a tentative 10% of insect species threatened with extinction, while a 2022 survey of 629 invertebrate experts averaged around 30%.