A new study has found that rising global temperatures could cause the Earth’s insect population to decline by as much as two-thirds by 2100, leading to a “catastrophic collapse of nature’s ecosystems”. Insects play a crucial role in pollination, decomposition and as prey for other species. They are also a key food source for many birds, fish and mammals. The study estimates that by 2100, the planet could lose 18% of beetles, 14% of butterflies and moths, 12% of flies and 19% of ants, bees and wasps. The percentage of “ecologically significant” insects could decline by up to 50% in tropical regions.
The findings argue that the repercussions of this decline could be profound, with knock-on effects on mammals, including humans, and on birds and fish. The researchers recommend that pesticide and habitat protection measures should be implemented now. They also call for a change in farming practices, particularly in the tropics, to prioritise sustainable methods of agriculture.
Commenting on the study, Dave Goulson, professor of biology at the University of Sussex, said: “This study confirms what we’ve been thinking – that the insects are declining to potentially catastrophic levels. We’re having 60% declines in [insect] species over 50 years across the world in terms of abundance. It’s far from just being a problem of bees and butterflies.” He added that: “Huge proportions of the populations of animals that birds and fish rely on are insects. If you wipe out insects, you’re going to wipe out everything else up the chain”.
The study analysed reports in the media and scientific journals of insect declines over the past several decades, and examined out the potential impacts of continuing global emissions of greenhouse gases. On Monday, another report found that the world’s complete vertebrate population – mammals, birds, reptiles, fish and amphibians – had halved in just 40 years.
The study’s lead author, Prof. Brad Lister, from Rensselaer Polytechnic Institute in New York, described the findings as “hyper-alarming”. “If we don’t stop the decline of our insects there will be profound consequences for all life on Earth”, he warned. The study has been published in the journal Biological Conservation.
