Study warns of impending devastation of insect species by climate change

In a new scientific journal, a team of 70 scientists from 19 countries, including a researcher from the University of Maryland, today warned that if no action is taken to protect insects from climate change, the consequences will “reduce significantly our ability to build a sustainable future based on healthy and functioning ecosystems.

Citing research from around the world, the team painted a grim picture of the short- and long-term effects of climate change on insects, many of which have been in decline for decades. Global warming and extreme weather events are already threatening some insects with extinction, and the situation will only get worse if current trends continue, the scientists said. Some insects will be forced to move to cooler climates to survive, while others will experience impacts on their fertility, life cycle, and interactions with other species.

Such drastic ecosystem disruptions could eventually come back to bite people, explained Anahí Espíndola, assistant professor of entomology and co-author of the paper published in Ecological monographs.

“We have to realize, as humans, that we are one species among millions of species, and there is no reason for us to assume that we are never going to go extinct,” Espíndola said. “These changes in insects can affect our species quite drastically.”

Insects play a central role in ecosystems by recycling nutrients and feeding other organisms further up the food chain, including humans. In addition, much of the world’s food supply depends on pollinators like bees and butterflies, and healthy ecosystems help control the number of pests and disease-carrying insects. These are just some of the ecosystem services that could be compromised by climate change, the team of scientists warned.

Unlike mammals, many insects are ectotherms, meaning they are unable to regulate their own body temperature. Because they are so dependent on external conditions, they may react to climate change more acutely than other animals.

One of the ways insects cope with climate change is by shifting their range or moving permanently to places with lower temperatures. According to a study cited in the article, the ranges of almost half of all insect species will shrink by 50% or more if the planet warms by 3.2°C. If warming is limited to 1.5°C, the goal of the global Paris Agreement on climate change, the ranges of 6% of insects will be affected.

Espíndola, who studies how species respond to environmental changes over time, contributed to the sections of the document that deal with range changes. Drastic shifts in a species’ range can jeopardize its genetic diversity, potentially hampering its ability to adapt and survive, she said.

On the other hand, climate change may make some insects more invasive, to the detriment of human health and agriculture. Global warming is expected to expand the geographic range of some disease vectors such as mosquitoes, as well as crop-eating pests.

“Many pests are actually quite generalist, meaning they are able to feed on many different types of plants,” Espíndola said. “And it’s the insects that, based on the data, seem to be the least negatively affected by climate change.”

The team wrote that the effects of climate change are often compounded by other human-made impacts, such as habitat loss, pollution and the introduction of invasive species. Combined, these stressors make it harder for insects to adapt to changes in their environment.

Although these effects are already being felt by insects, it is not too late to act. The document outlines actions that decision-makers and the public can take to protect insects and their habitats. Scientists have recommended ‘transformative action’ in six areas: phasing out fossil fuels, reducing air pollutants, permanently restoring and protecting ecosystems, promoting predominantly plant-based diets and moving towards a circular economy and stabilizing population global human.

“Insects are tough little creatures, and we should be relieved that there is still room to correct our mistakes,” said lead author Jeffrey Harvey of the Netherlands Institute of Ecology and Vrije Universiteit. Amsterdam, adding that time is running out.

Beyond sweeping societal changes, the paper suggests ways individuals can help, including managing public, private or urban gardens and other green spaces in a more environmentally friendly way – for example, by incorporating plants natives into the mix and avoiding pesticides and major changes in land use where possible. Encouraging family and friends to join is another way people amplify their impact, Espíndola said.

“It’s true that these small actions are very powerful,” she said. “They are even more powerful when not isolated.”