The climate crisis is set to profoundly alter the world around us. Humans will not be the only species to suffer from the calamity. Huge waves of die-offs will be triggered across the animal kingdom as coral reefs turn ghostly white and tropical rainforests collapse. For a period, some researchers suspected that insects may be less affected, or at least more adaptable, than mammals, birds and other groups of creatures. With their large, elastic populations and their defiance of previous mass extinction events, surely insects will do better than most in the teeth of the climate emergency?
Sadly not. At 3.2C of warming, which many scientists still fear the world will get close to by the end of this century (although a flurry of promises at Cop26 have brought the expected temperature increase down to 2.4C), half of all insect species will lose more than half of their current habitable range. This is about double the proportion of vertebrates and higher even than for plants, which lack wings or legs to quickly relocate themselves. This huge contraction in livable space is being heaped on to the existing woes faced by insects from habitat loss and pesticide use. “The insects that are still hanging in there are going to get hit by climate change as well,” says Rachel Warren, a biologist at the University of East Anglia, who in 2018 published research into what combinations of temperature, rainfall and other climatic conditions each species can tolerate.
Some insects, such as dragonflies, are nimble enough to cope with the creeping change. Unfortunately, most are not. Butterflies and moths are also often quite mobile, but in different stages of their life cycle they rely on certain terrestrial conditions and particular plant foods, and so many are still vulnerable. Pollinators such as bees and flies can generally move only short distances, exacerbating an emerging food security crisis where farmers will struggle to grow certain foods not just due to a lack of pollination but because, beyond an increase of 3C or so, vast swaths of land simply becomes unsuitable for many crops. The area available to grow abundant coffee and chocolate, for example, is expected to shrivel as tropical regions surge to temperatures unseen in human history. [Continue reading…]