How will a hotter climate affect insects?

Over the past 50 years insect populations have dramatically decreased, is climate change responsible?
24 August 2021



Nancy got in touch to ask, "With the new IPCC report saying temperatures are going to rise by at least 1.5 degrees, how is that going to affect insects? Is climate change the biggest driver of insect loss?


Dave Goulson, from the University of Sussex, author of Silent Eart: Averting the Insect Apocolypse. Dave helps Nancy break down the facts... 

Dave - Yeah, that's an interesting question. Not overall, probably not going to be great news for them, as you might guess. There'll be some insects that probably enjoy it. The kind of pesty insects like house flies and mosquitoes. They can breed fast. They're adaptable. They have big populations and they will probably just thrive. But sadly, the majority of the species that we would want to keep will do less well, some will just not like the warmer weather. So my favourites, the bumblebees they're big furry creatures adapted to cold climates and they simply overheat in warm weather. And they're already starting to shift away from the warmer parts of their ranges. You might think a lot of other insects like butterflies might benefit from warmer weather, but the evidence is that they're not. And it's probably because historically their ranges will have tended to shift towards the poles as it got warmer in previous climatic warming events. But now they're existing in very fragmented habitat. So they can't just gently move northwards because they've got to cross huge expanses of hostile habitat; farmland, motorways housing estates to get to the next little fragment of good habitat. So yeah, it's just one more stress that insects could really do without, and it's for most of them bad news, I'm afraid.

Eva - And so is climate change in general a big driver of the insect loss? How many insects are we at risk of losing with climate change?

Dave - Well, we are seeing a massive decline in the abundance of insects. Many insects have fallen in numbers by 50% or more in the last few decades. Probably most of that's been driven by habitat loss, primarily the growth of pesticide use in farming and gardens and so on and things like light pollution and invasive species and a whole bunch of other factors. And climate change is starting to kick in now and there's growing evidence that it's beginning to have an impact, but obviously unfortunately, that impact is likely to get much worse as climate change accelerates into the future.

Eva - And you mentioned different insects ending up in different locations. Can we expect any insects from the sort of warmer regions now to end up in countries like the UK, which are a little bit cooler?

Dave - Yeah, we can. I mean, in fact, a few have already invaded from the south. And so we do every year get one or two new species turning up and we may also rather worryingly have malaria-spreading mosquitoes back in Britain within the not too distant future, which would not be good news.


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