The summer of 1976 saw standpipes in the streets and billions of seven-spot ladybirds swarming in search of food.
It was the hottest English summer since records began over 350 years ago – the mercury topped 32 °C for 15 consecutive days across much of southern England, and some regions received no rain for 45 days straight.
Since then, the UK has warmed by a full degree Celsius and experienced numerous bouts of extreme weather, from heavy rainfall and flooding to heatwaves and drought; yet no single year has caused so many butterfly and moth species to crash simultaneously.
"It was the culmination of a two-year event."
said Dr Phil Platts, Postdoctoral Research Associate in York’s Department of Biology and co-author of the study.
This was initially good for butterflies and moths, and their numbers boomed.
The study also looked at the impact of extreme weather on birds, determining that the cold winter of 1981-82 had the biggest effect on their numbers.
"This seems to be truer of short-lived species that can multiply rapidly, like butterflies and moths, than of the birds we studied."
However, global warming is projected to increase the frequency of extreme weather events such as heatwaves and drought, and it is likely that some of these will generate even greater population changes than we have seen so far.
Professor Chris Thomas, senior author in York’s Department of Biology, said: "If we want to avoid a future super-heated drought that will put 1976 in the shade, then we need to address the root cause of climate warming – greenhouse gas emissions.