‘It’s a warning’: UK nature chief sounds alarm over ecosystem collapse as butterfly numbers halve

The collapse in British butterfly populations is a "warning from nature" about the resilience of the UK's ecosystems, says England's nature chief, raising concerns about threats to national food security as the planet continues to heat.

Tony Juniper, the chair of Natural England , says new data showing a sharp fall in butterfly populations this summer was probably the consequence of habitat loss and the use of pesticides, making the insects less resilient to extreme weather fluctuations: the scorching heat and wetter weather driven by global heating.

Figures from Butterfly Conservation this week showed observed butterfly numbers had almost halved to 935,000 – the lowest ever total in the 14-year history of the UK count. Species including the common blue, the small tortoiseshell and Scotch argus recorded their lowest ever figures, according to the data.

"The butterfly data from 2024 is an early signal of what lies ahead," says Juniper . "It's a warning from nature as to how far down the track we've gone towards taking the resilience out of natural systems. Of course, this circles back on people in the end in terms of our food security and other factors that depend on that web of life still functioning.

"This year's butterfly disappearance hopefully will lead people to be thinking about how they can have food plants in their garden for larvae and flowers for the adult insects to be able to feed on, but also hopefully be thinking about some of the bigger questions that link that decline in insects to climate change or the style of agriculture that we've become used to feeding us," he says.

Juniper says the UK should be doing more to improve the resilience of ecosystems to climate change, pointing to the country's national parks and new housebuilding plans as opportunities to invest in nature. England's national parks are in a poor state , with warnings that they are failing nature, according to recent analysis by the Guardian.

Speaking ahead of the biodiversity Cop16 in Colombia next month, which will be the first time Labour's new government enters the international stage on the environment, England's nature chief says he welcomes comments from senior government ministers committing to international leadership on the climate and nature crises , underscoring the importance to the UK's credibility of action at home.

"I'm delighted to hear the sentiments being put across now about the UK wishing to lead on the global stage. That couldn't be more welcome given the vast scale of what we're now dealing with in trying to avert this mass extinction and the effects of global warming," he says. "Keeping a focus on what we are delivering domestically is always going to be a vital part of what we can bring to the international discussions."

To protect 30% of the UK for nature this decade – the headline target in the UN biodiversity agreement – Juniper says that new national parks are not necessarily required, but that the country needs a "mosaic" of different protected habitats. He says the new government's housebuilding plans were a big opportunity to invest in wildlife habitats in England, particularly through the creation of "wild belts" around cities.

"National parks were declared for their beauty, not necessarily including their wildlife," he says. "This is not to diminish what they've delivered, because they've done an enormous amount of good ... but now we need to make an extra step towards nature recovery."

Campaigners have called for an overhaul of how England's national parks are managed after a Guardian investigation showed the boards that oversee England's national parks were dominated by men and severely lacking in diversity, with farmers outnumbering conservation experts two to one. Juniper says reformed national parks could help reverse biodiversity loss.

"If we do more landscape designations, it's not necessarily going to help us meet that 30% target unless it's got a stronger biodiversity element in it," he says. "At Natural England, we do see a case for perhaps a modernised version of national parks that would be much more people-facing, which would be about nature recovery, and perhaps linked more to the edge of urban areas.".

"It is about developing the future mandate for nature as a result of people having a personal connection with it. If most of us live in city centres bereft of natural areas, then that public mandate, over time, will evaporate."