Britain has just recorded its second-best butterfly season in 16 years. More than 100,000 volunteers counted almost 1.4 million butterflies and day-flying moths, while painted lady numbers jumped 335% compared with last year. Holly blues and gatekeepers recorded their best results since the Big Butterfly Count began. Brilliant news for butterflies? Not necessarily.
The same extreme weather which brought adult butterflies out in huge numbers may have been devastating the generation coming behind them. Adult butterflies thrive in hot, sunny weather. Caterpillars still need plants. And after five heatwaves and prolonged drought, grasses, wildflowers and other foodplants have been shrivelling across Britain. There are now fears that caterpillars could have died in sufficient numbers to contribute to a population crash next year.
We have seen the pattern before. Excellent butterfly seasons in 1976 and 1995 were followed by crashes, with drought playing a major role. Some species are already struggling. Speckled woods, green-veined whites and ringlets were all recorded in below-average numbers this summer and have declined by 44%, 54% and 39% respectively since 2011. So millions of butterflies flying around during a heatwave tells us surprisingly little about what is happening beneath them.
And beneath them, Britain is dry.
Much of England and Wales has been experiencing significant water storage deficits. The driest parts of southern England would need unusually high rainfall to replenish them, with those deficits expected to persist for months.
The effects are reaching our food too.
The UK has just experienced its hottest summer on record, with temperatures reaching 38.1C at Kew Gardens. Cauliflowers, broccoli and cabbages have struggled badly enough that gardeners are now being advised to consider crops better able to tolerate hotter and drier summers. This is what climate breakdown looks like. Not one spectacular disaster, but ecosystems being pushed further and further from the conditions in which they developed.
And animal agriculture belongs in this conversation. An alternative method of calculating responsibility for present-day warming produces a radically different picture from conventional greenhouse gas accounting. It counts gross land-use emissions rather than net emissions, incorporates historical deforestation and includes both warming and cooling emissions. Using that method, agriculture accounted for 60% of effective radiative forcing since 1750. Agriculture was estimated to have caused 0.74C of net global warming between 1750 and 2020, with 86% of that attributed to animal agriculture.
A huge part of the problem is land. Animal agriculture occupies enormous areas while simultaneously producing methane, and restoring land currently used for animal agriculture was estimated to offer about 540 gigatonnes of CO2 carbon potential.
None of this makes ending fossil fuel use less urgent. It means we cannot tackle climate breakdown while treating animal agriculture as some minor side issue. The same analysis explicitly calls for quitting fossil fuels while also highlighting forests, land restoration and animal agriculture.
Butterflies can fill our gardens during a record-breaking summer while the plants their offspring depend on die beneath them. A high butterfly count is not the same thing as a healthy ecosystem. If we want butterflies to survive the climate crisis, celebrating a bumper summer is not enough. We need to confront what is heating their world.