IN THEORY, the world has too much carbon dioxide. In 2015 the Paris climate agreement set limits on emissions of the gas to prevent global temperatures rising by more than two degrees Celsius above those of pre-industrial times. But in practice, makers of food and drink in Europe have found that they cannot find enough of the gas. And this unlikely shortage is likely to get worse in future.

Food-grade CO 2 is a vital ingredient: it puts the fizz in carbonated drinks and beer, knocks out animals before slaughter and, as one of the gases inside packaging, delays meat and salad from going off. A shortage of the stuff has therefore created havoc in foodmakers’ supply chains. Heineken, a Dutch brewer, and Coca-Cola, an American drinks giant, have been forced to close some of their European plants. JD Wetherspoon, a British pub chain, ran out of some beers. Scotland’s largest pig slaughterhouse was forced to shut. On June 29th Warburtons, a British baker, said that the problem had affected crumpets, closing down half its production of the snacks (the affected bakeries have since reopened).

Increased demand for food and drink due to the World Cup and sunny weather in northern Europe is only half the story, says Ned Hammond of Berenberg, a bank. Unlike America, which gets most of its carbon dioxide from natural wells, 50% of Europe’s comes as a by-product of ammonia production; a further 30% stems from processes for making hydrogen and bioethanol. Those sources of supply tend to be seasonal. For instance, three out of Britain’s five ammonia plants have been closed for maintenance—mostly for economic reasons. Farmers are cutting back on fertiliser use in the summer months, putting pressure on prices. And high prices for the natural gas from which ammonia is made have squeezed margins.