British consumers are facing shortages of beer and crumpets, as supplies of carbon dioxide run low amid a record summer heatwave. An unusually high number of the plants that produce the gas, which is emitted in large quantities as a byproduct of fertiliser production, have closed for maintenance this summer. Whilst some breweries and plants produce their own CO2, the shortage is having repercussions across the food and drink supply chain in Europe. Pubs in the U.K.