That decline would force rises in the price of the grain. Salinger says climate change could cause a drop in beer production within 30 years, especially in Australia, as dry areas become drier and water shortages get worse.
Salinger says beer could get more expensive -- and some pubs might have to go without.
Brewers say they're already feeling the pinch of rising prices. One industry executive says barley growers are grappling not only with climate change, but also with competition from other industries using land, like the dairy industry.