Extreme weather caused by climate change can have devastating effects — and it turns out that not even beer is safe.

More frequent droughts and heat waves in the twenty-first century will reduce global production of barley, finds a study published on 15 October in Nature Plants ¹ . In turn, it finds, this will decrease the supply of beer and drive up prices, even under best-case-scenario models of climate change.

Many studies have explored how climate change will affect the production of staple foods such as wheat and rice, and some researchers have also looked at how luxury goods such as wine could be affected. But nobody has considered how beer will fare, says Dabo Guan, a climate-change economist at the University of East Anglia in Norwich, UK.

Guan and his colleagues combined a series of climate and economic models to predict how extreme weather produced by climate change is likely to affect barley crops ( Hordeum vulgare ) — and how this in turn will influence beer supply and pricing (see ‘Climate’s toll on beer’).

Beer production might seem like a trivial consideration when it comes to climate change. But Guan hopes that highlighting a single luxury product will get people thinking about the broad implications of global warming.

“"What I’m trying to emphasize here is that climate change will impact people’s lifestyle,” he says — even those of people in industrialized countries, who may be shielded from the worst effects of climate change on food supply.

Guan hopes that helping people understand how climate change could affect their daily lives will motivate them to take action against climate change. If people “want to drink beer when we watch football, then we have to do something”, he says.

Brewing storms

The team began by examining the chances of major droughts and heat waves in barley-growing regions on all six inhabited continents between 2010 and 2099. They considered four possible futures, from the best-case scenario, which sees relatively low levels of greenhouse-gas emissions during the twenty-first century, to the worst-case situation, in which emissions are high.

In each of these cases, the researchers found that the likelihood of extreme weather in barley-growing regions around the world increased compared with the number of similar events recorded in the late-twentieth and early twenty-first centuries. In the best-case scenario, this chance increased by a modest 4%, but the worst case saw a rise of 31%.

The researchers then simulated the effect of these droughts and heat waves on barley production by using software to model crop growth and yield on the basis of weather and other variables.

They found that, globally, this extreme weather would reduce barley yield by between 3% and 17%. Some countries fared better than others: tropical areas such as Central and South America were hit badly, but crop yields actually increased in certain temperate areas, including northern China and the United States. Some areas of those countries saw yield increases of up to 90% — but this was not enough to offset the global decrease.

Finally, Guan and his colleagues fed these changes in barley yield into an existing economic model that can account for changes in supply and demand in the global market. This enabled them to look at how reduced barley production would affect pricing and consumption of beer in countries, as well as trade between nations.

In the worst-case scenario, the reduced barley supply worldwide would result in a 16% decrease in global beer consumption in the years of extreme-weather events. Prices would, on average, double.

Cutting back

As the world’s largest overall consumer of beer, China would show the biggest national drop in beer consumption, drinking 4.34 billion fewer litres of beer each year. Even the United States — a rare case of a country actually producing more barley after climate change — would also see a decrease in national beer consumption, as it would be exporting more barley than it ever has before.

Meanwhile Ireland would see the biggest absolute price increase of the countries studied, with the price of beer going up by almost US$5 per 500 millilitre bottle, tripling the cost. That’s because changes in price are partly influenced by consumers’ willingness to pay — and Ireland is the world’s largest consumer of beer on a per person basis.

Other countries like the Czech Republic have cheaper beer to begin with, but could see a huge relative rise in price of more than 600%.

Even under the best-case scenario, globally, the model predicted a 4% reduction in beer consumption and a 15% increase in price.

Klaus Hubacek, an ecological economist at the University of Maryland in College Park, says the study does a good job of combining climate, agriculture and economic models. He wonders how other alcohol crops might be affected, and whether beer drinkers might switch to cider or other alcoholic drinks.

But worries about beer pale in comparison to projections how climate change could harm food security generally, says David Reay, a climate-change scientist at the University of Edinburgh, UK.

“The effect on beer is going to be the least of our worries,” he says, especially in the worst-case climate scenarios. Reay worries that this message could be diluted in studies such as Guan’s, which concentrate only on luxury items.

“I think in that kind of future, I probably will need a beer, because it will be pretty bad,” Reay says.