Guan also noted that beer crops aren't the only ones likely to be affected by climate change.
During severe climate events, global beer consumption would decline by 16 percent, or almost 30 billion litres - equal to all the beer quaffed each year in the United States, Guan and an worldwide team of researchers reported in the journal Nature Plants.
He pointed to a fall in barley yields in the United Kingdom this spring as proof of climate change's effect on the crop.
As a result, the cost of beer could soar.
This is not a drill: As climate change worsens, there could be a beer shortage.
On top of rising sea levels and extreme weather, scientists have predicted that human-caused climate change will result in another dire effect: a disruption in the global beer supply.
Beer is the most popular alcoholic drink in the world by volume consumed, said researchers at the University of East Anglia (UEA) in the UK.
"While the effects on beer may seem modest in comparison to numerous other - some life-threatening - impacts of climate change", he added, "there is nonetheless something fundamental in the cross-cultural appreciation of beer".
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Only the highest quality grain - less than 20 percent - is used to make beer, with most of the rest used as feedstock.
"Changes in barley supply due to extreme events will affect the barley available for making beer differently in each region because the allocation of barley among livestock feed, beer brewing and other uses will depend on region-specific prices and demand", it read.
Beer prices in the wake of these disruptive weather events would, on average, double.
Whether the best- or worst-case scenario plays out, beer drinkers in Ireland, Canada, Poland and Italy will likely see prices increase the most, the study says. "Nevertheless, there is little doubt that for millions of people around the world, the climate impacts on beer availability and price will add insult to injury".
Co-author Dr Nathan Mueller, also from the University of California at Irvine, said: "Current levels of fossil fuel consumption and CO2 (carbon dioxide) pollution - business as usual - will result in this worst-case scenario, with more weather extremes negatively impacting the world's beer basket".
Even under the two middle-range climate models used in the study, beer consumption is forecast to fall by an average of around 2 billion liters in China alone.
Saying that the beer industry "certainly understands and is already preparing for shifts in climate", the BA's economist Bart Watson and supply chain expert Chris Swersey write that barley production has always shifted geographically - while production efficiency "continues to grow over time". Consumption in the US could decrease by between 1.08 billion and 3.48 billion litres, they said.