How to get your friends off the fence on climate change:
IF THE sinking Maldives aren't enough to galvanise action on climate change, could losing a classic beer do it? Climatologist Martin Mozny of the Czech Hydrometeorological Institute and colleagues say that the quality of Saaz hops - the delicate variety used to make pilsner lager - has been decreasing in recent years. They say the culprit is climate change in the form of increased air temperature.
Mozny's team used a high-resolution dataset of weather patterns, crop yield and hop quality to estimate the impact of climate change on Saaz hops in the Czech Republic between 1954 and 2006. Best-quality Saaz hops contain about 5 per cent alpha acid, the compound that produces the delicate, bitter taste of pilsners.
The study found that the concentration of alpha acids in Saaz hops has fallen by 0.06 per cent a year since 1954, and models of hop yields and quality under future global warming scenarios predict bigger decreases (Agricultural and Forest Meteorology, DOI: 10.1016/j.agrformet.2009.02.006).
It's not just Czech hops that are at stake here, says Francesco Tubiello, a crop specialist at the European Commission and a lead author of the agriculture chapter of the IPCC Fourth Assessment Report. "The famous hop-growing regions of eastern Germany and central Slovakia are facing the same situation," he says.
