Rising summer temperatures are impacting grape growers around the world, however today I will focus on France’s Bordeaux region.  Temperatures are expected to rise between 0.3°C and 1.7°C over the next 20 years. At this point global warming has benefited Bordeaux but that is about to change, especially if the grape crop is not somewhat modified. 

Growers are going to need to reconsider their mix of grapes as temperatures continue to rise.  The future of white varietals from the region may become non-existent while the existing proportion of reds, where 60% to 70% is currently Merlot, is already too great an amount.  Merlot is ideal in cooler regions where there is a shorter growing season. However, with temperatures increasing and the growing season getting longer, Merlot now ripens too quickly.  Many of these vines will need to be replaced with varietals such as Cabernet Sauvignon, which perform better in hotter climates with a longer growing season.

At least until now the increase in temperature and the resulting riper fruit have not had a detrimental effect on the quality of the wine. Instead, higher temperatures have made wine quality more consistently better. However, if warming continues the quality of the wine will begin to deteriorate.

It is well known that high temperatures can have harmful effects on grape composition, such as a decrease in anthocyanins (the pigmented molecules that give red wine its colour), as well as other molecules, that could cause unpredictable aromas.  The grape skins are also negatively impacted by higher temperatures.

Growers, scientists, and wine professionals all speculate that continued increases in temperature will negatively impact fruit and wine quality in the future. However, to date Bordeaux has successfully adapted to the quickly changing climate, but experts fear that the danger point is swiftly approaching.

Sláinte mhaith