Wine-Searcher) - Winemakers in the sweet wine appellations of Bordeaux are concerned that a proposed train line will alter their special microclimate.

A planned high-speed train line due to be built in 2027 could endanger the special conditions for making one of the world’s most precious sweet wines, claim producers.

Railway officials refute the claims, but local politicians and winemakers are ready to take their case to the European Court of Justice. The dispute bears an echo to the ongoing fight between the Italian government and Lugana winemakers over a high-speed rail link, which will destroy vineyards and threaten losses during the construction period.

The feasibility study for the line in southwest France was confirmed by the government in the fall of 2013 and incorporates two major high-speed lines, one that links Bordeaux with Toulouse and the other, Bordeaux with Dax. It is the line running to Dax, northeast of the swanky Atlantic seaside resort of Biarritz, which goes through the valley of the Ciron River, credited with providing Sauternes and other sweet wine appellations with their individual microclimate.

A public inquiry will close Monday, and yesterday Philippe Dejean, president of the Union des Grands Vins Liquoreux de Bordeaux, gave a rallying cry, "we call on all who love sweet wines to make known their displeasure". The union groups together the eleven sweet wine appellations in Bordeaux, the most prestigious being Sauternes and Barsac.

Dejean said that he was "very worried" about the proposed routing of the future high-speed line, which, although it will not go through the vineyards themselves, is planned to run across the Ciron Valley. The valley is an area of high humidity, protected by Natura 2000 (a Europe-wide network of protected natural areas) and it is this that gives the special micro-climate.