A large dike protects a quaint village and nearby fields from the waters of Lake IJsselmeer north of Amsterdam. The freshwater lake, once part of the Zuiderzee, an arm of the North Sea, was dammed off in the 1930s. Over the next few decades, the country diked and drained several large polders from the lakebed to create new land for fields and villages, and by 1968, nearly 800 square miles of former bay had been reclaimed from the sea. But the sea is fighting back. Sea levels are rising 0.1 inch per year along the Dutch coast—50 percent faster than during the twentieth century—while reclaimed farmlands within the polders are subsiding around 0.3 inch per year, forcing the Netherlands to spend $20 billion to raise the dam 6.5 feet and build surge barriers on top of it. Reclaiming farmland is not a new challenge in the Netherlands. Around 1740 in Kinderdijk, the Dutch built a system of windmills to drain the polders there. Nineteen of the classic structures remain and are kept in working order in case the modern diesel pumps that replaced them fail. More than a quarter of the Netherlands lies below sea level.
