根据下面资料，回答题
If the Europeans thought a drought--a long period of dry weather--was something that happened only in Africa, they know better now． After four years of below-normal rainfall( in some cases only 10 percent of annual average),vast areas of Europe are dry and barren(贫瘠)． Water is so low in the canals of northern France that waterway traffic is forbidden except on weekends． Oyster(杜蛎)grows in Brittany report a 30 percent drop in production because of the loss of fresh water in local rivers necessary for oyster breeding． In southeast-ern England, the roiling green hills of Kent have turned so brown that officials have been weighing plans to pipe in water from Wales． In Portugal, farmers in the southern Alentejo region have held prayer meeting for rain--so far,in vain．
Governments in drought-spread countries are taking severe measures． Authorities in hard-hit areas of France have banned washing cars and watering lawns． In Britain,water will soon be metered, like gas and electricity,"The English have always taken water for granted,"says Graham Warren, a spokesman of Britain´s National Rivers Authority． "Now they´ re putting a price on it．" Even a sudden end to the drought would not end the misery in some areas． It will take several years of unusually rain, the experts say, just to bring existing water reserves up to their normal levels．
What does the author mean by saying "they know better now"?