????因此，西班牙生產的這種小裝置在國際市場上將毫無競爭力，除非西班牙貨幣對德國貨幣的匯率能降至西班牙單位勞動力成本低于德國的水平。歐元誕生前，這樣的貨幣貶值過程經常會出現。但現在已經不可能。

????為了搞清危機怎么會突然爆發，不妨先簡單回顧一下歐元從救世主變為破壞者的歷程。正是歐元的影響，致使歐元區強國和弱國之間的單位勞動力成本差距較歐元誕生前進一步擴大，而意大利、希臘則喪失了之前藉以維持經濟增長的重要緩沖機制。

弱國更弱

????為了簡單一點，我們把歐元區分為兩部分，一部分是“核心”強國，主要是德國、荷蘭和奧地利，另一部分則是“南部”地區，包括意大利、西班牙、希臘和葡萄牙，以及地理上不屬于該區域但同樣深陷困境的愛爾蘭。即使是在1999年1月1日歐元誕生前，南部國家的利率正處于大幅下降通道。到2005年左右，消費者和政府的借款利率不到5%，低于十年前的12%。信貸猛增，寬松的貨幣主要流向了那些無外國競爭的產業，即經濟學家所謂的“非外貿產業”，包括從房地產、保險、景觀設計到美發護發等眾多行業。

????因此，這些嚴格內需型產業的薪資和價格飆升。從90年代末到00年代末，歐洲南部國家的價格增幅平均高出德國和其他核心國家1.5%。

????卡內基基金會（Carnegie Endowment）駐華盛頓的經濟學家烏里?達迪什稱：“偶們的單一貨幣政策對弱國而言太為寬松，而對德國和北部國家而言又過緊。”寬松的貨幣政策使得歐洲南部國家的消費者和政府的借款利率遠低于國內通脹率，鼓勵他們背負高額債務，其中主要來自國外借債。

????薪資上漲是另一個棘手的問題。非外貿產業的繁榮發展導致勞動力市場供不應求，出口行業的薪資也水漲船高，因為他們只能與建筑行業爭奪人手。除了愛爾蘭，歐元區弱國大多并沒有采取什么措施來改善剛性的勞動力市場。而且，事實上這些國家的法律更多地服務于確保薪資的增速高于生產率的增速。嚴格的勞動法規和本國勞動力市場需求的猛增兩相結合，導致截至2007年的十年間，歐洲南部國家的薪資每年增幅高達5.9%，比歐元區核心國家高出了2.7個百分點。

????但歐洲南部國家的薪資高增長難以持續。單一貨幣政策對德國的影響正相反：在德國，利率太高，抑制了經濟增長。德國的薪資增幅顯著低于希臘和西班牙。這又回到了單位勞動力成本。從2000年到2010年，希臘薪資增長了36%，意大利和西班牙增長了31%，愛爾蘭增長了29%。而德國的增幅只有4%。因此，德國和其他核心國家獲得了巨大的競爭優勢，而南歐國家則淪落到靠借貸度日。美國和中國（也與德國）一樣，兩者同樣也受益于美元和人民幣兌歐元匯率的下跌。

????Spain can still sell its widgets abroad, but only if its currency declines versus the German money to the point where its wages are lower than German wages. That adjustment process was constantly happening in the pre-euro days. Now, it can't happen.

????To understand how the crisis struck so unexpectedly, let's briefly examine the euro's savior-to-spoiler history. It was the euro's influence that caused unit labor costs in the strong vs weak economies to diverge far faster than they did in the pre-euro days, and that simultaneously eliminated the crucial shock absorber that allowed an Italy or Greece to keep growing in the past.

The weak get weaker

????To simplify, we'll divide the eurozone into the two parts, the "core" stronger economies, chiefly Germany, the Netherlands and Austria, and the "southern" zone of Italy, Spain, Greece and Portugal, and one ailing nation that doesn't belong geographically, Ireland. Even before the euro was introduced on January 1, 1999, interest rates were falling sharply in for the southern countries. By the mid-2000s, consumers and governments were borrowing at less than 5%, compared to 12% a decade earlier. Credit exploded, and the easy money flowed mainly into industries that don't face foreign competition, what economists call the "non-traded sector," encompassing everything from real estate to insurance to landscaping and hair care.

????As a result, wages and prices in those strictly domestic industries soared. From the late 1990s to the late 2000s, prices rose an average of 1.5% faster in the southern countries than in the Germany and rest of the core.

????"The single monetary policy was too loose for the weaker countries, and too tight for Germany and the northern nations," says Uri Dadush, an economist at the Carnegie Endowment in Washington, DC. The easy money allowed both consumers and governments in the southern nations to borrow at rates far lower than the pace of inflation inside their borders, encouraging both to pile on huge debt, chiefly from abroad.

????The march of wages was another daunting problem. The boom in the non-traded sector caused a tight labor market, and drove up pay for exporters who had to compete with the construction industry for workers. It didn't help that, with the exception of Ireland, the weaker countries did nothing to tame their extremely inflexible labor markets. The laws in those countries are virtually designed to raise wages faster than productivity growth. The combination of rigid labor laws and the explosion in domestic demand caused wages in the southern zone to jump 5.9% a year for the decade ending in 2007, 2.7 points faster than in core Europe.

????The southern zone's growth spurt was ephemeral. The blanket monetary policy had precisely the reverse effect on redoubtable Germany, where rates were too high, restraining growth. German wages didn't see nearly the increases that Greece or Spain experienced. That brings us back to unit labor costs. From 2000 to 2010, they rose 36% in Greece, 31% in Italy and Spain, and 29% in Ireland. For Germany, the figure was 4%. So Germany and the other core countries gained an enormous competitive edge while the south lived on borrowing, as did the U.S. and China, which also benefited from a fall in the dollar and yuan versus the euro.