????富裕國家在過去7年經歷的經濟不景氣可以歸咎于發端于美國、最終失控的房地產泡沫。

????當然，也存在廣大金融體系監管不力等其他問題，這些都導致了這次經濟蕭條。但若沒有房地產泡沫，可能就不會出現金融危機。

????這就是為什么從加拿大到英國等國家類似于房地產泡沫的膨脹引發了經濟學家的擔憂，因為這些泡沫可能成為日后危機的催化劑。

????6月14日當周，國際貨幣基金組織（IMF）經濟學家朱民(音譯）發表了一篇題為《不能再繼續善意忽視房價高漲現象》（Era of Benign Neglect of House Price Booms is Over）的文章，對不斷高漲的全球房價發出了警告。如何判斷一個國家的房價是否過高？朱民給出了自己的解釋：

????“理論上，房價、租金和收入從長期來看都應當同步變動。如果房價和租金脫離基準線，人們將在購房和出租之間轉換，最終使得兩者保持同步。類似地，從長期來看，房價不可能脫離人們的承受能力（即他們的收入）太遠。因此，房價收入比常常作為衡量房價是否偏離經濟基本面的初步指標。”

????以下來自IMF的圖表顯示了這樣的分析結果，類似加拿大、比利時和瑞典等國家看起來都存在很大的房價泡沫：

????The economic slump that richer countries have suffered during the past seven years can be blamed on a runaway housing bubble that started right here in the U.S.

????Sure, there were other issues–like poor oversight of the broader financial system–that led to the crash. But without the real estate bubble, there would likely have been no financial crisis.

????Which is why the fact that similar-looking bubbles inflating in countries from Canada to the U.K. have economists worried that there might be other catalysts of future crises laying wait for us in the weeds.

????Last week, IMF economist Min Zhu published an article called “Era of Benign Neglect of House Price Booms is Over,” in which he sounded the alarm over rising global home prices. Zhu explains how he determines whether home prices in a particular country are overpriced:

????“Theory asserts that house prices, rents, and incomes should move in tandem over the long run. If house prices and rents get way out of line, people would switch between buying and renting, eventually bringing the two in alignment. Similarly, in the long run, the price of houses cannot stray too far from people’s ability to afford them––that is, from their income. The ratios of house prices to rents and incomes are thus often used as an initial check on whether house prices are out of line with economic fundamentals.”

????The following charts from the IMF show the results of this analysis, with countries like Canada, Belguim and Sweeden appearing to have large housing bubbles on their hands: