In some simple models of trade, a country may choose to specialize in the production of a single good. Which is not an argument against specializing in a single good in the real world? Unexpected events such as natural disasters or sudden changes in taste and demand could cripple a single industry. New technology or cheaper substitutes could replace the good. Curved production possibilities curves suggest increasing costs and diminishing returns. Specialization in a single good makes dumping easier and more effective.