After suffering through their worst two-year stretch in history, local ports have begun climbing out of a deep hole brought on by the global economic collapse. Since January, trade volumes are up about 20 percent from 2009 – a dreadful 12 months labeled “the most difficult year in shipping history” by at least one shipping executive. Gains have been buoyed by imports and exports, which saw their largest increases since 2007. But the realities of high unemployment, massive personal debt and tight credit across America make the sustainability of recent gains highly questionable.