The package delivery giant's earnings will dramatically improve in the second half.It's been a challenging year for UPS (UPS 2.97%), and the stock declined 13% in the first half of the year, according to data from S&P Global Market Intelligence. The decline reflects the ongoing challenges caused by a decrease in delivery volumes and the increase in compensation costs resulting from a new labor contract agreed upon last year.UPS's challenging yearIt gets worse. Last year's protracted labor negotiations cause ...