Reuters: Wal-Mart Stores Inc said on Thursday it will cut its worldwide plastic shopping bag waste by an average of 33 percent per store by 2013, an effort the world’s biggest retailer said could eliminate more than 135 million pounds of plastic waste globally. To meet that goal, Wal-Mart stores will give out fewer bags and encourage shoppers to use reusable ones. The announcement is part of the discount retailer’s overarching goal of one day creating zero waste. It also comes …