Hospitality and tourism firms have applied all three approaches, as outlined in several studies that discuss benefits and drawbacks of each (e.g., see Sigala 2008, Tepelus 2005, and Budeanu 2005, single-firm approach; Tapper and Font 2005, and Schwartz, Tapper, and Font 2008, joint sector approach; and Tour Operators Initiative [TOI] 2007 and World Tourism Organization [WTO] 2004, ABTA [Association of British Travel Agents] and TOI 2002, and TOI 2007, cross-sector approach). Given the drawbacks of the single-firm sustainability approaches, research in tourism sustainability has called for sustainability implementation from the joint supply chain management approach (e.g., Kolk, Levy, and Pinkse 2008; Sigala 2008). Among the issues facing single-firm sustain- ability initiatives (e.g., green programs and voluntary carbon offset schemes) are lack of transparency and reliability (e.g., for calculating emissions reductions and interpreting “reduction”), variability among schemes (e.g., different degrees and stringency for monitoring and verifying carbon reduction by third parties), complexity and consumer confusion, and inability to foster structural changes by changing the consumers’ and firms’ behavior (as the onus for offsetting is placed on the consumer rather than the polluter—in this case, airlines: Grossling et al. 2007; Mair 2011).