Liquefied Natural Gas (LNG) market is one of the fastest growing energy markets. As a result, the problem of fulfilling the growing energy demand is intriguing to researchers both in academia and industry. In this research, Green-House-Gas emissions are incorporated into the traditional supply chain optimization model for LNG markets. Its characteristics, i.e. relatively low price and environmental benefits over other fossil fuels, along with the existence of Gas Exporting Countries Forum make it possible to explore the potential for Supply-Chain-Optimization to improve trade between exporters and importers. In this study, the objective function is the overall supply-chain profit, i.e. difference between selling revenue and operating and emission costs. Cap-and-trade policy is incorporated into the model to quantify emission costs. Accordingly, decision variables are the adequate required capacity, volume of shipped LNG to each market and allocation of exporters’ tankers to the routes. Preliminary results demonstrate the optimal capacity being lower than the capacity in competitive markets, while demand satisfied rate is improved. Moreover, tighter caps, in contrary to expectation, may lead to higher emissions. Finally, the conducted sensitivity analysis provides an optimal cap and tax for each market corresponding to the highest cost reduction and emission mitigation.