Seattle Times: It’s easy to see how a person might develop a deeper appreciation for Mother Nature by hiking the Alps or climbing Mount Kilimanjaro. Then again, that traveler would contribute to global warming by getting on an airplane and flying across the world. What to do? It’s a question that REI, the Kent-based retailer of outdoor gear and apparel, asked itself after examining its impact on the environment. The retailer’s REI Adventures unit sells vacation packages to people who …