1. OFFSET YOUR ADVENTURE: Starting this year, Australia-based Intrepid Travel, which operates on seven continents, will offset a select number of trips with the goal of going carbon-neutral by 2010. Our favorite: a 22-day Annapurna Circuit epic ($1,100; intrepidtravel.com).
2. LEND A HAND: UK-based Blue Ventures raises the conservation-trip bar with its new six-week journey to Leleuvia, Fiji, where guests scuba-dive to research reef health and work with local communities to establish a proposed marine park ($3,200; blueventures.org).
3. TREAD LIGHTLY: Want a wallet-friendly, low-impact trip to remember? According to green-travel guru Hitesh Mehta, the best out there is Angel-Eco Tours' new seven-day trek to Venezuela's Niagara-dwarfing Angel Falls, in wild Canaima National Park ($1,500; angel-ecotours.com).
TRIP OF THE YEAR: ASIA
walk to kanchenjunga
16 DAYS, FROM $4,300
Pioneering adventure outfitter Mountain Travel Sobek celebrates its 40th anniversary with a series of back-of-beyond trips led by top guides. Our favorite: this northern-Sikkim trek, which ends at the base camp of 28,169-foot Kanchenjunga. After two nights in Gangtok, capital of Sikkim, a team of porters, 12 guests, and a seriously illustrious guideJamling Norgay, son of some guy named Tenzingset off for ten days of trekking through remote high-alpine valleys near the Tibetan border. "It will be like hiking in Nepal in the sixties," says Narendra Gurung, Sobek's director of Asia operations. October 31November 15; mtsobek.com.
Climb Live Volcanoes
21 DAYS, $2,800
By the end of KE Adventure Travel's three-week Living Mountains journey, you'll have trekked through remote Javanese villages and 15th-century stone temples. Fun stuff, but nothing compared with the trip's primary thrill: watching the sun rise through clouds of gas and cinder from the summit of an active volcano. The voyage takes guests from Jakarta to eight feisty volcanoes on the islands of Java, Bali, and Lombok. Eight-hour treksand a few nights of camping in Javanese leopard countryare offset by nights sipping Bali Hai beer in rustic island resorts. Departures in July and September; keadventure.com.
12 DAYS, $3,600 PLUS $20 MEMBERSHIP FEE
Explore Mongolia's wildest scenery, from a lake about the size of Rhode Island to the Gobi Desert, where the mode of transport comes with two humps. Guests land in Ulan Bator and hightail it to 85-mile-long Lake Hövsgöl, known for its rich purple color. After four days of kayaking along shorelines, camping in traditional gers, and horse-trekking through 8,000-foot-high meadows in the nearby Khoridal Saridag range, it's Gobi time. Between two-to-six-hour camel rides and trips to the iconic 2,500-foot-high singing dunes, unwind at the solar-powered Three Camel Lodge. Five departures between June and September; rei.com.