Yva Momatiuk & John Eastcott / Canoe on lake with calcium tufa formations, Mono Lake, California

Yva Momatiuk & John Eastcott / Canoe on lake with calcium tufa formations, Mono Lake, California

Norbert Wu / Kayaker paddling around ice floes from LeConte Glacier which is receding and showing evidence of global warming, LeConte Bay, Alaska

Shaun Barnett / Sea kayaking with icebergs, Tracy Arm, Tracy Arm-Fords Terror Wilderness, Alaska

Mark Moffett / Giant Sequoia (Sequoiadendron giganteum) climbed by Steve Sillett as part of canopy research project, Sequoia National Park, California

Yva Momatiuk & John Eastcott / Canoe on lake with eroded sandstone cliffs, Antelope Canyon, Lake Powell, Glen Canyon National Recreation Area, Utah

Yva Momatiuk & John Eastcott / Canoe on lake with eroded sandstone cliffs, Antelope Canyon, Lake Powell, Glen Canyon National Recreation Area, Utah

Yva Momatiuk & John Eastcott / Canoe on river in sandstone plateau, Green River, Canyonlands National Park, Utah

Yva Momatiuk & John Eastcott / Canoe on river, Snake River, Hells Canyon National Recreation Area, Idaho

Yva Momatiuk & John Eastcott / Canoe on river, Snake River, Hells Canyon National Recreation Area, Idaho

Yva Momatiuk & John Eastcott / Canoe on river, Snake River, Idaho

Daniel J. Cox / Tourists in canoe in winter, Jackson Lake, Grand Teton National Park, Wyoming