ナショナルジオグラフィックさんのインスタグラム写真 - (ナショナルジオグラフィックInstagram)「Photos by @erintrieb | For the past several years, I’ve become fascinated with climbing high-altitude glaciers. On a recent climbing expedition in Mexico, I learned that this country, which is typically known for its desert landscapes and pristine beaches, is home to several towering volcanic peaks, including Pico de Orizaba (also known as Citlaltépetl) at 18,491 feet (5,636 m), the highest volcanic summit in North America and the continent’s third highest mountain after Denali in Alaska and Canada's Mount Logan, and Iztaccihuatl at 17,160 feet (5,230 m), Mexico’s third highest peak. Pico de Orizaba and Iztaccihuatl host what were once massive glaciers. However, the glacial ice sheets on both peaks have diminished substantially over the past century; Pico de Orizaba’s glaciers shrank 90 percent from 1958 to 2001. Scientists predict that the last remaining glaciers in Mexico will disappear within the next 10 years. In these photos: A cloud swirls around climbers as they ascend Iztaccihuatl’s slopes. Caleb Burns (front), with SWS Mountain Guides, examines the route while leading clients up a trail. Climbers traverse Iztaccihuatl’s glacier after reaching the summit. Iztaccihuatl’s dry slopes are a result of rapid glacier melt. This view of the remaining snow on Pico de Orizaba’s peak is from the town of Tlachichuca. For more stories on the world’s mountains, follow @erintrieb.」9月5日 4時00分