North Pole sign

The North Pole is a busy place each spring, with dozens of scientists, tourists and adventurers visiting to test their limits or probe the atmosphere, ice, and sea below for clues to climate change. Here Nicolas Mingasson, a Frenchman who has helped run a base camp near the pole for 10 years, hikes near a sign and pole erected about 30 miles from the real thing by oceanographers from the University of Washington. The past tense is used because the sea ice is shifting several miles a day. You can learn more in my new book on the once and future Arcitc, which is written for the whole family and follows my 3 recent Arctic reporting trips, including one to the North Pole. The first chapter of the book, The North Pole Was Here can be read online: www.nytimes.com/learning/globalwarming .