Japanese Monks Recorded the Climate for 700 Years
Some of the oldest continuous historical records from around the world show us how dramatically the climate has changed.
Lake Suwa sits in the Kino Mountains of central Japan, in a region sometimes called the Japanese Alps. When the lake freezes over, daily temperature changes cause the ice to expand and contract, cracking the surface and forcing it upward into a ridge.* Legend has it that the ridge, called the omiwatari, is formed by the feet of the Shinto gods as they cross the lake. Every year since at least 1443, the priests who live at the shrine on the edge of Lake Suwa have carefully recorded the date the ridge appears.
In 1693, on the other side of the world, a Finnish merchant named Olof Ahlbom started recording the date and time of the spring ice breakup on the