Captain Cook's notes describe the disappearing Arctic ice wall.

Captain james cook's Arctic Expedition Ship, Resolution (Foreground) and Discovery, in1August 778 18, Icy Point Leaving Alaska, Etching in john weber, published in 1792. PD- The detailed record of Capt.James Cook, an American British explorer, who is famous for exploring Australia and Hawaiian Islands, has found new modern value: according to a new study, it helps climate change scientists to understand the degree of sea ice loss in Canadian Arctic ice sheets.

Note: Chart1778 In August, Cook and his crew made a map while exploring the Arctic, carefully recording the location and thickness of the ice that blocked the explorers. They are looking for a channel connecting the Pacific Ocean and the North Atlantic Ocean to provide a new maritime trade channel for Britain and the Far East.

Cook never found this passage, which is called the Northwest Passage today. However, his observations and those of the crew provided the earliest recorded evidence of the large-scale summer ice sheet in the Chukchi Sea at that time. That part of the Arctic Ocean lies between Alaska and Russia. Harry Stern, a researcher and author at the Center for Polar Science at the University of Washington, said that compared with modern sea ice observations, these records show great changes in the Arctic ice sheet-especially in recent years. Stern said in his research report that Cook was not the first explorer to search the Northwest Passage, nor was he the last. He was the first explorer to draw a map of the ice world, which divided the ocean north of the Bering Strait in two. Stern said Cook was also the first person to try to sail from the Pacific coast along the North American coast. He said: "At that time, it was a particularly urgent goal for Britain to find this route that could speed up and strengthen trade with the East." . In fact, in 1745, the House of Commons of the British Parliament enacted a bill to provide a reward of up to 20,000 pounds (about 24,978 US dollars) for the discovery and drawing of this passage according to the archives of the Royal Greenwich Observatory kept by the Digital Library of Cambridge University. Study climate and Arctic sea ice

Stern wrote a paper for Cook's climate scientists for the book Arctic Ambition: Captain Cook and Northwest Passage (Washington University Press, 20 15, 1). When Stern studied the archives of voyage 1778, he realized that he was studying the earliest detailed map of the Chukchi Sea ice margin. He said: "Before Cook's expedition, the map of this area did not provide too many details or was very inaccurate; Stern wrote that a map of Russia referenced by Cook shows that Alaska is an island,1778 August11,

Cook sailed through the Bering Strait, but in August of 18, he was suddenly blocked by the ice near Alaska, which seemed to be at least 10 or 12 feet high. He wrote in his diary.

In the diary entry of the next day, Cook described tracking the edge of sea ice hidden in fog by listening to the sound of roaring walrus (he called it "seahorse"). Stern pointed out that this may be the first time to use remote sensing technology to obtain the information of distant walrus, and an object can locate the position of sea ice by calculating the energy it releases.

An airtight wall cook searched for 1 1 day on the edge of the ice wall, but he couldn't find an opening all the way west to the Siberian coast. Cook was forced to retreat to the south. He vowed to continue the search the next summer, but he never returned to that area and died in Hawaii six months later.

Despite this, the researchers said, Cook's frustrated efforts collected important data about the Arctic ice sheet. His records of the location and extent of the impenetrable ice wall are very accurate, and these records can be used to align with later maps. This helped Scientology Stern tell USA-Today magazine that in order to find out the historical size and location of the ice edge and determine the way it changed over time, Stern said:

Moreover, for hundreds of years, the size of the first recorded ice wall Cook fluctuated every year, but it did not change significantly until the 1990s. He said that since then, the changes have been remarkable.

"The summer ice margin of the Chukchi Sea now extends hundreds of miles north than before," Stern said.

It was not until the early 20th century that Roald Amundsen, a Norwegian explorer, led an expedition from 1903 to 1906 that the Northwest Passage was completely navigated, although it was a relatively small ship. In 2007, the Arctic sea ice was at the lowest level in 30 years, and the passage was open enough to accommodate large cargo ships and research ships.

Cook may have found this elusive passage in 1778. What if the sea ice cover is more like today? Maybe, Stern told reporters today-but that doesn't mean it's easy.

Stern said: "One thing hasn't changed: sailing in snow-covered waters is still dangerous."

This discovery was published online in the journal Polar Geography on June 3rd, 165438.

This is an original article about life science.