Sir

The so-called Northwest passage (between the Pacific and the Atlantic) has become fully navigable, as mentioned in your News story 'Arctic melt opens Northwest passage' (Nature 449, 267; doi:10.1038/449267b 2007). It is worth recalling that when Roald Amundsen led an east–west expedition through the Northwest passage on the ship Gjøa, it took him two and a half years to reach Gjøahaven (now called Gjoa Haven) in mid-August 1905. He wrote in his diary: “The North West Passage was done. My boyhood dream — at that moment it was accomplished. A strange feeling welled up in my throat; I was somewhat over-strained and worn — it was weakness in me — but I felt tears in my eyes.”

In June 1940, the Royal Canadian Mounted Police vessel St Roch left Vancouver to sail the passage from west to east. It docked at Halifax on 11 October 1942. In 1944, the St Roch returned to Vancouver by a more northerly route, cutting the time down to just 86 days. More recently, icebreakers and ice-strengthened ships have on occasion traversed the route. But by the end of the 2007 melt season, a standard ocean-going vessel could have sailed smoothly through, proof indeed that the Arctic summer ice is rapidly diminishing.