During the Gjøa expedition 1903-06 Ristvedt was the 1st engineer and also functioned as meteorologist and blacksmith and had the responsibility for the dogs.

Peder Ristvedt was born in Øvre Sandsvær county (now Kongsberg) 20 March 1873 on the farm Nedre Ristved as number six of nine children. His parents were Peder Ristvedt and Anne Sofie Hansdatter Berg. He married Hanna Marie (died 1944) and they had one child, Finn, who became a dentist in Kongsberg. His dental office is part of the exhibition at the Lågendals Museum in Kongsberg, and here are also several objects from Peder Ristvedt’s expeditions.

Peder Ristvedt took his sergeant’s exam at the Infantry Junior Officer School in 1893 and he was Roald Amundsen’s sergeant in the military. He thereby became the first to volunteer when Amundsen was looking for crew for his expedition through the Northwest Passage. Before the Gjøa expedition Ristvedt participated on Amundsen’s test voyage with the Gjøa to Northeast Greenland in 1901 and was away for five months.

All the pemmican on the Gjøa – both for men and dogs – was prepared by Peder Ristvedt before departure from Kristiania (Oslo) in 1903. This was done under the supervision of professor and nutrition expert Sophus Torup, who had also been Nansen’s adviser in connection with the first Fram expedition. 

Ristvedt was, together with Amundsen, the first who proved that the magnetic north pole moved. This happened when Ristvedt and Amundsen in 1904 left with a dog team to observe the position of the pole. Before this Amundsen and three of his men had already tried twice to find the magnetic north pole, but both times they had had to turn back because of the cold. When Amundsen and Ristvedt started the third time, Amundsen was unlucky and broke the glass on the only chronometer they had with them. Since a chronometer was necessary for the magnetic observations, Ristvedt returned to the Gjøa to fetch a new one. On this trip there and back by dog sledge Ristvedt covered 100 km in 24 hours non-stop. On 26 April Amundsen and Ristvedt reached the position where James Clark Ross had found the pole in 1831, but it was not until three weeks later that they found the new position of the magnetic north pole.

In 1905 Ristvedt carried out, together with Godfred Hansen, a sledging trip to the unknown area of the east coast of Victoria Land. On 26 May they reached their furthest-north position which they named Cape Nansen. One month after they had left the Gjøa, they arrived back after a trip of 1300 km.

After Peder Ristvedt’s return from the Gjøa expedition, he was called ”Gjøa-Peder”, and he held several talks about the expedition. Some of the money he received for this he donated to the ”Øvre Sandsvær’s Skier Society”. He was appointed knight 1st class of the St. Olav’s Order in 1906 for ”bravery as a sailor”. The main reason was that he, while on the Gjøa had prevented a dangerous fire from spreading. It was particularly the store of nitrocellulose (guncotton) that was used to blow channels in the sea ice that could have caught fire. If the fire had spread to this store, the ship would probably have been blown apart. Ristvedt was also given a personal reward for this deed, a gold pocket watch with chain.

In 1907, a year after his return with the Gjøa, Ristvedt took a business school exam and the following year he got a job at the Kristiania Customs House as an inspector at the Ship’s Customs.

In his later days Ristvedt lived with his wife on a small farm in Askim in Østfold. The sources relate that Askim in the 1930s was a popular place to move to, especially for retired civil servants and businessmen. This may have been due to low taxes and electricity prices. Both Peder and his wife were buried in the churchyard in Askim, even though Peder lived in Sandsvær with his niece for the last years of his life.

The street Peder Ristvedts vei in Kongsberg was named in 1973, and in 1997 a memorial stone was erected to honour him in Askim.