Busk was a notable mountaineer, gaining membership of the
Alpine Club while an undergraduate, after making the first winter ascent of the north face of
Pic du Midi d'Ossau. Towards the end of his time at Princeton he visited the
Rockies and
Banff on a climbing tour. Whilst in the
Ramparts, they attempted the first ascent of
Redoubt Peak, , a mountain on which two climbers, F. H. Slark and F. Rutishauser, had disappeared without trace the previous year. Busk was climbing with
Joe Johnson and Hans Fuhrer. On a ledge Fuhrer found
"Slark’s rucksack with a pair of mountain boots in addition to the rest of the stuff; these were small boots, and from his size Slark must have had big feet, so I think it probable that Rutis was climbing in stockinged feet on the cliffs directly below the summit when they fell. It was a place we looked at in horror, and circumnavigated. I am firmly convinced that they fell and were not struck by falling stones", on the summit they found a tin containing the names of the missing climbers. Busk inferred that Slark and Rutishauser ascended the W. ridge and were trying to descend the S. face when the accident occurred. Busk's party also made the first ascent of Casemate, . Busk wrote that he tried to "make the most and hope for the best of any post" and during each diplomatic posting he found time to explore some of the 'local' mountaineering challenges. It was not unknown for Busk to recruit mountaineers passing through his postings to join him on such excursions. He recounted some of his mountain activities in Iran in the
Alpine Journal and also those in Ethiopia, including the Batu Range which, as far as Busk could ascertain, had not previously been visited by any European party. Whilst stationed in Ethiopia he travelled by road from
Addis Ababa to the
Ruwenzori Mountains where, with Arthur Firmin, he climbed two previously unidentified peaks on the south ridge of
Mount Stanley. Whilst in Venezuela in the early 1960s, he made regular visits to the
Sierra Nevada de Mérida and one of his visits there resulted in the
first ascents of the rock spire of El Vertigo and of the south-west face of El Abanic, one member of that party was
George Band who had made the first ascent of
Kangchenjunga. His obituary in
The Times said that his "greatest contribution" was his work as chairman of the library of the Alpine Club, culminating in the production of a 600-page catalogue and the 1981 exhibition "The Treasures of the Alpine Club". ==Recognition==