In 1956, the Soviet Union proposed to the US a joint bi-national project to warm the Arctic Ocean and melt some of the ice cap. As designed by Petr Borisov, the Soviet project called for a dam across the Bering Strait. It would block the cold Pacific current from entering the Arctic. By pumping low-salinity cold surface water across the dam to the Pacific, warmer and higher salinity sea water from the Atlantic Ocean would be introduced into the Arctic Ocean. However, citing national security concerns, the CIA and FBI experts opposed the Soviet plan by arguing that while the plan was feasible, it would compromise NORAD and thus the dam could be built at only an immense cost. Soviet scientist D. A. Drogaytsev also opposed the idea, stating that the sea north of the dam and north-flowing rivers in Siberia would become unnavigable year round, and the Gobi and other deserts would be extended to the northern Siberia coastline.