Please answer a question about the following article about Crimean War:

Russia feared losing Russian America without compensation in some future conflict, especially to the British. While Alaska attracted little interest at the time, the population of nearby British Columbia started to increase rapidly a few years after hostilities ended. Therefore, the Russian emperor, Alexander II, decided to sell Alaska. In 1859 the Russians offered to sell the territory to the United States, hoping that its presence in the region would offset the plans of Russia's greatest regional rival, the United Kingdom.

What did the Russians fear losing without compensation?
British Columbia