The most likely scenario is: The proportion of white-furred rabbits in the population declines.
As the average temperature increases and winters become shorter, the environmental conditions may favor the brown-furred rabbits, which are better camouflaged against the changing landscape. White-furred rabbits may find it more difficult to survive and reproduce as their fur color becomes less advantageous, leading to a decline in their population relative to the brown-furred rabbits.