Several independent indicators suggest that the climate of Alaska has warmed much more than the global mean over the last 1000 years (Whitfield, 2003). Warmer summers have led to a massive infestation of spruce bark beetles. The Columbia Glacier has retreated 12 km over the last 20 years and could completely collapse in another 10 years. Woody shrubs now grow where only spongy tundra existed just a few years ago. Whitfield (2003) asserts that "Alaska is warming up more than anywhere else on Earth."
Reference
Whitfield, J., 2003: Too hot to handle. Nature, 425, 338-339.