Is this a good argument for the existence of global warming?

I just came back from a trip to Yosemite. I was surprised to see large section of brown or cut-down trees. The damage was due to the bark beetle, which is a native species normally kept in control by a few cold days in winter. Link The sequoias and redwoods have not been affected, but the beetle is doing a number on the dominant ponderosa pines. Even those who ignore reports of ice melting in the Arctic might pay attention to changes closer to home.