Gas-guzzling SUVs are bad for the planet. But if you're a bark beetle, you might want to tip your antenna to the next Hummer you see. Aided by global warming [0], bark beetles are thriving in the Rocky Mountains - killing off millions of acres of pine trees that anchor entire ecosystems.

In parts of Wyoming and Montana, near Yellowstone National Park, between 60 and 100 percent of the trees have been decimated by bark beetles [1], turning lush pine forests into dry, dead fields of brown. In 2005, the beetles killed 1.2 million acres in the northern Rockies.

Scientists believe the beetle infestation - which has been growing every year for more than a decade - is aided by global warming, which has brought warmer winters. This means the bugs can thrive during the winter, instead of going dormant as they once did.

Extended periods of drought have also helped the beetles, weakening the trees and making them more vulnerable. And warming temperatures are allowing the beetles to head to higher elevations than ever before, threatening trees that are a prime food source for grizzly bears.

Experts say the forests will recover, but possibly not until the beetles run out of trees to infest. In British Columbia [2], where the problem is especially bad, research is underway to find commercial uses [3] for the beetle kill wood.

Image credit: West Arm Watershed Alliance [4]