What would happen if Yellowstone's 'supervolcano' exploded?

Can the 'supervolcano' underneath Yellowstone National Park wipe out the entire planet? Researchers have recently said it could erupt in the next few decades, which is a lot sooner than they thought. If this volcano does explode, it would be capable of expelling nearly 250 cubic miles of molten roc and ash with just one blast. Geologists believe the last time Yellowstone had a super eruption was some 631,000 years ago. According to CBS News, NASA has been making moves to lessen the blow and may unlock a new source of geothermal energy for use.