Does this explain some of the extreme weather the world has been suffering?

Wonderful discovery. I doubt that it is unique to our era. The main thing that makes extreme weather sensational is the instant media network. It has always happened, but now we see it everywhere immediately.

It's the same type of drought that happened back in the 1870s in China where 9,000,000 people died due to drought conditions. The problem with people like Baccheus explaining this off as part of a human contribution to atmospheric changes is that recent scientific information has closely surveyed our atmosphere for only a short time. A warmist/alarmist has to find a reason to perpetuate propaganda. There is a claim that more climate extremes are happening like hurricanes and tornadoes and are more frequent. The problem with having more extreme hurricanes and many more tornadoes is that, if we are having them, then the atmosphere (troposphere) is cooling. What makes a hurricane or a tornado more intense is that the troposphere is much cooler than the surface temperature. The greenhouse gas theory proposes that the troposphere is warming faster than the surface temperature. Any climate scientist knows this.

What this study does is to better explain the mechanism. That the warming of the arctic has made the jet stream "wavier" has been known for several years. That has been explained on YA multiple times in the past. This is the new climate behavior that links climate change to the size and destruction of storm Sandy, or at least makes conditions more likely (ie actually had never been observed before in the Seaboard) that increase the likelihood of such a super storm. It is also the behavior that makes blizzards more likely as far south as Arizona and Florida, even as droughts also become more frequent in the heartland.

The jet stream has become slower, more prone to stalling and creating long-lasting killer heat-waves (eg in Europe in 2003, Russia in 2010, Midwest in 2012) and wavier which creates more frequent winter cold snaps far to the south (Florida in 2010, Arizona 2013).

This is a typical procession in scientific discovery. Researchers discover an association or make an observation. Later research better defines how the process works, what is causing it. Without the latter, the initial observations are more likely to be errant or random.

The claim "Extreme weather isn't caused by global warming" is denier myth number 24 on Skepticalscience dot com a useful site which keeps a list of the more common denier claims and debunks each and every one of them.

We haven't been having extreme weather, if you check weather statistics you will find our weather is no more extreme now than it ever was.

What we have now is extreme weather Reporting, the media always wants sensationalize everything.