Global Warming Linked to More Extreme Weather

In a recent article for Climate Progress by Joe Romm, a growing number of extreme weather events in the past few years such as hurricane Sandy, droughts, heat waves, and changes to the jet stream are discussed. This more extreme weather is supposedly linked to the weakening of the jet stream. Research done in early 2015 by Jennifer Francis and Stephan Vavrus concludes that unrestricted greenhouse gas emissions and prolonged atmospheric conditions are linked to a global climate change. Their study states, "These results reinforce the hypothesis that a rapidly warming Arctic promotes amplified jet-stream trajectories, which are known to favor persistent weather patterns and a higher likelihood of extreme weather events.” Based on these results they conclude “…As a result of unabated increases in greenhouse gas emissions,” contributions, “to an increasingly wavy character in the upper-level winds, and consequently, an increase in extreme weather events will rise from prolonged atmospheric conditions." 

According to this article and the research it cites, extreme weather events have been increasing since the 1980s. Events that are geophysical, meteorological, hydrological, and climatological have been on the rise. A large number of weather extremes are a strong indicator of climate change. The evidence is cyclical. Climate change is feeding extreme weather events and in turn, these events are feeding climate change in a positive feedback loop. 

http://thinkprogress.org/climate/2015/01/15/3612054/global-warming-extreme-weather/