In the end, climate change will mean the planet will be warmer - but on these cold December NJ days, it's worth noting that right now we will probably be getting more cold, wet and snowy weather.
According to the Weather Underground, last winter a natural climate pattern known as the North Atlantic Oscillation (NAO) was at the most extreme negative side since record keeping began in 1865.
The high pressure replacing low pressure over the Arctic had only been this extreme for 4 winters in the past 160 years—1969, 1963, 1936, and 1881.
The NAO is one of oldest known climate oscillations. Seafaring Scandinavians described the pattern several centuries ago. Negative NAO winters tend to bring cold winters to Europe and the U.S. East Coast, but leads to very warm conditions in the Arctic, since all the cold air spilling out of the Arctic gets replaced by warm air flowing poleward.
Other factors include the El Niño/La Niña cycle and natural oscillations in stratospheric winds.