The mean temperature deviations recorded since 1967 are graphed in red. They clearly indicate a definite warming trend over 43 years. The snowfall amounts (in blue), however, don’t correlate at all with the temperatures.
Climate change means an increase in extreme weather events like recent superstorm Sandy, as well as extreme temperatures on both high and low ends. A week of frigid temperatures from the Great Plains to the Northeast doesn’t contradict the warming trend of the planet. Writing in the Guardian, Blogger Harry J Enten warns that
It’s important to remember that the last few days are a very small location and sample size. While the east is a tundra, Denver, Colorado is dealing with near-record highs with temperatures in the 60s. When we expand our look to over the past month, record high maximums and minimums are running 2 to 1 ahead of record low maximums and minimums in the United States. The United States’ average temperature in 2012 was 55.3F – 3.2F above the 20th-century average and 1F above the previous record, 1998.
Weather patterns have very many variables, which makes them incredibly complex. It’s the trends that are telling, much more than individual events.