Yes, the Arctic blast that the much of the Country will experience this week is a sign of climate change. Although temporary freezing temperatures may be a convenient way for climate change-deniers to advance their beliefs, it is a well-known fact that climate change involves temporarily cooler temperatures alongside a general warming of the globe.
The Arctic blast, unusual for this time of year, indicates that climate change is in full force. Increased water temperatures melt ice caps, raising water levels and causing the atmosphere and weather to change, creating things like unseasonably cold and hot weather. Unnatural weather patterns indicate that our climate systems are changing, possibly irreversibly.
Science is actually at an all-time low for extreme climate events. Some people have graphed the number of hurricanes in recent years and found that they have been fewer and farther in between than in the past. Sometimes, there are just weather patterns. Sometimes there are changes in the jet stream. It's normal.
Climate is the observation of weather patterns over the course of many years. Thus, one "arctic blast" is not necessarily an indicator of climate change. It is not unusual for cold fronts to move through the country as this "arctic blast" has. In order for this to be a sign of climate change there would need to be sufficient proof of a progressive and multi-year trend of abnormally cold weather.