Climate change fuels both California's record drought and "polar vortex" storms
Bonus hotspot chart
One of the least appreciated facts about global warming is that small changes in average global temperatures lead to large increases in extreme heat records. Studies of temperature records show this is already happening. As mentioned above, one recent paper showed that local monthly "hottest ever" records are five times as common as before. And a study by Dr. James Hansen two years ago showed that really extreme summer heat records are now 30 times more common than they were in the period from 1950-1980.
To illustrate how this trend toward increasing extreme heat played out this winter, I've included four months of NOAA temperature charts below. I've again removed everything but record hot and record cold areas.
As you can see, this winter was marked by large areas of all-time-record warmth. Particularly impressive in size and duration is the red blob off the west coast of North America discussed above. But it was hardly the only hotspot. For example, Africa (Jan), Europe (March), South America (Jan) and Mexico (Feb, March) also had areas of record warmth for that time of year.
When it comes to record-breaking cold however there is little to see. December had one spot in the Middle East. January had none. February had one spot in the mid-Atlantic. And March had the Great Lakes area.