Record daily high and low temperatures happen now and then at a give weather station. In a normal, stable climate the number of record highs and record lows should be about even. But with human-caused global warming, record highs are expected to be more common than record lows. And they are.
Climate Nexus has this handy dandy widget to track record highs and record lows over the previous year.
Click to see the 1950s, when global warming was not as severe at it is today. Then look at the 1990s when things were starting to take off. Then look at the last year.
Here is NCAR’s Gerry Meehl talking about the record record highs.
Thanks to Climate Nexus for putting this together.
Atmospheric temperatures still swing between “cold” and “hot” years, even as they now trend warmer on average. This is because of natural variation in the climate system, as heat cycles between the atmosphere and the ocean through phenomena such as El Niño. Heat records are more likely to be broken when natural variation runs in the same direction as global warming. When the two are out of sync, it is more likely that temperatures will be average or even a little below average. Therefore, the rising trend in the ratio of record highs to record lows is clearest when looking over decades.
The image at the top of the post is from UCAR.