By Climate Central
Despite the current cold snap, 2016 is still on pace to be the second warmest year on record in the U.S. This temperature imbalance is illustrated in the ratio of record highs to record lows. In a stable climate, the long-term ratio should be in balance, or around 1-to-1, but that has not been the case for a long time.
In 2016, the number of record highs has dwarfed the number of record lows. This was most remarkable in November, when there were 48 record highs for every record low. Of all the daily temperature records set or tied last month, 98 percent of them were record highs.
For the year-to-date, record highs have outpaced record lows by 6-to-1. Each season has seen more record highs than record lows this year. For ratios, we have rounded to the nearest tenth.
- Winter (includes Dec 2015): 11.7 to 1 (92 percent of records set were record highs)
- Spring: 4.2 to 1 (81 percent of records set were record highs)
- Summer: 4.0 to 1 (80 percent of records set were record highs)
- Fall: 15.2 to 1 (94 percent of records set were record highs)
In the long term, the ratio of record highs to record lows has increased every decade since the 1970s, the last decade the record lows outnumbered record highs. We’re more than halfway through the 2010s, and record highs are outpacing lows more than 2-to-1.
As warming continues from the increasing amount of greenhouse gases in the atmosphere, that ratio will likely continue to rise. According to recent research, a 3°C (5.4°F) increase in the global temperature could increase that ratio to 7-to-1, or perhaps as much as 23-to-1. With no change in the rate of greenhouse gas emissions, we could warm that much in just 50 years. That much warming will make it unlikely that our children and grandchildren will experience what we think of as extreme cold today. Conversely, future generations will endure a level of summer heat more intense than any we’re currently used to.