By Climate Central
As the planet continues to warm from the increase in greenhouse gases in the atmosphere, the temperatures that we consider to be normal are also rising. What younger generations consider very warm today may seem especially hot to their grandparents.
New temperature normals
NOAA publishes climatological normals every decade based on 30-year average temperatures; the most recent normals are based on the average temperatures from 1981-2010. Expanding on this dataset, Climate Central calculated a 30-year average ending each year from 1980 to 2015. For example, the normal temperature for 1980 in this analysis was based on the average temperature from 1951-1980, and the 2015 normal is the average from 1986-2015.
Of the 135 locations analyzed, 97 percent of them had a higher 30-year average temperature in 2015 versus 1980, and many have seen an additional surge in their normals since the last NOAA analysis in 1981-2010. The shift in long term averages has already become apparent in the longer growing season in most of the country, with temperatures starting to remain consistently above freezing earlier in the year, and staying above freezing until later in the year. Some plant and animal species are starting to migrate northward or upward in elevation as a result, meaning a variety of pests and weeds are now found in places previously too cold for them to live.
While the warming of the normals can look subtle, it also means a substantial increase in the incidents of extreme heat and a decrease in the frequency of extreme cold. Winters have been warming more rapidly than summers, and while less extreme cold sounds appealing, the future effects of blistering summer heat are expected to outweigh the benefits of milder winters. More extreme heat will increase the threat of heat-related illness such as heat stroke. In addition, this expansion of very hot days will stress the nation’s aging electric grid, driving up cooling costs as air conditioners will likely be used more frequently.