The UN, NOAA and the EPA in their analyses made the following claims:
Widespread changes in extreme temperatures have been observed in the last 50 years. Globally, cold days, cold nights, and frost have become less frequent, while hot days, hot nights, and heat waves have become more frequent.
Severe heat waves are projected to intensify in magnitude and duration over the portions of the U.S. where these events already occur, with potential increases in mortality and morbidity, especially among the elderly, young and frail.
There is no indication that record heat is increasing in frequency, in fact the data shows a precipitous decline in the number of heat records in recent decades. The early 20th century dominates the heat statistics for the United States and the world.
The presumption that global heat waves and extremes have increased in frequency is not supported by the official government data. NOAA’s NCDC shows that record high temperature by continent have occurred mainly in the 1880s and early 1900s, with only 1 post 1950 (Antarctica in 1974).
In the United States, there has been almost a total absence of new statewide records. There was no evidence of extreme warming based on temperature extremes. This analysis using NOAA data was compiled by InfoPlease through 2004 and updated with NOAA record page.