The EPA & Heatwaves

By Paul Homewood

 

 

 

It is regularly claimed that climate change will lead to more heatwaves and unusually hot days. Interestingly, the EPA have a map which seems to disagree.

 

http://www.epa.gov/climatechange/science/indicators/weather-climate/high-low-temps.html

 

They explain the map as follows:-

 

 

This map shows trends in unusually hot temperatures at individual weather stations that have operated consistently since 1948. In this case, the term “unusually hot” refers to a daily maximum temperature that is hotter than the 95th percentile temperature during the 1948–2013 period. Thus, the maximum temperature on a particular day at a particular station would be considered “unusually hot” if it falls within the warmest 5 percent of measurements at that station during the 1948–2013 period. The map shows changes in the total number of days per year that were hotter than the 95th percentile. Red upward-pointing symbols show where these unusually hot days are becoming more common. Blue downward-pointing symbols show where unusually hot days are becoming less common.

 

To be clear, this cover all days of the year, and not just summer. Nevertheless, there seems little evidence, over the country as a whole, of any trend to more extreme hot days.

Even more significant, is the fact that they start their analysis from 1948, thus missing the hot 1910’s and 1930’s. Factor these years in and there would be a lot more blues, as the EPA’s Heat Wave index shows.

 

 

http://www.epa.gov/climatechange/science/indicators/weather-climate/high-low-temps.html

 

They show one further chart.

 

http://www.epa.gov/climatechange/science/indicators/weather-climate/high-low-temps.html

 

No guesses why they start in 1950!