By Kenneth Richard During the 1930s, when the atmospheric CO2 concentration was about 100 ppm lower than today (310 ppm vs. 410 ppm), United States heat waves were just as if not more common than recent decades. Recently there has been much ado about heat waves and the hottest-ever-recorded-temperatures making their rounds in Northern Hemisphere … Continue reading US Instrumental Records Indicate More Heat Waves Occurred In the 1930s Than Today