So what made it so hot when atmospheric CO2 was at or below 300 ppm?
Climate Central reports:
A brutal and potentially historic heat wave is in store for the West as parts of Nevada, Arizona and California may get dangerously hot temperatures this weekend and into next week. In fact, by the end of the heat wave, we may see a record tied or broken for the hottest temperature ever recorded on Earth…
ll-time records are likely to be threatened in normally hot places — including Death Valley, Calif., which holds the record for the highest reliably recorded air temperature on earth at 134°F. That mark was set on July 10, 1913, and with forecast highs between 126°F to 129°F this weekend, that record could be threatened. The last time Death Valley recorded a temperature at or above 130°F was in 1913.