Another new paper published in Earth and Planetary Science Letters casts further doubt on the paradigm that says CO2 has historically been a temperature driver.
Evidence from southern California’s Lake Elsinore indicates today’s regional temperatures (18°C) are 4-5°C colder than a millennial-scale period between 29,000 to 26,000 years ago (29 to 26 ka), or during the last glacial.
At the time, temperatures reached amplitudes of 22-23°C while CO2 concentrations lingered around 200 ppm, or less than half today’s values.
During both the periods between 31 and 24 ka and 14 to 9 ka, temperatures also were found to have abruptly risen (and fallen) by more than 10°C within centuries. These temperature swings occurred with little or no change in the CO2 concentration.