Description
The authors developed a quantitative reconstruction of temperature changes over the past 3500 years based on alkenone distribution patterns in a sediment core retrieved from China's Lake Qinghai (37°N, 100°E), based on the alkenone unsaturation index that has been calibrated to the growth temperature of marine alkenone producers and "to temperature changes in lacustrine settings on a regional scale." This work revealed that the peak warmth of the Medieval Warm Period (AD 900-1500) exceeded the temperature of the latter part of the 20th century by about 0.5°C.