Long description

This is a graph of the ‘Keeling Curve’ that shows the seasonal fluctuations. It shows over sixty years of measurements, from September 1957 through to February 2023, of the concentration of carbon dioxide in the atmosphere, and charts its rise from 315 parts per million at the start of the period to around 420 parts per million at the end. This trend has not been seasonally adjusted and the seasonal fluctuation can be clearly seen as a rise and fall in amplitude each year of about 5 parts per million. The seasonal peak occurs in late spring and the trough in autumn.