Chemical & Engineering News,
November 27, 1995

Carbon dioxide concentrations over the past 1,000 years determined from ice core records (shown as symbols) appear to have fluctuated little until 1850. Since 1958, air measurements (shown as purple line) taken at Mauna Loa, Hawaii, have supplemented the ice core data. The smooth black curve is based ona 100-year running mean. The inset of the period from 1850 onward shows CO2 emissions in gigatons (billions of metric tons) per year attributed to burning fossil fuels (shown as a blue line).

SOURCE: United Nations Intergovernmental Panel on Climate Change