Mauna Loa CO2 (Keeling Curve)

Every month since 1958, scientists at a volcano observatory in Hawaii have measured how much CO2 is in the air. The measurements show a clear upward trend. You've probably seen the graph (called the Keeling Curve) that looks like a hockey stick with little ups and downs each year. Those wiggles happen because plants absorb more CO2 in Northern Hemisphere summer and release it in winter. But the overall slope keeps climbing. This is the single most important dataset proving that CO2 in our atmosphere is rising.

Source rows:

823

Coverage:

1958-01-01T00:00:00Z – 2026-12-31T00:00:00Z