Earth’s atmosphere now has more carbon dioxide in it than it has in millions — and possibly tens of millions — of years, according to data released Thursday by the National Oceanic and ...

Historical levels of climate change are determined by a number of processes. Samples of ice, lake and seafloor cores indicate how much carbon dioxide existed at different periods on the planet.

The Keeling Curve, a graph that plots concentrations of CO2 in the atmosphere over time, uses measurements taken at Mau Loa Observatory, starting in 1958.. In 2024, CO2 levels in Earth's ...