Image caption
Changes in the amount of greenhouse gases in the air over the span of the modern scientific record: carbon dioxide (left), methane (center), and nitrous oxide (right). All three of these primary greenhouse gases reached new record-high amounts in 2021. The increase in methane was the largest annual increase on record. NOAA Climate.gov image, adapted from Figure 2.50 in State of the Climate in 2021. Background photo from NASA Gateway to Astronaut Photography of Earth.