Mauna Loa Observatory is a station that measures elements in the atmosphere that contribute to climate change on Earth. They also measure elements that may deplete the ozone layer. This data is critical because the ozone layer protects us from harmful radiation produced by the sun’s ultraviolet rays.

Mauna Loa Observatory’s location marks an ideal spot for sampling Earth’s air. It is located in the U.S. state of Hawai‘i on the side of Mauna Loa, the world’s largest active volcano. The observatory is approximately 3,400 meters (11,141 feet) above sea level and remains a long distance away from significant pollution sources. This means the air is relatively clean, which makes it easier for scientists to study.

Scientists began studying the atmosphere at Mauna Loa in the 1950s. To detect any change in Earth’s climate, Mauna Loa measures different gases in the air. Some of the gases they measure include carbon monoxide, methane, nitrous oxide, and sulfur dioxide. Perhaps the most notable, though, is the observatory’s measurements of carbon dioxide (CO₂). The measurements are displayed in a graph known as the “Keeling Curve,” named after the late Dr. Charles David Keeling. He was a professor at Scripps Institution of Oceanography. He was the first researcher to report that the levels of CO₂ in the atmosphere were consistently rising on Earth. The curve describes the longest continuous record of CO₂ in Earth’s atmosphere.

Mauna Loa Observatory performs important work tracking Earth’s changing climate. The information gathered there helps scientists protect habitats and settlements on Earth.