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 Hawaii 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.


Mauna Loa Observatory

The observatory on top of Mauna Loa in Hawaii, United States of America.


layers of gases surrounding a planet or other celestial body.

carbon dioxide

greenhouse gas produced by animals during respiration and used by plants during photosynthesis. Carbon dioxide is also the byproduct of burning fossil fuels.

carbon monoxide

colorless, odorless, and tasteless gas that is slightly less dense than air. It can be toxic to humans.

Charles Keeling

(1928-2005) American scientist who confirmed the accumulation of CO2 in the atmosphere.


to use up.


chemical that cannot be separated into simpler substances.


environment where an organism lives throughout the year or for shorter periods of time.

Keeling curve

graph illustrating the amount of carbon dioxide (CO2) in Earth’s atmosphere as measured at the Mauna Loa Observatory in Hawaii.


chemical compound that is the basic ingredient of natural gas.

nitrous oxide

greenhouse gas used in medicine and the manufacture of rockets. Also known as laughing gas or happy gas.


form of oxygen that absorbs ultraviolet radiation.


energy, emitted as waves or particles, radiating outward from a source.


community or village.

sulfur dioxide

greenhouse gas that can cause acid rain.


having to do with light of short wavelengths, invisible to the human eye.