Measuring a trace gas: How NASA tracks our planet's breath

Space · Published 11 October 2026 Swipe more like this →

In short: Concentrations of carbon dioxide typically reach merely a few hundred parts per million, making this wandering, hard-to-detect gas a mere trace component. Despite its minuscule concentration, it is the leading human-produced greenhouse gas. To understand our climate, scientists had to invent entirely new hardware just to see it from space.

The challenge of monitoring carbon dioxide (CO2) lies in its behavior as a building block for life. It does not stay in one place; instead, it moves constantly between the atmosphere, oceans, and land. Because CO2 is a trace gas—unlike dominant components like nitrogen or oxygen—measuring it accurately from orbit was initially met with skepticism. In 2003, some experts even scoffed at the idea that such a nomadic substance could be captured by satellite instruments. The mission's origins date back to a pivotal meeting in April 2003 at the California Institute for Technology. Scientists there faced the arduous task of designing instruments that simply did not exist at the time.

To overcome this, NASA developed the Orbiting Carbon Observatory-2 (OCO-2). Launched on July 1, 2014, from Vandenberg Air Force Base, OCO-2 became the first NASA spacecraft dedicated specifically to studying atmospheric CO2. It was built as part of the Earth System Science Pathfinder program, which prioritizes small, low-cost missions that deliver high-impact scientific value. This spacecraft was constructed by NASA's Jet Propulsion Laboratory in Pasadena, California. It serves as a primary tool to quantify carbon exchange between land and air.

Today, it is considered the gold standard for carbon dioxide measurements from space. Since its launch over a decade ago, OCO-2 has provided critical data on how shifts in rainfall alter vegetation's carbon storage and how ocean temperatures affect CO2 absorption. Beyond climate modeling, the mission has driven practical progress in crop-yield forecasting, drought early warning systems, and forest management. NASA continues to support this field by investing roughly $100 million annually into research programs that study the biological and physical processes of the global carbon cycle. The data also offers unexpected insights into general plant health and rangeland management. Furthermore, the agency has spent hundreds of millions of dollars on various tools like integrated datasets and computer modeling to solve this puzzle.

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