Global Carbon Dioxide: 2020-2021

December 6, 2021
CreditNASA's Scientific Visualization Studio
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Dec. 6, 2021

This video shows the accumulation of atmospheric carbon dioxide (CO2) during a single calendar year. Every year, the world’s vegetation and ocean absorb about half of human-caused CO2 emissions, slowing the rate of greenhouse gases entering the atmosphere.

However, around 2.5 parts per million (ppm) remain in the atmosphere every year, causing a steady rise in concentrations that scientists have been tracking since the 1950s, at surface stations. (The term "parts per million" refers to the number of carbon dioxide molecules per million molecules of dry air.)

The visualization starts in June 2020, showing all of the model’s values of global CO2. (All 3D cells of the model are opaque, revealing a solid brick of data.) During this month, the higher values of CO2 coalesce around the "equatorial belt."

By mid-July 2020, CO2 values between 385 ppm and 405 ppm in the atmosphere become transparent. These lower values tend to be higher in the atmosphere. By visualizing the data like this, the higher CO2 concentrations, which are closer to the ground, are highlighted, revealing the seasonal movement of high CO2 at a global scale.

During the months of June to September (summer months in the Northern Hemisphere), global CO2 concentrations tend to be the lowest, because Northern Hemisphere plants actively absorb CO2 from the atmosphere via photosynthesis, which is the process of turning sunlight, carbon dioxide, and water into food (sugars) and oxygen. During Northern Hemisphere fall and winter months, much of the CO2 is re-released into the atmosphere, due to respiration, and can be seen building up.

By June and July 2021, plants again draw CO2 out of the atmosphere, but notably higher amounts remain there in contrast with the previous year. The daily rhythm of CO2 is apparent over our planet's largest forests, such as the Amazon rainforest in South America and the Congo rainforest in Central Africa.

The fast-paced pulse in those rainforests is due to the day-night CO2 cycle: Plants absorb the greenhouse gas during the day via photosynthesis (when the sun is out), and then stop absorbing it at night.

In addition to highlighting the buildup of atmospheric CO2, the video shows how interconnected the world’s greenhouse gas problem is. NASA’s unique combination of observations and models plays a critical role in helping scientists track CO2 increases to better understand their climate impact.

The visualization was created to support a series of talks from NASA scientists during the United Nations' 26th Conference of Parties (COP26), a climate change event that took place in Glasgow, U.K., from October 31 to November 12, 2021.

More information on this visualization: