The carbon cycle is a fascinating process. It turns sunlight into sugar and tissue. It transfers gases like oxygen and carbon dioxide from the atmosphere to plants—and back. Many autotrophs, like plants and phytoplankton, continue this exchange even in death. As plant matter decomposes, the stored carbon is released back into the atmosphere.
This process takes place largely at the microscopic level. But it occurs at such an enormous scale that it is visible from space.
This carbon exchange is asymmetric. The amount of carbon taken into an environment differs from the amount released through respiration. Scientists refer to this difference as net primary productivity. Net primary productivity is a measure of the increase in biomass in an area over time.
The Moderate Resolution Imaging Spectroradiometer (MODIS) instruments aboard the National Aeronautics and Space Administration’s (NASA) Aqua and Terra satellites provide one way we can measure an environment’s productivity. Rob Simmon and Reto Stöckli used MODIS data to map net primary productivity for NASA’s Earth Observatory. The maps above show how some regions, like the Amazon rainforest, have high net primary productivity year-round. Other areas, like North America, Eurasia, and sub-Saharan Africa, experience stronger seasonal change.
In addition to global and seasonal patterns, these maps demonstrate an uncommon clarity in their approach. Made in 2010, the maps rely on straightforward color cues (green for land, blue for water) and linear changes in value and saturation. With a design that draws on the way humans see and interpret color, these maps will remain intuitive for decades to come.
And that’s important. As our world and its climate changes, we can look to cartographers to bring clarity to conversations about Earth and its processes.
More to Explore
- Watch how carbon monoxide and carbon dioxide move across Earth.
- Learn more about biomass and energy.
- Interact with a gross primary productivity map from NASA (updated every eight days).
