Greta Stacy is a high school science teacher in Doha, Qatar. She has previously taught in Ecuador and the United States.
This topic is important to teach because it connects to the carbon cycle, a core idea in biology classes. The concept of carbon sinks, mainly the ocean and plants, is key to understanding this question. This lesson engages students with hands-on data gathering to understand the role of forests as carbon sinks. Students can further this discussion to include coastal and ocean sinks using this article.
Written By: MIT Environmental Solutions Initiative
The MIT Climate Change Engagement Program, a part of MIT Climate HQ, provides the public with nonpartisan, easy-to-understand, and scientifically-grounded information on climate change and its solutions.
When scientists give estimates for how long carbon dioxide (CO2) lasts in the atmosphere, those estimates are often intentionally vague, ranging anywhere from hundreds to thousands of years. The reason for the murky timeline is that CO2 molecules, once they enter the air, follow different paths and can last for radically different amounts of time.
Unlike some other atmospheric gases, CO2 mostly does not break down into smaller molecules while in the atmosphere. Methane, for instance—another important greenhouse gas—reacts with oxygen to turn into CO2 and water within a matter of years, and that process can be observed and measured. But CO2 molecules typically linger until something absorbs them from the air. Some are quickly taken up by the ocean, plants, and soil. Other atmospheric carbon sticks around for generations.
