How Much CO₂ Do Plants Absorb?

Written By Teacher: Elaine Makarevich

Elaine is a New Jersey educator with 30 years of teaching experience in grades K-6. The earth and the natural world have always been a focus of her life and throughout her career as her students learned critical lessons about their planet when visiting her indoor or outdoor classrooms.

Understanding how much carbon dioxide (CO₂) plants absorb is key to teaching students about the carbon cycle and climate change. Plants remove CO₂ from the atmosphere through photosynthesis, helping to regulate global temperatures. However, with rising CO₂ levels, scientists are studying how effectively plants can keep up. This MIT article explores how increased plant growth affects CO₂ absorption.

To help students engage with this topic, here are resources for different grade levels:

• Elementary:  Cycle of Matter and Energy Transfer in Ecosystems – This video explains how plants absorb CO₂ through photosynthesis and how energy moves through ecosystems.
• Middle School: Trees from Thin Air - This activity explores how trees store carbon and helps students calculate how much CO₂ they absorb.
• High School: Photosynthesis Drives Change in Atmospheric CO₂ – A hands-on experiment where students collect and analyze data on how photosynthesis impacts CO₂ These resources provide engaging ways to help students understand the critical role plants play in balancing CO₂ levels.

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.

Plants are a natural “carbon sink”: as they grow, plants use sunlight to convert water and carbon dioxide (CO2) into sugar, effectively storing carbon in their tissues. This process helps regulate our planet’s temperature by taking climate-warming CO2 out of the atmosphere.

But this “land carbon sink” is actually a recent change for our planet. Before the Industrial Revolution, humans enjoyed a stable period for the Earth’s climate when plants and soils captured about as much carbon as they released. It’s the extra CO2 in the air today—from human activities like burning fossil fuels—that has boosted the rate of photosynthesis and let plants take up more carbon, which they use to grow faster and use water more efficiently.