What Are Carbon Offsets?

Written By Teacher: Liz Ransom

As a High School Spanish teacher and student newspaper advisor, Liz has taught for over 20 years and has served as World Languages Department Chair and K-6 summer camp activities leader. She has worked in Ohio, Maine, New Jersey, Maryland, and Chile.

Carbon offsets are often discussed as tools to move societies towards funding the transition to planet-friendly economies. But do they work? Students can practice critical thinking skills and engage with real-world issues by tackling this debate. Resources such as this video criticizing net-zero targets or this report on the “illusion” of green aviation will provide students with plenty of food for thought, while this lesson from MIT leads students to evaluate claims and data about carbon offsets. 

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.

Carbon offsets are tradable “rights” or certificates linked to activities that lower the amount of carbon dioxide (CO2) in the atmosphere. By buying these certificates, a person or group can fund projects that fight climate change, instead of taking actions to lower their own carbon emissions. In this way, the certificates “offset” the buyer’s CO2 emissions with an equal amount of CO2 reductions somewhere else.

How does buying carbon offsets keep CO2 out of the atmosphere?

Carbon offsets fund specific projects that either lower CO2 emissions, or “sequester” CO2, meaning they take some CO2 out of the atmosphere and store it. Some common examples of projects include reforestation, building renewable energy, carbon-storing agricultural practices, and waste and landfill management. Reforestation in particular is one of the most popular types of projects to produce carbon offsets. Carbon offsets are granted to project owners, who sell them to third parties like companies that want to balance the CO2 they put into the atmosphere by paying to remove CO2 from somewhere else.

Although carbon offsets are easy to understand, there are many challenges in producing them. To issue carbon offsets, a project needs to prove it will actually reduce emissions. The amount of CO2 being kept out of the atmosphere also needs to be accurately measured. This process requires well-documented standards and protocols, as well as a trusted way to verify that the project is doing everything it claims. These procedures can be expensive and specific to one type of project. But without them, we cannot trust that buying carbon offsets really lowers the amount of CO2 in the atmosphere.