Albedo Fall Could Offset Climate Value of Forest-based Projects

Trees are well known for their ability to capture and store carbon, making reforestation and afforestation important strategies for mitigating climate change.

However, a new study published in Nature Communications warns that some forest-based carbon projects may unintentionally negate their own climate benefits due to the albedo effect, the measure of how much sunlight a surface reflects.

Dense, dark forests typically have a low albedo, meaning they absorb far more sunlight and heat than they reflect, which can contribute to warming.

Study examines 172 Global forest projects

The study, Accounting for albedo in carbon market protocols, was led by researchers from the Oregon State University College of Forestry, in collaboration with scientists at Clark University and The Nature Conservancy. It analysed 172 existing Afforestation, Reforestation, and Revegetation (ARR) projects across five continents, all supported by the Voluntary Carbon Market (VCM).

The VCM is a decentralised marketplace where businesses, organisations, and individuals can purchase carbon credits from forestry projects to offset their own emissions.

So far, carbon credits have focused solely on greenhouse gases, without accounting for non-greenhouse climate factors such as albedo. The authors argue that this gap means some projects may be overstating their climate benefits.

Forest-based climate mitigation efforts, therefore, must consider all climate-related impacts, not just carbon sequestration.

Key findings: Some projects lose climate benefits entirely

Among the 172 ARR projects studied:

• 12% are located in areas where albedo changes altogether cancel out the carbon benefits.
  
• Around 25% are in regions where albedo effects halve the benefits.
  
• Most projects are not significantly affected by albedo changes.
  
• 9% of projects occur in areas where albedo actually enhances climate benefits, making the surrounding landscape more reflective while also sequestering carbon.

These findings show that while many forest projects still deliver net climate benefits, a meaningful share may not be as effective as advertised when albedo is factored in.

Towards more accurate climate accounting

With recent scientific advances making albedo easier to measure, the authors propose a step-by-step method for integrating albedo into carbon credit assessments.

This would allow carbon markets to prioritise better projects that deliver genuine climate benefits and to quantify the credits used to offset carbon emissions more accurately.

The study also calls on researchers to develop tools to track other environmental changes, such as evapotranspiration, that are not currently accounted for in the Voluntary Carbon Market but may significantly influence climate outcomes.

Learn more about the study: Accounting for albedo in carbon market protocols.