Fact Check: Moss Does Not Absorb More CO₂ Than Trees — Misleading Claim Explained with Scientific Evidence

As the world faces the growing threat of climate change, one of the most practical and effective strategies to slow global warming remains simple: planting trees. Trees play a critical role in reducing greenhouse gases—particularly carbon dioxide (CO₂)—by functioning as natural air filters. They absorb CO₂ from the atmosphere and store it in their trunks, branches, roots, and leaves, while releasing oxygen back into the air. Through the process of photosynthesis, trees and other green plants take in carbon dioxide to produce energy and build their own tissues. The carbon becomes locked in the plant’s structure and the surrounding soil, making trees valuable long-term carbon sinks. This natural storage of carbon not only helps clean the air but also contributes to climate stability.

Amid this, a few users shared pictures of moss with the text claiming that moss absorbs four times more CO₂ than trees worldwide.

Fact Check:

The claim is misleading. Certain mosses, in specific conditions, can absorb CO₂ efficiently, but overall, trees absorb and store much more carbon than moss.

While speaking with botany expert Upasana Panda, she clarified that mosses do absorb carbon dioxide (CO₂) from the atmosphere, but they generally do not absorb more CO₂ than trees on a per-plant basis. Some studies have indicated that certain moss species or moss-covered surfaces—such as forest floors or green roofs—can absorb considerable amounts of CO₂ per unit area. In specific conditions, their efficiency may be comparable to, or slightly higher than, some tree species. However, due to their small size, mosses store much less carbon overall compared to trees, which hold large amounts of carbon in their trunks, branches, and roots over long periods.

According to her, moss may absorb more CO₂ per kilogram of biomass, but the total carbon captured by trees far exceeds that of mosses because of their size and longer lifespan. The widely circulated claim that moss absorbs "four times more" CO₂ than trees, perhaps stems from lab-based findings or limited applications and should not be interpreted as a general fact.

She also noted that the claim does not hold true in all regions. In eastern Indian states such as Odisha, Bihar, Jharkhand, and parts of Chhattisgarh, moss growth is seasonal. It typically appears during the monsoon on damp walls or unpolished concrete surfaces. After the rainy season ends, moss largely disappears during the summer. Moss is usually found in areas where soil and water meet, such as near riverheads and streams. Therefore, such claims about moss absorbing more CO₂ are not applicable in these regions.

According to a study reported by Michigan News, researchers led by drylands ecologist David Eldridge from the University of New South Wales, Australia, and ecosystem ecologist Manuel Delgado-Baquerizo from the Instituto de Recursos Naturales y Agrobiología de Sevilla, Spain, found that mosses can store significant amounts of carbon in the soil beneath them. Among the co-authors is forest ecologist Peter Reich from the University of Michigan, who also serves as director of the Institute for Global Change Biology at the School for Environment and Sustainability.

The study estimated that mosses help sequester approximately 6.43 billion metric tons more carbon in the soil compared to nearby bare soil areas in global semi-arid regions. This amount is nearly six times greater than the annual global carbon emissions resulting from land-use changes such as deforestation, mining, or urban expansion.

The researchers also found that mosses cover over 3.6 million square miles (about 9.4 million square kilometres) of the Earth's surface, an area comparable to the size of Canada or China. This extensive coverage contributes to mosses’ influence on soil biodiversity and carbon storage.

However, it is important to note that the climate conditions in countries like Canada and China differ significantly from those in India. The environmental role and growth patterns of mosses in Indian regions—especially in eastern states—may not mirror those observed in colder or more temperate zones.

Hence, it proves the claim is misleading. Certain mosses, in specific conditions, can absorb CO₂ efficiently, but overall, trees absorb and store much more carbon than moss