FactSentinel

The claim that rainforests, particularly the Amazon, produce most of the world's breathable oxygen is a persistent myth that doesn't hold up under scientific scrutiny. In reality, the majority of the planet's atmospheric oxygen is produced by marine phytoplankton, algae, and other oceanic organisms, which are estimated to generate somewhere between 50 and 80 percent of Earth's oxygen through photosynthesis. Rainforests, while ecologically vital, contribute a much smaller share to the global oxygen supply.

The key reasoning behind this comes down to net oxygen production. Although rainforests do produce enormous amounts of oxygen through photosynthesis, they also consume nearly equivalent amounts through respiration, decomposition, and the natural life cycle of plant matter. Trees, soil microbes, and decomposing organic material all use oxygen as they break down, meaning that mature forests like the Amazon are roughly carbon and oxygen neutral over time. The oxygen released by growing trees is largely offset by the oxygen consumed as dead vegetation decomposes.

A common misconception fuels this myth: the Amazon is often called the "lungs of the Earth," which conflates its role in carbon storage and biodiversity with oxygen production. While the Amazon is critically important for absorbing carbon dioxide, regulating regional and global climate, and sustaining countless species, its net contribution to atmospheric oxygen is minimal compared to ocean-based organisms. Rainforest conservation remains essential, but not because it is the primary source of breathable air.