Is Amazon Responsible for 20% of Earth’s Oxygen?

Q: Does the Amazon produce 20% of the world’s oxygen?
A: No. Scientists estimate the percentage is closer to 6 to 9%, and the Amazon ultimately consumes nearly all of that oxygen itself.

Debunking the Myth

The recent wildfires in the Amazon rainforest have brought attention to a popular but misleading factoid that the Amazon produces 20% of the world’s oxygen. However, scientists have revealed that this number is far too high. In reality, the Amazon is estimated to contribute approximately 6 to 9% of the planet’s oxygen. Moreover, the Amazon consumes most of the oxygen it produces, diminishing its significance as a major oxygen source for humans.

The Role of the Amazon

Contrary to popular belief, the Amazon isn’t critical for generating oxygen for human breath. Phytoplankton in the ocean has played a more significant role in oxygen production over millions of years. Rather, the Amazon’s importance lies in its rich biodiversity, vast carbon stores, and its influence on local and global climates.

More Accurate Estimates

Some scientists have offered their own calculations to provide a more accurate oxygen production estimate. Environmental scientist Jonathan Foley suggests that the Amazon contributes around 6% or less of the planet’s oxygen, while ecologist Yadvinder Malhi suggests a slightly higher figure of 9%. Both estimates are within the range of uncertainty for this calculation.

Understanding Photosynthesis

Photosynthesis, the process by which plants and organisms convert carbon dioxide into carbohydrates and release oxygen, determines the amount of oxygen produced. Tropical forests, including the Amazon, account for approximately a quarter to a little more than a third of photosynthesis on land. Given that the Amazon comprises about half or less of all tropical forests, it accounts for roughly 12 to 16% of all land photosynthesis. When considering photosynthesis from both land and ocean, the Amazon contributes only about 6 to 9% of the world’s oxygen.

Oxygen Consumption in the Amazon

Although the exact percentage may vary, it is important to note that the Amazon, like any ecosystem, predominantly consumes the oxygen it produces. Plants, including trees, use oxygen during respiration, similar to humans. Additionally, microorganisms in the Amazon’s ecosystem further consume about half of the region’s oxygen as they decompose various organic matter. Consequently, the net contribution of the Amazonian ecosystem to the world’s oxygen level is effectively zero.

Oxygen Origins on Earth

The majority of Earth’s oxygen can be traced back to ancient plants and photosynthetic organisms that died under specific conditions. Through preservation, a small portion of their photosynthetic material avoided decomposition and eventually transformed into oil, gas, and coal. These geological processes, mainly taking place underwater or in peat bogs, account for only a tiny surplus of oxygen and contribute to maintaining the current atmospheric oxygen level of approximately 21%.

Oxygen Supply and Preservation

Claims suggesting that the destruction of tropical rainforests like the Amazon would deplete the Earth’s oxygen levels are unfounded. Even if substantial areas of the Amazon were to burn, resulting in a slight decrease in oxygen levels, there would be no significant risk to humans. The current level of oxygen in our atmosphere is extensive, and any minute changes caused by burning fossil fuels are inconsequential. It would take millions of years for the Amazon or any other ecosystem to meaningfully deplete the world’s oxygen supply.

Protecting the Amazon

Although the Amazon’s production of oxygen for human consumption is minimal, it is crucial to protect this unique ecosystem. The Amazon’s remarkable biodiversity, vital role in regulating the climate, and vast carbon storage make it invaluable to our planet. From preserving genetic diversity to sustaining local water supplies and limiting climate change, the Amazon’s protection is necessary for various ecological reasons. It is essential to rely on accurate information and scientific evidence to guide our efforts in safeguarding this irreplaceable natural treasure.

Sources:

• de Oliveira Andrade, R., Andreoni, M., McCarthy, K., Yeung, J., Van Hagen, I. (2019). Alarming surge in Amazon fires prompts global outcry. Nature News.
• Tardáguila, C. (2019). Madonna, Leonardo DiCaprio, Cristiano Ronaldo and Emmanuel Macron didn’t fact-check before posting images about the Amazon fires. Poynter.
• Brienen, R. J. W., et al. (2015). Long-term decline of the Amazon carbon sink. Nature.
• Schwartz, J. (2019). Wallace Broecker, 87, Dies; Sounded Early Warning on Climate Change. New York Times.
• Brannen, P. (2019). The Amazon Is Not Earth’s Lungs. The Atlantic.