New research published in the journal Nature Geoscience predicts that Earth’s oxygen-rich atmosphere could last just over a billion years.
As the Sun ages, it becomes brighter and brighter, which means that in the future the Earth will receive more energy. The increased energy will affect the surface of the planet, increasing the wear and tear of silicate rocks such as basalt and granite. The above rocks are abrasive, causing carbon dioxide to be removed from the atmosphere and through a chemical reaction in the carbonate-containing minerals. In theory, the Earth should start to cool as carbon dioxide levels decrease, but over the next 2 billion years, this effect should decrease due to the increasingly intense light from the Sun.
Carbon dioxide, along with water, is one of the main elements that plants need for photosynthesis. Under conditions of reduced carbon dioxide, photosynthesis will take place less and some plants may die. Less photosynthetic plants lead to reduced oxygen production. Gradually, the concentration of oxygen in the Earth’s atmosphere will decrease, causing a crisis for other forms of life.
To find out when this is happening, researchers in Japan and the United States are using computer simulations to model the future evolution of carbon, oxygen, phosphorus and sulfur cycles on the Earth’s surface. They also looked at how the climate is changing and how the Earth’s surface (crust, oceans, and atmosphere) interacts with its interior (mantle).
The team modeled two scenarios: an Earth-like planet with an active biosphere and a planet without an active biosphere. Both situations give the same result. Oxygen levels begin to drop sharply over the next billion years. The results show that although the reduction in carbon dioxide and photosynthesis affects oxygen levels, the effect of the process is secondary to the interaction between the mantle and the surface environment.
The study’s team of authors concluded that oxygen-rich air may only exist for another 1.08 billion years. Oxygen began to accumulate in the Earth’s atmosphere 2.5 billion years ago. It is likely that oxygen levels have been relatively low for most of the planet’s history, barely reaching current levels until after the Earth’s Crop Revolution about 400 million years ago. Researchers estimate the total habitable time on Earth before dehydration. However, the oxygen-rich environment only lasts about 20-30% of that time.
