Ground Ozone Levels Impacting Carbon Dioxide Absorption by RainForests, Research Indicates Alarming Consequences
Ground Ozone Levels Impacting Carbon Dioxide Absorption by RainForests, Research Indicates Alarming Consequences
Ozone pollution is obstructing the growth of tropical forests and diminishing their carbon capture capabilities.
Ground-level ozone, which exists at lower altitudes, interferes with plants’ ability to absorb CO2. This form of ozone severely restricts annual growth in tropical forests, with Asian tropical forests experiencing a concerning 10.9% reduction in new growth each year.
While the ozone layer in the stratosphere is essential for shielding our planet from harmful ultraviolet rays, ground-level ozone presents a different challenge.
A recent study published in Nature Geoscience reveals that ground-level ozone significantly hampers the growth of tropical forests, resulting in an estimated annual shortfall of 290 million tonnes of carbon dioxide that goes unabsorbed.
Ground-level ozone is an invisible and irritating gas that forms near the Earth’s surface. It is classified as a “secondary” pollutant because it arises from the interaction of two primary pollutants in the presence of sunlight and stagnant air. The primary pollutants involved are nitrogen oxides (NOx) and volatile organic compounds (VOCs).
The reaction of these pollutants, driven by human activities and sunlight, leads to the creation of low-lying ozone, which not only disrupts plants’ ability to absorb carbon dioxide but also poses health risks to humans.
Researchers have carried out experiments to assess the responses of various tropical tree species to ozone, integrating their findings into a global vegetation computer model. The data indicates that ground-level ozone diminishes annual growth in tropical forests by an average of 5.1%. Since 2000, ozone has hindered the absorption of 290 million tonnes of carbon each year, resulting in a 17% decrease in carbon sequestration by tropical forests this century.
This effect is particularly pronounced in certain regions, with Asian tropical forests experiencing a concerning 10.9% drop in new growth.
The study reveals that areas designated for current and future forest restoration are notably affected by elevated ozone levels. Additionally, the insights gained from this research highlight the complex interplay between air pollution and climate change mitigation, stressing the need for comprehensive strategies that address both issues simultaneously to protect and enhance the vital carbon-sequestering functions of tropical forests.
Dr. Flossie Brown, co-lead author and graduate from the University of Exeter, notes that “ozone concentrations across the tropics are expected to increase further due to rising precursor emissions and changes in atmospheric chemistry in a warming world.”
