Ozone pollution reduces the growth of tropical forests and therefore the ability of these important carbon sinks to absorb CO2According to a study published on Thursday, September 12, in the journal Nature Geoscience.
Ozone (O3) present at low altitude is an atmospheric pollutant formed from the chemical transformations of nitrogen oxides (NOunknown) or volatile organic compounds, especially emitted by road traffic and industrial activities. This gas has a negative effect on human health but also on plants, particularly on their photosynthesis process and growth.
The international team of scientists who published the study sought to better quantify its influence on tropical forests, which until now was uncertain. To do so, they experimentally identified the reaction to ozone of ten tropical tree species before modeling the results. They conclude that “substantial decrease” of the net capacity of trees to absorb CO2.
“Ozone has prevented the capture of 290 million tons of carbon per year since 2000”
«We estimate that ozone has prevented the capture of 290 million tons of carbon per year since 2000. The resulting cumulative loss is equivalent to a 17% reduction in carbon uptake by tropical forests since the beginning of the century.»sums up Alexander Cheesman, one of the main authors of the study.
“It is clear that the impact of air pollution on tropical forests has played and continues to play a substantial role in the global carbon cycle.”the scientists conclude.
They predict that ozone concentrations will continue to increase in the tropics, also warning of the risks to reforestation projects in these regions.
“We found that current and future forest restoration areas, which are critical for climate change mitigation, are disproportionately affected by this high level of ozone.”“stresses Flossie Brown from the University of Exeter, who co-led the study.
Finally, the researchers highlight the benefits of reducing ozone formation through environmental measures, both for air quality and for carbon sinks.
