VIZAG: A new study published in the journal Weather has revealed that the natural sequestration of carbon dioxide (CO2) by the Earth’s biosphere is declining, leading to a faster rise in atmospheric CO2 concentrations. The research, “Natural sequestration of carbon dioxide is in decline: climate change will accelerate,” highlights that sequestration rates peaked in 2008 and have been decreasing at a rate of 0.25% per year.
According to the findings, if the biosphere had maintained its CO2 absorption capacity from the 1960s, the current atmospheric CO2 increase of 2.5 parts per million (ppm) per year would have been limited to 1.9 ppm. This decline weakens the planet’s ability to offset emissions naturally, making climate change progress more rapidly than previously estimated. The study emphasises the urgent need to restore biodiversity and ecosystem health to counteract this trend.
Researchers analysed long-term data from the Keeling Curve, which tracks atmospheric CO2 levels at the Mauna Loa Observatory in Hawaii. The seasonal fluctuation in CO2 levels, primarily driven by plant growth in the Northern Hemisphere, was found to have decreased after peaking in 2008.
Earlier studies had suggested a peak around 2006, but new data confirms that the decline has continued over the past decade.
The study attributes this drop in sequestration efficiency to multiple climate-related stressors, including wildfires, droughts, heatwaves, and the thawing of permafrost, which releases stored CO2 back into the atmosphere. Although a warming climate initially led to increased plant growth in some regions, the researchers note that soil nutrient limitations and ecosystem degradation are now outweighing these benefits.
Comparing historical trends, the study found that between 1958 and 1982, global CO2 emissions increased by a factor of 2.5, while atmospheric CO2 levels rose by only 2.31 times, indicating a growing capacity of natural sequestration. However, this trend reversed in recent years. Between 2000 and 2024, emissions grew by 1.48 times, while atmospheric CO2 rose by a factor of 1.51, confirming the weakening role of natural sequestration.
The study warns that without immediate action to restore ecosystems, the biosphere’s ability to absorb carbon will continue to deteriorate, further intensifying the impacts of climate change. The scientists called for urgent conservation efforts to rebuild biodiversity and enhance nature’s role in regulating atmospheric carbon levels.