Regional Changes in Forest Carbon Storage

Which forests store the most carbon and how has that changed over the last thirty years? Forests are vital in the fight against climate change, absorbing large amounts of carbon dioxide (CO2) from the atmosphere. A recent study led by Yude Pan, a research scientist with the U.S. Department of Agriculture’s Forest Service, provides new insights into the role forests play in sequestering carbon over the past three decades.

Findings of the forest carbon study

For this study, researchers analyzed forest data from the past 30 years across different regions: boreal (northern), temperate, and tropical.

Global forest carbon storage rates have stayed consistent over the last three decades

They found that forests globally have been absorbing carbon consistently at a rate of about 3.6 billion tons per year in the 1990s and 2000s, and slightly less in the 2010s (3.5 billion tons per year). This carbon storage amount is nearly half of the CO2 emissions from fossil fuels during this period.

Forest types with increased carbon storage

However, there have been changes in carbon storage within different types of forests. Temperate and tropical regrowth forests have increased their carbon absorption due to growing forest areas. Temperate forests, particularly in China, have increased their carbon sinks by 30%, largely due to extensive reforestation efforts. In the United States, middle-aged forests continue to sequester carbon, despite disturbances from insects and fires.

Forest types with decreased carbon storage

On the other hand, boreal forests and intact tropical forests have seen a decrease in carbon absorption due to disturbances and loss of forest area.

For boreal forests, the decline in carbon storage has been 36% and for tropical forests, 31%. Temperate forests in regions like Europe and Japan have also experienced declines in carbon absorption as the forests age.

The researchers concluded that the benefit of the 3.5 billion tons per year global forest carbon sink has been significantly diminished by tropical deforestation. The study found that two-thirds of the carbon absorbed by forests—around 2.2 billion metric tons annually—was offset by deforestation in the tropics. 

The importance of forests for meeting emission reduction goals

The study’s findings underscore the critical importance of preserving and enhancing global forest carbon sinks. The significant offset caused by tropical deforestation highlights the challenges of achieving net-zero greenhouse gas emissions by 2050.

Reduced forest carbon sinks make it more difficult for nations to meet their emission reduction targets and increase the risk of climate-related disasters such as droughts, floods, and wildfires.

Policy Recommendations: Protecting and Enhancing Forest Carbon Sinks

To sustain and enhance forest carbon sinks, the study recommends several key policy actions:

1. Halting Deforestation and Degradation: Limiting deforestation is essential, not just in tropical regions but across all forest biomes. This will help maintain the carbon sequestration capacity of forests and prevent them from becoming carbon sources.
2. Promoting Forest Restoration: Reforestation and forest restoration, particularly on lands not needed for agriculture, can significantly enhance carbon sinks and contribute to climate change mitigation.
3. Improving Timber-Harvesting Practices: Sustainable logging practices are crucial to reducing emissions from timber harvesting and sawmill operations.

Forest carbon storage study

Pan, Y., Birdsey, R. A., Phillips, O. L., Houghton, R. A., Fang, J., Kauppi, P. E., … & Murdiyarso, D. (2024). The enduring world forest carbon sink. Nature, 631(8021), 563-569. DOI: 10.1038/s41586-024-07602-x

Fonte : National Geographic