Even with regional perturbations of deforestation and wildfires, the world’s forests stand as a stalwart companion to humans in the fight against climate change. As shown by a breakthrough study published on 18 July 2024 in Nature, these vital ecosystems have been quietly but steadily soaking up carbon dioxide over the last three decades while various kinds of disturbances threatened to turn off their carbon sequestration function.
A study entitled “The Enduring World Forest Carbon Sink” reinforces exactly this critical role of forests against climate change. The researchers represent evidence for the fact that forests have been absorbing an average of 3.5 ± 0.4 billion metric tons per year, approximately half of the CO2 emissions through fossil fuel burning from 1990 to 2019.
The lead authors were Yude Pan, a senior research scientist with the USDA Forest Service Northern Research Station, and Richard Birdsey of the Woodwell Climate Research Center, a senior scientist. Eleven countries contributed to the 15 co-authors. Their results paint a picture that’s nuanced in regional variations of forests’ ability to serve as carbon sinks.
It is estimated that there has been a massive 36% decline in the carbon sink capacity of boreal forests in the Northern Hemisphere, encompassing Alaska, parts of Canada, and Russia. This is said to be because of rising aggravations emanated by wildfires and insect outbreaks together with rising soil warming. There is also a decline of 31% in the capacity to absorb carbon due to deforestation in tropical forests. However, regrowth in abandoned agricultural lands and logged areas has offset part of these losses, keeping the tropics close to a net carbon flux near zero.
In contrast, temperate forests have increased their carbon sink capacity by 30%, a development that was more than expected, due to large-scale reforestation, especially in China. According to Dr. Pan, this study was different because of the extensive ground measurements in terms of size, species, and biomass for every single tree. Other than remote sensing data, this research was based on detailed on-the-ground data collection.
The persistence of the global forest carbon sink was a surprise, given global increases in wildfire, drought, logging, and other stressors,” says Dr. Birdsey. He further explains that net emissions from places with increased emissions were balanced by an increase in accumulation from others. This happened dominantly due to re-growing tropical forests and reforestation of temperate forests. The findings support the potential for improving the protection and management of forests as effective natural climate solutions.
It also details how some of the land management policies and practices may offer benefits in safeguarding this global carbon sink. The authors argue for reducing deforestation over all forest biomes; restoration of lands that are inappropriate for agriculture; and better timber harvesting practices as a way to reduce emissions from logging and associated activities.
The findings, however, also show that data collection, especially in the tropics, is low. The study has called for an increase in research and the establishment of more ground sampling plots in these areas to cut down uncertainties in carbon estimates and improve the understanding of the global carbon budget.
Forests play a critical part in fighting climate change. Protection and restoration of the ecosystems of these forests are indispensable for mitigating climate impacts and achieving greenhouse gas reduction targets.