Carbon cycle—nature’s crucial role in climate regulation

In a new video, SNAP Québec, Nature Québec and their partners in the Nature alliée project explain in a simple and informative way the crucial role our natural environments play in climate regulation. This video is part of a series raising public awareness about the importance of conservation in combating climate change while demonstrating how human disruption accelerates the release of carbon stored in vegetation and soils.

How do our ecosystems capture and store carbon?

Trees absorb carbon dioxide (CO₂) from the atmosphere through photosynthesis, a process in which they use sunlight to transform CO₂ from the atmosphere into oxygen and sugar. The tree then uses these sugars for growth, allowing the carbon that was present in the atmosphere to be stored in its trunk, branches and roots. What few people know is that, over time, forest carbon accumulates in very large quantities in soils. Carbon storage in soils is particularly important in colder environments, such as boreal forests, and also where decomposition is slower, such as peatlands and other wetlands.

By removing carbon from the atmosphere and storing it for decades or even centuries, natural environments act as a shield against climate change. The more time passes, the more they accumulate carbon and keep it out of the atmosphere. Sequestered in this way, carbon cannot contribute to climate change as when it is present in the air in the form of CO₂ or methane. Natural disturbances, such as fires, periodically release some of the carbon contained in trees into the atmosphere, but very little of the carbon contained in the soil. However, the re-emitted carbon is recaptured when young forests are regrown, in a balance that varies according to the global climate.

In Quebec, the vast forests and many wetlands have enabled several billion tonnes of carbon to be stored in vegetation and soils over the millennia. At the global level, the world’s forests store more carbon than all the fossil fuel deposits combined.1 While protecting these ecosystems helps to combat the climate crisis, disturbances in these environments lead to a reduction in sequestration or even the release of this carbon into the atmosphere, thus increasing the greenhouse effect.

Why does forest regeneration impact the carbon cycle?

Logging has drastically reduced the average age of forests in Quebec. Analyses of pre-industrial forests show that more than 60% to 75% of forests from the beginning of the last century were 100 or more years old.² Nearly a hundred years later, the last large swaths of boreal forest near the northern limit of logging cover less than 15% of the entire commercial forest.³ Because the process of storing carbon in vegetation and soils takes time, forest regeneration has an impact on the ability of forests to store carbon. Young forests, while growing faster, typically have lower carbon stocks than those of old-growth forests, which have accumulated carbon for decades, if not centuries.

It is therefore important to understand that logging is an activity that impacts the climate by disrupting forest carbon stocks, adding to natural disturbances and increasing the proportion of young forests. However, the more the climate changes, the more we see extreme events such as droughts and wildfires, which result in the release of carbon into the atmosphere. This is the snowball effect of climate change…

How can we find a balance?

Forestry and the wood it supplies can be used to replace other energy-intensive materials, such as concrete, thereby reducing GHG emissions from the construction sector. Forest protection provides an immediate and essential climate solution by protecting large existing carbon stocks and the associated biodiversity.

The challenge is to find a balance where forest management minimizes its climate footprint and conservation still allows sustainable economic activity in forest regions. The Nature alliée project is therefore working with several community partners to help reach the target of 30% protected areas while ensuring the sustainability of forest-dependent communities. Keep an eye out for the next Nature alliée videos!

¹  Pan, Y., Birdsey, R.A., Fang, J., Houghton, R., Kauppi, P.E., Kurz, W.A., Phillips, O.L., Shvidenko, A., et al. (2011). A large and persistent carbon sink in the world’s forests. Science 333, 988–993; Pan, Y., Birdsey, R.A., Phillips, O.L., Jackson, R.B. (2013). The structure, distribution, and biomass of the world’s forests. Annu. Rev. Ecol. Evol. Syst. 44, 593–622.
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Five Reasons the Earth’s Climate Depends on Forests https://web.archive.org/web/20250117174128/https://www.climateandlandusealliance.org/scientists-statement/
² Boucher, Y., Arseneault, D., Sirois, L. et al. Logging pattern and landscape changes over the last century at the boreal and deciduous forest transition in Eastern Canada. Landscape Ecol 24, 171–184 (2009). https://doi.org/10.1007/s10980-008-9294-8
³ Mackey, B.; Campbell, C.; Norman, P.; Hugh, S.; DellaSala, D.A.; Malcolm, J.R.; Desrochers, M.; Drapeau, P. Assessing the Cumulative Impacts of Forest Management on Forest Age Structure Development and Woodland Caribou Habitat in Boreal Landscapes: A Case Study from Two Canadian Provinces. Land 2024, 13, 6. https://doi.org/10.3390/land13010006