Updated: Sep 25, 2020
Trees and forests are able to act as sinks by capturing greenhouse gases in the atmosphere and storing them in their roots and soil. By preserving our forests and reforesting where necessary, we can actively combat global warming. This is what we do at Climate Coping, where every purchase you make in our Green Shop preserves and plants trees that in turn will protect you.
TLDR: Trees and forests are great carbon sinks that we can protect and plant to combat climate change. However, this must be done in a reasoned way, consistent with a systemic and sound ecological transition.
The incredible absorption power of forests
Forests cover 31% of the earth's land surface and are, behind the oceans, the 2nd largest carbon sink on the planet. Forest ecosystems recycle carbon and as such play a major ecological role in the global balance. Throughout their lives, thanks to the biological mechanism of photosynthesis, trees draw carbon dioxide from the atmosphere. They store it in their trunks, branches, roots and leaves and then release oxygen into the air. This is called photosynthesis, a mechanism that allows us to both breathe and decrease the concentration of CO2 in the atmosphere.
The annual carbon absorption capacity of French forests is estimated at 70 million tons of CO2 equivalent, i.e. 15% of France's stored greenhouse gas emissions. As an example, a 5 m3 tree can absorb the equivalent of 5 tons of CO2. This corresponds to the emissions of 5 return flights between Paris and New York.
Carbon in forests is found not only in living biomass (plants, leaves, trunks, roots), but also in dead biomass on the ground (litter, snags, etc.) and in the soil. The stock of carbon retained by the living matter of the forest thus amounts to 8 billion tons of CO2 equivalent, making the forest the 2nd largest carbon sink on the planet, just behind the oceans.
Trillions of trees to save the world
Trees are our best weapon in the fight against climate change, thanks to their capacity to store CO2. Swiss researchers have calculated the number of trees that could be added to the planet and estimated that they could reduce the level of CO2 in the atmosphere by 25%.
In a study published in Science, they made the calculation: 1,200 billion trees are needed. That's 900 million hectares of forest, which would be added to the current 2.8 billion hectares.
Without humans, there would be 5,800 billion trees on Earth. We have reduced this number by half, so there are only about 3,000 billion trees today. So there are 2,800 billion trees missing. But it is impossible to replant them all as there isn't enough space left. In fact, the missing land is occupied by agriculture or urban areas.
But there is room for 1,200 billion trees. And the good news is that this is enough to absorb almost two-thirds of the 300 Gt of carbon emitted into the atmosphere by humans since the 19th century. It remains to be seen where to plant all these trees. To make their calculation, the two scientists analyzed the current forests as well as the climate and soil that could accommodate future ones. Half of the reforested areas are concentrated in six countries: Russia, the United States, Canada, Australia, Brazil and China.
Protecting our last primary forests
An international study published in Nature shows that just like young forests, old-growth forests can also store carbon. They must therefore be taken into account in the balance sheets and above all be better protected.
The primary forest can be defined as a forest of native species whose ecological processes have not been significantly disturbed. Primary rainforests, or tropical rainforests, are the terrestrial systems with the greatest diversity of species.
According to the new database compiled from measurements made by the "CarboEurope" and "AmeriFlux" observatory networks, old-growth forests continue to accumulate carbon. The database established for this study reveals that these old-growth forests sequester between 0.8 and 1.8 billion tonnes of carbon per year, and that 15% of the total forest area so far ignored in carbon budgets is responsible for at least 10% of total carbon sequestration.
Currently, more than 30% of the total forest area is primary forest not managed by man, half of which is in temperate regions of the Northern Hemisphere. For the authors of the study it is therefore obvious that these old-growth forests need to be included in carbon budgets and taken into account in the framework of the Kyoto Protocol. The international negotiations to follow up the protocol are already seeking to give greater value to the protection of forests in the fight against climate change. The results of this study are one more argument in favour of these initiatives.
Not all ecosystems are equal
Ecosystems are more or less efficient at storing carbon. For example, coastal wetlands such as mangroves, salt marshes and coastal grasslands are by far the most efficient. These ecosystems concentrate ten times more carbon than tropical forests or other marine ecosystems, such as coral reefs or phytoplankton!
Each year, these coastal environments store around 200 million tons of carbon, equivalent to the emissions of 150 million individual cars. By what miracle? Because they build up plant matter, like forests, but the difference - enormous - is that bacteria do not then decompose this matter, because of the presence of salt water. Soils gradually become huge piles of plant fragments, incredibly rich in carbon.
It is therefore essential not to drain these ecosystems in order to grow crops or build hotels, which is too often done, stresses the researcher, because not only does this stop this formidable storage of "blue carbon", but it also returns to the atmosphere what was incorporated into the soil.
Sustainable transition is not optional
Protecting and restoring our forests is important to preserve our environment, but it should not be an excuse for not reducing our carbon emissions. The ecological transition must be a priority before planting trees.
The ecological transition is an evolution towards a new economic and social model, a model of sustainable development that renews our ways of consuming, producing, working and living together to meet the major environmental challenges of climate change, resource scarcity, the accelerated loss of biodiversity and the multiplication of environmental health risks.
To follow this transition, we offer products in the Green Shop to help you make the transition to more sustainable practices, while preserving and planting trees for you. This way you both reduce your emissions and offset your remaining carbon footprint.