The protagonists of compensation, part I

Faced with a world that suffocates and heats up with greenhouse gases, we think that today more than ever it is important to know the solutions that exist to transform our reality. One of these is forests: that group of vegetation that inhabited our planet millions of years before our arrival and that is - not just a break - but a solution to many of our problems. Plants in general have a property contrary to human properties: they are capable of capturing carbon dioxide in their tissues and soils, which means that they are great heroes who are fighting against the climate crisis offset, that is, to sequester, these polluting gases that we humans decide to emit excessively into the atmosphere -causing a global crisis- and store them in their bodies for a large amount of time.

The carbon capture that occurs in forests results from a universe of situations that range from the very biology of these organisms and their need to absorb atmospheric carbon to grow and survive, to purely anthropocentric scenarios such as the growing and innovative carbon market, determining the price and quality of the compensation that this vegetation performs and the additionality that this generates for humans and other biodiversity in the world. Let's dive a little deeper into this space of concepts, challenges and solutions, so revolutionary that it offers us -once again- a breath of clean air to face the climate crisis.

Toroto: How do forests sequester carbon? What happens to trees? How do they “inhale” carbon dioxide (CO2) and “breathe out” oxygen?

Skylight: It could be said, quite simply, that plants breathe the opposite of animals. We inhale oxygen, use it to produce energy, and as a result we exhale carbon dioxide. Instead, plants “breathe” carbon dioxide and, through photosynthesis, they use this molecule to produce carbohydrates, which are their main source of energy. Carbohydrates are composed of different elements that plants obtain from both soil and water through root uptake, but their only source of carbon is the carbon dioxide they capture from the air. They do this through a small structure found mostly in the leaves called “stoma” that is responsible for carrying out gas exchange: inhaling carbon dioxide, exhaling oxygen. Plant growth is directly related to the production of carbohydrates and, therefore, to carbon sequestration. When we talk about trees, this is translated into the production of lignin, which is the main component of wood. If we look at the macro level, the growth of a forest involves the capture of many tons of carbon dioxide and its transformation into wood. However, it's not just plants that produce wood that capture carbon dioxide.

T: Can any forest sequester carbon? Are other types of vegetation just as efficient at sequestering carbon?

L: All forests capture carbon, but not all forests capture the same amount or at the same rate. This makes more sense when compared to the growth of a human being: a child grows a lot, while an adult no longer grows. Thus, young forests tend to capture a greater amount of carbon dioxide than mature forests. Of course, this doesn't detract from the value of an old forest, because all that mature wood represents tons of carbon already captured that isn't in the atmosphere. It is important to mention that, just as they capture carbon dioxide, forests also release a certain amount of this gas mainly related to the decomposition of organic matter that the ecosystem is unable to reintegrate. However, a balance in a healthy forest is always positive, that is, it always captures much more than it releases. This is a good indicator to know if something is not in balance or working properly in the ecosystem. With respect to other types of vegetation, yes. There are ecosystems that promote carbon capture not only in the wood of trees, but also in the soil, as is the case of mangroves. A mangrove forest can have more carbon captured in the soil than in the wood. Something similar happens with the tundra, which is one of the most efficient ecosystems to capture carbon, however, unlike the mangrove, we don't have tundra in Mexico.

T: What does managing a forest sustainably entail for a carbon sequestration project? How long is the project viable?

L: Sometimes, the objective of carbon capture projects is to ensure the future growth of forests that are under significant pressure from land use change. In others, it is that the forest can capture carbon at a faster rate than it would have without the project. This can be done through ecological restoration, which seeks remove sources of disturbances that negatively impact forest health and resilience so that it can reach a successive state prior to the disturbance, and therefore, continue with its natural growth. It may be that, for example, uncontrolled grazing prevents natural regeneration and there are no young trees. If it is possible to exclude livestock from these areas, seedlings will be established from the same seed bank that is already there, and over the years young forest cover will increase, promoting the natural cycle of growth, death and regeneration that characterizes life and, in the same way, carbon capture.

However, for this to happen in a sustainable way, a socioeconomic component must invariably be included, since practically all Mexican territory has an owner, as a result of the land redistribution that occurred with the Agrarian Reform. If the restoration of a forest does not represent a tangible benefit for the owners of the land, but rather an impediment to improving their quality of life, the project is not viable. The trick, and the most complex part, is to find the perfect combination of practices that represents benefits for all parties involved and that the project triggers a virtuous circle rather than a vicious one. In the concrete example of grazing, it is important to find a way for the project to also benefit farmers, who will need to compensate for the food excluded from their animals' diets. If a component of grazing management, capacity building and alternative food production is included, it is much more feasible for these people to join the main objective, which is to recover the health of the forest and capture carbon as a result. We have examples of great impact, such as silvopastoral management systems.

As long as all the actors involved benefit in a transparent and fair manner, the project will have a long life because it will be in the interest of all parties that it does not end. In this regard, it is important to indicate the ideal duration of a carbon capture project, which is related to the average time that a carbon dioxide molecule stays in the atmosphere causing global warming. This time is 100 years, therefore, this is the duration for a project on private property; when implemented on social property (i.e., ejidos or indigenous communities), the maximum allowed by the Agrarian Law in Mexico is 30 years, which can be extended year after year as long as the owners of the land so wish and see fit. However, whether they are 100 or 30 years old, the important thing is that the processes that involve carbon capture in natural ecosystems occur in the long term, so carbon capture projects must extend as long as possible over time, otherwise they make no sense.

T: What is the problem that puts forests and their role as carbon sinks most at risk?

L: Definitely the thing that puts forests at greatest risk is land use change. This may have different reasons for being, depending on the area. For Mexico: on the outskirts of cities, it is the growth of urban sprawl; in the south, it is the explosion of extensive livestock farming. The decrease in forest cover not only means that there are fewer forests, but it also impacts the remaining vegetation, that is, that little bit of native vegetation that we still have left, and its connectivity and dynamics with other forest areas. The decrease in forest cover is related to the increase in temperature and the fact that rains behave in an increasingly erratic way, aggravating droughts and stressing the ecosystem that is still standing. In fact, according to a study published in the journal Nature Highly resounding at the end of last year, this vicious cycle may result in forests emitting more carbon dioxide than they capture.

T: How do you measure carbon capture in a forest? Who checks it? Are there any international regulations or regulations that are responsible for this?

L: Carbon capture in a forest can be determined by measuring tree growth. By measuring the diameter at chest height, the total height, the height of the crown and identifying the species, the volume and density of the wood that the tree contains can be known, and this can be translated into tons of equivalent carbon dioxide (TCO2e). This unit is the same one used to measure the pollution of a company, becoming an effective tool that allows us to compare the pollution that is generated with the capture of carbon, that is, the amount of that pollution that is sequestered and, therefore, compensated. Fortunately, it is not necessary to measure all the trees in the forest, since through statistical processes, sampling sites are selected whose measurement is representative for the entire project area.

It is important to emphasize that not all the wood in a forest can be translated into carbon credits, since plant growth prior to the start of the project cannot be counted as bonds because it already existed; it is not additional. The capture of carbon that can be converted into bonds begins when the owners of the land decide to implement the project and the baseline measurement is carried out, which is the study that will indicate how much carbon there was at the beginning. From here on, all of the growth represents bonds. However, there are different international protocols that serve to certify that baseline measurements and bond production estimates are not over or underestimated, which is very important because these projects must be as close to science and reality as possible. The two most used protocols in Mexico are those of the California Climate Action Reserve (CAR) and Verra.

(End of interview, find part II hither)

The carbon market is constantly growing and always adapting to the needs and requirements of our - also changing - planet. Part of this dynamism has generated biases and interesting challenges to be solved by virtue of building a stronger, more resilient, but above all, fair market. What are these challenges and how to solve them? We invite you to find the answer in part two of this interview, which we will publish very soon.

About the interviewee: Lucero works in Toronto as Senior Center Operations Manager. He studied a degree in Biology and a master's degree in Sustainability Sciences at the UNAM. What he likes most about nature is the diversity of life forms that exist and the relationship that different cultures have created with them. In his spare time he enjoys seeing his friends and visiting outdoor places.