Several experts worldwide are warning against a new practice of “greenwashing.”
It is about promoting the use of algae to combat climate change, seeking to take advantage of its ability to absorb carbon dioxide during its growth, in order to limit this greenhouse gas.
However, academics such as biologist Alejandro Buschmann warn that this is a practice that has not yet been scientifically proven.
World cultivation
Buschmann explains that currently more than 97% of production (32 million tons annually) globally comes from aquaculture practices, and that Asian countries such as China, South Korea and Japan are leaders in the production of edible seaweed.
However, he adds that countries such as Indonesia, the Philippines, Malaysia, India and in recent years some African countries today produce a group of red algae through aquaculture practices for the production of polysaccharides, which go mainly to the meat products industry.
“Chile is one of the few countries in America and Europe that grow algae, but still in a very modest quantity (20 thousand tons per year), but we continue to be the country with the highest harvest level of annual algae populations with more than 500 thousand tons a year.”
The scientist highlighted that our country was a world pioneer in the cultivation of the red algae Gracilaria, also known as “pelillo” to obtain agar (another polysaccharide used in microbiology, and as a food additive), but starting in the 1990s In the 80’s its levels have fallen from 120 thousand tons to values that fluctuate at only 20 thousand tons annually.
Today this production is obtained mainly in the Los Lagos Region, but the regions of Coquimbo, Bío-Bío and los Ríos have also participated in this activity.
Ecological impact
When asked about the ecological impact of algae cultivation in Chile, the scientist states that today algae cultivation is carried out on a relatively small scale (20 thousand tons per year) and therefore its effects are not of any ecological relevance. However, he warns that like any human activity, aquaculture can have environmental risks.
“For example, if pests have to be controlled, one could think about using chemical products as is done in other aquaculture activities. “Algae as photosynthesizing organisms, like terrestrial plants, require inorganic nutrients, and therefore there is a risk that fertilizing the sea is something desirable by producers.”
In fact, it points out that there are already complaints in Southeast Asian countries where it is stated that activities such as those mentioned are carried out that compromise the environment. For this reason, he says, countries like Japan and South Korea have already prohibited these actions and “they are steps that we should consider in the short term to guarantee that algae cultivation is an environmentally sustainable activity.”
“On the other hand, if we plan to carry out these activities in places where there are urban effluents, from agronomic and livestock production or from the salmon aquaculture itself currently installed in Chile, we can maintain that their contributions in dissolved inorganic compounds such as ammonium, can be captured by algae and when we harvest these we extract these compounds from the water, we improve its quality again. This has been demonstrated in China in polluted environments where algae are grown in large areas (thousands of hectares), generating an improvement in water quality.”
Greenwashing
Regarding the practice of promoting algae cultivation to combat climate change, Buschmann is emphatic in pointing out that “this is a practice that does not exist today.”
“First, because the carbon credit market has not been implemented for use in algae grown in the sea. Second, data that demonstrate that this is feasible does not exist. There are some agencies that have promoted this idea, but without the necessary information,” he says.
“In addition, if we extract the algae and process it, we transform that organic matter back into CO2, reversing the CO2 capture process. For this reason, there are people who have imagined throwing this biomass into the deep ocean – thousands of meters away – but this would modify the flow of energy and matter in these ecosystems and therefore without information it does not seem ethical to promote this type of ideas.”
Efficient?
When asked if he believes that algae cultivation is effective in combating climate change, the specialist responds that “it is clear that to reduce the effects of climate change it is not enough to reduce our emissions to zero, because we have already introduced a number of greenhouse gases that will continue to be present in our atmosphere, unless we make a massive intervention by planting forests that should not be cut down for several centuries.”
“However, algae are not trees and do not accumulate carbon in their tissues for centuries, hopefully only for a couple of years. In other words, algae maintain the C2 cycle by not storing it in their tissues, because the algae dies. They do not by themselves help to reduce CO2 in the atmosphere. If we bury them or put them in the deep sea we may sequester CO2, but the consequences of this are unknown and again for this reason I do not believe it is ethical to promote these practices,” he warns.
He also states that there is an issue of scale for this to be significant at the level of climate change.
“We need to cultivate many millions of hectares with algae very intensively in the open ocean, which generates multiple challenges that no one has demonstrated their viability. And if this were technically possible, who pays to do this activity? Clearly, the value at which carbon credits are traded today does not allow paying for algae cultivation. Furthermore, with this amount of algae entering the market today, it would bring the prices that exist today to even lower values, which is not exactly an incentive to produce algae.”
Don’t fall into temptation
It is for these reasons among others that experts from around the world, including Buschmann, are calling not to fall into temptations by promoting tools that do not seem to be a solution.
“I could accept pilot studies to test concepts and verify the points where we currently have a knowledge deficit, but this is different from promoting initiatives that do not have a framework of minimal realism,” he says.
Finally, in the area of algae cultivation, what practice could be effective in combating climate change?
“Difficult answer since replanting forest will mean reducing the space for food production. It is feasible to manipulate chemical variables in the oceans so that they accumulate more CO than is currently in the atmosphere. Several other types of interventions have been thought of, but until now, at least in the oceans, I am unaware of any that one cannot really imagine strong side effects that we have not studied. From my point of view it is something that we still have to invent to really reduce the effects of climate change,” he concludes.
