In the fight against climate change, trees are considered to be the star of the show because they can remove greenhouse gases from the atmosphere. However, reforestation alone is not enough to offset the planet-warming emissions. More sophisticated nature-based alternatives are also emerging. For some scientists, tackling the massive challenge of climate change starts with something small: algae.
Microscopic heroes
Algae are a diverse group of aquatic organisms. Like many plants, they are autotrophs. They can capture carbon dioxide and convert it into oxygen and food. Despite their small stature, the swarm of algae in the ocean compensates for their size.
“They are the organisms to count on against climate change,” Dr. Emelina Mandia, a professor from the Department of Biology remarks. Just one-tenth of a hectare of algae can sequester more than what a hectare of trees can. Mandia expounds that this is due to the disparity between the density of algal organisms compared to trees within a small area.
Another advantage that algae have over trees is their growth rate. They can double their biomass within a day, allowing them to capture carbon at a faster rate. Though, this advantage is also a double-edged sword because they require routine harvesting and optimum conditions to prevent overgrowth. Trees, on the other hand, require minimal maintenance once they have been planted, but it takes them a long time to reach their full potential to sequester carbon.
Untapped potential
Algae can be classified into macroalgae and microalgae. The former refers to multicellular organisms that are visible to the naked eye. They exhibit a range of colors, such as green (Chlorophyta), red (Rhodophyta), and brown (Phaeophyceae) algae. Conversely, microalgae can only be seen under a microscope. The archipelagic nature of the Philippines fosters the cultivation of algae and the proliferation of algal farms. In 2018, local production of seaweed, a macroalgae, reached 1.48 million tons, accounting for almost five percent of the total global production that year. The Bureau of Fisheries and Aquatic Resources also reported in 2022 that 200,000 families had been engaged in seaweed production, mainly due to the practice’s low cost and sustainability. Despite the many economic prospects of algal cultivation for the country, the climate mitigation ability of algae has not been of primary relevance in the development of the industry to date. Mandia still believes that its economic and environmental functions can coexist with each other.
Currently, microalgae have only been extensively explored as a source of biofuel. Dr. Aristotle Ubando, associate dean for Research and Advanced Studies of the Gokongwei College of Engineering, is at the forefront of local microalgal and biorefinery research. Ubando has recently explored sustainable pathways to algal biofuel production due to the currently high costs that it entails.
Outside of the laboratory, people are also finding ways to utilize the environmental and economic benefits of algae cultivation. An algal farm in Muntinlupa City harvests green microalgae or Chlorella vulgaris, a known height booster, and sells them for P3,000 per kilogram. Apart from that, algae is also used in the production of cosmetics, fertilizers, and nutritional supplements.
The limitations of nature
While trees and algae prove to be effective carbon absorbers, they are not a long-term solution to the current climate crisis. They need to be grown on a large scale to have a significant impact on global carbon levels. However, as these organisms take up more land and aquatic resources, they could potentially disrupt the natural balance of the ecosystem.
Moreover, there is a limit on how much carbon trees and algae can capture. Various environmental research have found that once these organisms have reached their saturation point, their ability to absorb carbon diminishes. The constant burning of fossil fuels further undermines the efforts made through nature-based solutions. Government organizations also declared that cultivating algae or trees will prove to be a futile endeavor if more carbon is produced than the amount they could capture.
It is tempting to rely on tree-planting programs and algal farms to save the planet. Although they are still beneficial, there is ultimately no miraculous solution to a problem as complex as climate change. Instead of cutting corners, people need to adopt multiple approaches to reduce their carbon emissions, such as having an eco-friendly lifestyle, pushing for laws that promote renewable energy sources, and demanding accountability from various industries.
This article was published in The LaSallian‘s January 2025 issue. To read more, visit bit.ly/TLSJanuary2025.
