Throughout our lives, we have consistently heard about the significance of planting trees and their role in combating climate change. While it is true that trees have the capacity to absorb carbon dioxide (CO2), the scientific understanding of their role as carbon sinks and their significance in mitigating climate change has developed over time. The advancements in climate science, particularly in the 20th century, have helped improve our understanding of their complex interactions with CO2.
Through photosynthesis, trees actively CO2, a potent greenhouse gas, from the atmosphere and utilize it to fuel their growth. As trees mature, they continue to absorb CO2, incorporating it into their leaves, trunks, roots, and the surrounding soil, turning them into invaluable carbon sinks. 1
However indiscriminate deforestation worldwide has prevented this very ability of trees to act as carbon sinks from having a greater role. Tropical Rainforests store more than 210 gigatons of carbon and deforestation has resulted in an additional 15% of carbon emissions remaining in the air. Furthermore, approximately 13 million hectares of forests have been converted for other purposes or are lost due to natural causes.2 These alarming statistics have led researchers to highlight reforestation as a potential solution to combat the pressing issue of climate change. But is this the only solution? The answer to this seemingly simple question is more complex than you might think.
Firstly, trees grow very slowly. They will not start absorbing a meaningful amount of CO2 until they are at least 20-30 years old. Young trees are also vulnerable to droughts, storms, pests and diseases. Therefore, not only should we plant them but also nurture and protect them until they are mature.3
Secondly, we should ensure native trees suited to local conditions must be planted rather than prioritizing corporate or government-driven tree planting targets. Tree planting offers benefits beyond carbon sequestration. They contribute to biodiversity preservation, provide habitats for diverse species, and act as natural barriers against soil erosion, protecting valuable land and water sources. Therefore, planting of non-native tree species could negatively impact biodiversity and fail to restore the natural habitat effectively.4
Finally, since trees rely on respiration, they also emit a certain amount of CO2. There is a small but growing group of research that shows that trees also emit a diverse array of complex chemicals that contribute to warming the planet. It may come as a surprise to some, but recent research has shed light on tree emissions where volatile organic compounds (VOCs) emitted by trees can react with nitrogen oxides to form ozone, a potent greenhouse gas. Research so far has shown that every square meter draws in about 1,700g of CO2 every year - while also releasing up to 1,200g.5
So, how should we approach the planting of trees and reforestation efforts?
Implementing reforestation on a global scale has the potential to capture an astonishing 70 billion tons of carbon by 2050, equivalent to seven years' worth of current industrial emissions.6 However, a scientifically backed approach is necessary to ensure targeted and ecologically aligned reforestation efforts while prioritizing native tree species in the region.
For example, the Great Green Wall initiative in the Sahel-Sahara region aims to combat desertification and restore native plant life to the landscape by planting a mosaic of trees and shrubs across multiple countries. It addresses the underlying drivers of degradation by providing alternative income sources through sustainable land management practices. Local communities are involved in decision-making, ensuring that the chosen species are well-suited to the environment. The project focuses on restoring the entire ecosystem, promoting biodiversity, and balancing land uses between agriculture and afforestation.7
Tree planting and reforestation efforts carried out with these factors in mind is a potent long-term solution. However, it alone cannot solve the problem of climate change. It is crucial to halt all deforestation projects worldwide and preserve older forests with their diverse array of species.
Most importantly, we must reduce our dependence on fossil fuels. To align with a 1.5°C-consistent pathway, the global community needs to slash fossil fuel production annually by approximately 6% from 2020 to 2030 in order to see an effective change. Embracing sustainable energy alternatives is imperative for securing a livable planet for future generations.8
In order to harness the true power of trees to combat climate change, we need a paradigm shift in our approach. By acknowledging this, we can unlock the boundless potential of trees as catalysts for transformative change.
Weir K. Forest carbon 101. 2022. Available from: https://www.nature.org/en-us/magazine/magazine-articles/forest-carbon-101/
Deforestation facts and statistics. https://www.theworldcounts.com/stories/deforestation-facts-and-statistics.
Mark G. Anderson. Wild carbon, a synthesis of recent findings [Internet]. 2021 [cited 2023 Jul 21]. Available from:https://rewilding.org/wild-carbon-a-synthesis-of-recent-findings/.
Delang, Claudio. (2014). China’s Grain for Green Program: A Review of the Largest Ecological Restoration and Rural Development Program in the World.
G. Popkin. How much can forests fight climate change? Nature. Vol 565, doi:10.1038/d41586-019-00122-z
J-F. Bastin et al. The global tree restoration potential. Science. Vol. 365, July 5, 2019, p. 76. doi: 10.1126/science.aax0848.
United Nations Convention to Combat Desertification. Great Green Wall Initiative.https://www.unccd.int/our-work/ggwi
United Nations Environment Programme. https://news.un.org/en/story/2020/12/1079012
About Dr. Priyanka Lanka
Dr. Priyanka Lanka is an accomplished healthcare professional with a successful career in dentistry and a passion for studying the intersection of public health and climate change.
After getting her Bachelor of Dental Surgery degree, she went on to specialize in Prosthodontics and Implantology. She obtained her Master of Dental Surgery degree with distinction from Rajiv Gandhi University of Health Sciences in India.
In the summer of 2023, she worked with FXB USA as a Climate Change intern while pursuing her Master's in Public Health with a major in Global Health at New York University. She is also an active member of the Global Action for Urban Health lab at NYU.
In her spare time, she enjoys spending time with her toddler and is passionate about learning various Indian classical dance forms.