As a component of a multi-faceted strategy aimed at reducing the repercussions of greenhouse gas emissions, researchers aim to enhance their comprehension of the effects of increasing carbon dioxide (CO2) concentrations on terrestrial habitats, especially tropical forests. In pursuit of this goal, climate scientist César Terrer, the Class of 1958 Career Development Assistant Professor of Civil and Environmental Engineering (CEE) at MIT, alongside his colleague Josh Fisher from Chapman University, is applying their scientific insights in a distinctive environment — an active volcano in Costa Rica — to investigate carbon dioxide emissions and their impact.
Increased levels of CO2 can result in a phenomenon called the CO2 fertilization effect, whereby plants grow at a quicker rate and sequester more carbon, generating a cooling effect. Although this effect has the capability to serve as a natural moderator of climate change, the degree to which plants can perpetually absorb carbon remains ambiguous. There are rising apprehensions among scientists that plants may eventually hit a saturation point, compromising their capacity to mitigate the surge in atmospheric CO2. Grasping these dynamics is essential for precise climate forecasting and formulating strategies for carbon sequestration management. Here, Terrer elaborates on his groundbreaking methodology, his motivations for participating in the project, and the significance of promoting this research.
Q: What motivated you to pursue this area of research, and what distinguishes it?
A: Climate scientist and long-standing collaborator Josh Fisher had the ingenious idea to utilize naturally elevated CO2 levels found near active volcanoes to explore the fertilization effect under real-world circumstances. Conducting such investigations in dense tropical rainforests such as the Amazon — where the most significant uncertainties regarding CO2 fertilization exist — poses difficulties. It would necessitate sizable CO2 tanks and extensive infrastructure to evenly disseminate the gas throughout the towering trees and intricate canopy layers — an endeavor that is not only logistically daunting but also exceedingly expensive. Our method enables us to bypass these challenges and obtain crucial data in a manner that has not been previously attempted.
Looking for an expert in carbon ecology to co-lead and enhance this research, Josh found a perfect match in my background of understanding the mechanisms that govern carbon storage in terrestrial environments in the context of climate change. This area has been pivotal to my research and was the theme of my doctoral dissertation.
Our experiments within the Rincon de la Vieja National Park are particularly thrilling as CO2 levels in regions adjacent to the volcano are four times higher than the global mean. This provides us with a unique opportunity to observe the influence of heightened CO2 on plant biomass in a natural environment — an undertaking that has never been conducted at this scale.
Q: How are you assessing CO2 levels at the volcano?
A: We have deployed a network of 50 sensors throughout the forest canopy encircling the volcano. These sensors continuously track CO2 levels, enabling us to compare areas with naturally high CO2 emissions from the volcano to control regions with standard atmospheric CO2 levels. These Bluetooth-enabled sensors necessitate our close proximity for data retrieval. They will remain operational for an entire year, capturing a continuous dataset regarding CO2 fluctuations. Our upcoming data collection expedition is scheduled for March, with another planned a year following the initial setup.
Q: What are the long-term aspirations of this research?
A: Our main goal is to ascertain whether the CO2 fertilization effect can be perpetuated or if plants will eventually encounter a saturation threshold, constraining their carbon absorption capability. Recognizing this limit is vital for refining climate models and carbon mitigation approaches.
To broaden the extent of our measurements, we are investigating the implementation of aerial technologies — such as drones or sensors mounted on airplanes — to evaluate carbon storage across more extensive territories. This would yield a more thorough perspective on the carbon sequestration potential within tropical ecosystems. Ultimately, this research could provide vital insights regarding the prospective role of forests in combating climate change, aiding scientists and policymakers in developing more precise carbon accounting and climate forecasts. If successful, our methodology could pave the path for analogous studies in other ecosystems, enriching our understanding of nature’s response to escalating CO2 levels.