Periodic Reporting for period 1 - DISEQ (The Drought Impact on the Climate Benefit of Carbon Sequestration)
Período documentado: 2023-10-01 hasta 2025-10-31
Human activities have led to rising levels of carbon dioxide in the atmosphere, altering how carbon moves through the Earth’s systems and profoundly affecting the global climate. This shift changes the delicate balance between carbon, water, and energy that regulates both the atmosphere and ecosystems. While forests and soils naturally absorb large amounts of carbon from the air, it is still uncertain how much they can help slow down climate change by storing more of this carbon. Their ability to do so depends on the availability of water, sunlight, and nutrients that sustain key processes like plant growth, soil decomposition, and respiration—all of which operate over different time scales. Climate models predict that many regions will become drier in the future, especially the Mediterranean region, where droughts already occur frequently. Drought limits plant photosynthesis because trees and other vegetation close their leaf pores to prevent water loss, which also restricts carbon uptake. Yet scientists still do not fully understand how these dry conditions affect how long carbon remains in forests before returning to the atmosphere. This uncertainty makes it difficult to predict how effective forests will be as carbon sinks in the coming decades. Understanding these dynamics is crucial for improving our response to global warming.
To tackle this challenge, researchers have introduced a new approach that links two important concepts: Carbon Transit Time and Carbon Sequestration rate. The first refers to how long it takes for a carbon atom to travel through an ecosystem—from the time it is assimilated during photosynthesis until it is released back into the atmosphere through respiration. The second measures how much carbon a forest keeps stored over a given period. Together, these concepts provide a clearer picture of how ecosystems contribute to mitigating climate change.
Building on this idea, the DISEQ project is working to better understand how carbon is stored and moves across different time scales, with a particular focus on Mediterranean forests and the role of soil water in shaping those dynamics. The project explores three central questions:
How do global carbon storage processes vary when time scales are considered?
How does carbon move through different parts of a Mediterranean forest?
How sensitive are these carbon processes to drought?
To answer these questions, DISEQ combines global modeling, field sampling, and radiocarbon analysis (which helps trace how long carbon stays in the system). The project’s objectives are to:
Estimate global Carbon Sequestration using GPP and respiration data from diverse global datasets, including Earth System Models (ESMs), Dynamic Global Vegetation Models (DGVMs), and atmospheric inversion models.
Identify how carbon moves and is stored in different components of Mediterranean forests, such as leaves, soil, and wood.
Build a process-based model that simulates carbon cycling in Mediterranean forests under drought conditions.
By linking experimental data, laboratory measurements, and advanced models, DISEQ is improving scientific understanding of how ecosystems help regulate the climate. The new model will also be able to estimate how much global warming is avoided thanks to carbon stored by Mediterranean forests, even under challenging climate scenarios. On a broader scale, the methods developed will help assess the climate benefits of ecological restoration projects and guide future restoration planning.
In practical terms, this research provides valuable insights for policymaking and forest management in the face of climate change, particularly in Catalonia. The results directly contribute to the region’s 2030 Agenda and the United Nations Sustainable Development Goals (SDGs), including promoting climate action (SDG 13), conserving ecosystems and biodiversity (SDG 15), and ensuring sustainable living environments (SDG 11).
To tackle this challenge, researchers have introduced a new approach that links two important concepts: Carbon Transit Time and Carbon Sequestration rate. The first refers to how long it takes for a carbon atom to travel through an ecosystem—from the time it is assimilated during photosynthesis until it is released back into the atmosphere through respiration. The second measures how much carbon a forest keeps stored over a given period. Together, these concepts provide a clearer picture of how ecosystems contribute to mitigating climate change.
Building on this idea, the DISEQ project is working to better understand how carbon is stored and moves across different time scales, with a particular focus on Mediterranean forests and the role of soil water in shaping those dynamics. The project explores three central questions:
How do global carbon storage processes vary when time scales are considered?
How does carbon move through different parts of a Mediterranean forest?
How sensitive are these carbon processes to drought?
To answer these questions, DISEQ combines global modeling, field sampling, and radiocarbon analysis (which helps trace how long carbon stays in the system). The project’s objectives are to:
Estimate global Carbon Sequestration using GPP and respiration data from diverse global datasets, including Earth System Models (ESMs), Dynamic Global Vegetation Models (DGVMs), and atmospheric inversion models.
Identify how carbon moves and is stored in different components of Mediterranean forests, such as leaves, soil, and wood.
Build a process-based model that simulates carbon cycling in Mediterranean forests under drought conditions.
By linking experimental data, laboratory measurements, and advanced models, DISEQ is improving scientific understanding of how ecosystems help regulate the climate. The new model will also be able to estimate how much global warming is avoided thanks to carbon stored by Mediterranean forests, even under challenging climate scenarios. On a broader scale, the methods developed will help assess the climate benefits of ecological restoration projects and guide future restoration planning.
In practical terms, this research provides valuable insights for policymaking and forest management in the face of climate change, particularly in Catalonia. The results directly contribute to the region’s 2030 Agenda and the United Nations Sustainable Development Goals (SDGs), including promoting climate action (SDG 13), conserving ecosystems and biodiversity (SDG 15), and ensuring sustainable living environments (SDG 11).
The project’s main activities can be grouped into six key areas:
1. Literature review: From the start, we continuously reviewed scientific literature to guide decisions and shape the project’s direction. This helped connect our results with existing scientific knowledge and ensured that our interpretations were well-grounded.
2. Fieldwork: We carried out a one-week field campaign in the Prades Mountains, a forested area in Catalonia (northeastern Spain) where a long-term drought experiment has been running for decades. Before heading out, we transported sampling equipment from the Max Planck Institute for Biogeochemistry (MPI-BGC) in Germany. In the field, we collected air samples from soil and ecosystem respiration, along with solid samples of leaves, litter, wood, and soils from different depths. Samples were taken from both drought-treated and control plots.
Achievements: About 250 samples were collected, representing all main parts of a Mediterranean forest under both dry and natural conditions.
3. Laboratory work: I spent two months at MPI-BGC processing the collected material for radiocarbon analysis and performing soil incubations to obtain root-free soil respiration samples. The processing involved drying, sieving, grinding, and weighing samples to determine their carbon content, as well as extracting carbon from gases collected in the field and from soil incubations.
Achievements: Approximately 250 samples were successfully prepared and analyzed at the MPI-BGC 14C laboratory, providing detailed radiocarbon signatures for each forest component.
4. Data analysis: Data analysis took place in several stages to address different research goals. For the Mediterranean forest, we analyzed 25 years of drought experiment data to identify long-term patterns and trends. The radiocarbon results were then examined using statistical methods and discussed with experts, including a collaborative visit to Lawrence Livermore National Laboratory (LLNL) in Livermore, CA, to work with K. McFarlane, a specialist in ecological radiocarbon applications.
At a global scale, we analyzed data from multiple models—ranging from CMIP6 and TRENDY climate simulations to atmospheric inversion products including CAMS and CarboScope, and X-BASE—to assess how carbon sequestration has varied across the planet over time.
Achievements: We characterized how carbon moves and is stored in different parts of a Mediterranean forest and quantified how much carbon ecosystems worldwide have captured historically, revealing differences among models and regions.
5. Modelling: Using field and laboratory data, we developed a new model that simulates how carbon flows through a Mediterranean forest and how long it stays in each part of the ecosystem. At the same time, we created a method to combine results from multiple Earth System Models (ESMs) into a single, more reliable ensemble estimate.
Achievements: A model that represents carbon transit time and cycling in Mediterranean forests, plus a new technique for ensembling data from global climate models.
6. Advancing future opportunities: Beyond research, I also worked to secure future career and funding opportunities. I applied to postdoctoral programs such as Beatriu de Pinós and La Caixa Junior Leader (2024 edition and the latest round, which is still pending). I also successfully earned a competitive two-year research position at CREAF to prepare a European Research Council (ERC) proposal.
Achievements: Strengthened experience in scientific proposal writing, secured continued funding, and laid the groundwork for building my own independent research group.
1. Literature review: From the start, we continuously reviewed scientific literature to guide decisions and shape the project’s direction. This helped connect our results with existing scientific knowledge and ensured that our interpretations were well-grounded.
2. Fieldwork: We carried out a one-week field campaign in the Prades Mountains, a forested area in Catalonia (northeastern Spain) where a long-term drought experiment has been running for decades. Before heading out, we transported sampling equipment from the Max Planck Institute for Biogeochemistry (MPI-BGC) in Germany. In the field, we collected air samples from soil and ecosystem respiration, along with solid samples of leaves, litter, wood, and soils from different depths. Samples were taken from both drought-treated and control plots.
Achievements: About 250 samples were collected, representing all main parts of a Mediterranean forest under both dry and natural conditions.
3. Laboratory work: I spent two months at MPI-BGC processing the collected material for radiocarbon analysis and performing soil incubations to obtain root-free soil respiration samples. The processing involved drying, sieving, grinding, and weighing samples to determine their carbon content, as well as extracting carbon from gases collected in the field and from soil incubations.
Achievements: Approximately 250 samples were successfully prepared and analyzed at the MPI-BGC 14C laboratory, providing detailed radiocarbon signatures for each forest component.
4. Data analysis: Data analysis took place in several stages to address different research goals. For the Mediterranean forest, we analyzed 25 years of drought experiment data to identify long-term patterns and trends. The radiocarbon results were then examined using statistical methods and discussed with experts, including a collaborative visit to Lawrence Livermore National Laboratory (LLNL) in Livermore, CA, to work with K. McFarlane, a specialist in ecological radiocarbon applications.
At a global scale, we analyzed data from multiple models—ranging from CMIP6 and TRENDY climate simulations to atmospheric inversion products including CAMS and CarboScope, and X-BASE—to assess how carbon sequestration has varied across the planet over time.
Achievements: We characterized how carbon moves and is stored in different parts of a Mediterranean forest and quantified how much carbon ecosystems worldwide have captured historically, revealing differences among models and regions.
5. Modelling: Using field and laboratory data, we developed a new model that simulates how carbon flows through a Mediterranean forest and how long it stays in each part of the ecosystem. At the same time, we created a method to combine results from multiple Earth System Models (ESMs) into a single, more reliable ensemble estimate.
Achievements: A model that represents carbon transit time and cycling in Mediterranean forests, plus a new technique for ensembling data from global climate models.
6. Advancing future opportunities: Beyond research, I also worked to secure future career and funding opportunities. I applied to postdoctoral programs such as Beatriu de Pinós and La Caixa Junior Leader (2024 edition and the latest round, which is still pending). I also successfully earned a competitive two-year research position at CREAF to prepare a European Research Council (ERC) proposal.
Achievements: Strengthened experience in scientific proposal writing, secured continued funding, and laid the groundwork for building my own independent research group.
The main innovation of this project lies in connecting the theoretical concepts of carbon transit time and carbon sequestration with global carbon models and data from a unique long-term drought experiment in a region highly affected by water scarcity. This integration will enable the calculation of the Carbon Benefit of Sequestration—that is, the amount of global warming avoided thanks to the carbon stored by ecosystems. The project will thus provide a clear and practical tool to support discussions on climate change mitigation policies and inform forest management both locally (in Mediterranean regions such as Catalonia) and globally.
While various local studies have explored how soil decomposition relates to soil moisture and temperature, this is the first initiative to directly assess the effect of drought on the time carbon remains in the soil-vegetation system—and on its climate benefit. In doing so, this multidisciplinary research will increase holistic understanding of ecosystem carbon dynamics, allowing for improved estimates of how long sequestered carbon remains out of the atmosphere and how this duration varies with soil moisture.
At the same time, the project investigated potential positive feedbacks between drought and global warming resulting from changes in ecosystem carbon permanence, providing policy-relevant insights and actionable outputs to aid in the design of climate mitigation strategies.
Furthermore, this project was the first to address the connection between Earth System Models, Dynamic Global Vegetation Model outputs, and global data-driven models and metrics that jointly account for both the amount of carbon sequestered by ecosystems and the duration of its storage. It involved the calculation of global carbon debt maps under different scenarios, using the pre-industrial era as a baseline.
While various local studies have explored how soil decomposition relates to soil moisture and temperature, this is the first initiative to directly assess the effect of drought on the time carbon remains in the soil-vegetation system—and on its climate benefit. In doing so, this multidisciplinary research will increase holistic understanding of ecosystem carbon dynamics, allowing for improved estimates of how long sequestered carbon remains out of the atmosphere and how this duration varies with soil moisture.
At the same time, the project investigated potential positive feedbacks between drought and global warming resulting from changes in ecosystem carbon permanence, providing policy-relevant insights and actionable outputs to aid in the design of climate mitigation strategies.
Furthermore, this project was the first to address the connection between Earth System Models, Dynamic Global Vegetation Model outputs, and global data-driven models and metrics that jointly account for both the amount of carbon sequestered by ecosystems and the duration of its storage. It involved the calculation of global carbon debt maps under different scenarios, using the pre-industrial era as a baseline.