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).
