Unravelling the mechanisms behind Multi-Year Droughts

Project Information

MultiDry

Grant agreement ID: 101075354

DOI

10.3030/101075354

EC signature date 2 December 2022

Start date 1 September 2023

End date 31 August 2028

Funded under

• European Research Council (ERC)

Total cost

€ 1 500 000,00

EU contribution

€ 1 500 000,00

Coordinated by

UNIVERSITEIT UTRECHT
Netherlands

Periodic Reporting for period 1 - MultiDry (Unravelling the mechanisms behind Multi-Year Droughts)

Reporting period: 2023-09-01 to 2026-02-28

Summary of the context and overall objectives of the project

Recent decades have seen a doubling in multi-year droughts around the world, resulting in long-lasting impacts on streamflow, groundwater and vegetation. These, in turn, negatively affect agriculture, drinking water supply, hydropower, shipping, and ecosystems. Multi-year droughts are projected to become more frequent and longer due to climate change, potentially reducing the recovery time between them. There is a need to understand the magnitude and frequency of multi-year droughts both in present and how these will change in the future.

MultiDry will focus on radically advancing our understanding of the drivers and mechanisms of multi-year droughts through the creation of new models, novel scientific datasets, and the development of a basis for reliable projections of future multi-year droughts. The MultiDry results will inform policymakers and water managers around the world on future water challenges. Additionally, MultiDry will produce new knowledge needed to quantify future drought vulnerability around the world and improve global hydrological modelling of these events and drought preparedness.

Work performed from the beginning of the project to the end of the period covered by the report and main results achieved so far

As multi-years droughts become more prominent and last longer, MultiDry can contribute to the understanding of drivers, impacts, and feedbacks that are fuelling this rise in multi-year droughts. Therefore, the main aim of this proposal is:

To unravel the complexity behind multi-year droughts, and identify the drivers and interactions with vegetation, groundwater systems and human water use.

There is a need to understand the environmental and societal impacts of a multi-year droughts in a holistic manner. To achieve this, observations and modelling will be combined to examine multiple factors that impact the propagation of multi-years droughts throughout the bio-hydrological cycle including:

Challenge 1: identify the atmospheric, oceanic and land drivers.
Challenge 2: determine the impact on vegetation and groundwater.
Challenge 3: linking water demand and groundwater dynamics.
Challenge 4: identify the dominant components that determine drought characteristics.
Furthermore, the roles of soil moisture, vegetation and water resource management need to be understood, along with how these interact with each other and the atmosphere. The coupling of atmosphere, vegetation, and hydrology will contribute to understanding multi-year drought occurrence, duration, and recovery.

Progress beyond the state of the art and expected potential impact (including the socio-economic impact and the wider societal implications of the project so far)

Taking the information provided by Challenges 1 to 3, a new framework can be created that couples the atmosphere, vegetation, and hydrology to study their relative contributions to the occurrence, duration, and recovery of multi-year droughts. This framework will be the first holistic system based on both observations and modelling for multi-year drought assessment. Additionally, the interactions between the different components will be quantified, and the required drought recovery times to mitigate drought legacy effects will be identified.

Subsequently, the impacts of the different factors will be coupled to local properties including climate, vegetation, soil physical, groundwater, and socio-economic characteristics, to identify relationships between drought vulnerability and local characteristics. Overall, the final product will, for the first time, quantify the impact of climate change and its variability on multi-year droughts. This, in turn, provides a foundational framework for future climate assessments and can aid in scenario development for integrated assessment models.