Imagine another Earth, just like ours, but running a year ahead. Observing it, we could foretell events over the coming weeks or months, and take action to avoid catastrophes.
There is no such planet. Even if there were, conditions there would diverge rapidly from ours, so it would provide no guidance on our future. But we can build a model of Earth in a computer and use it to study likely futures and the efficacy of planned interventions. The components of this model are called digital twins.
The Earth system is so complex that a simulation model of the entire system is beyond our current capacity. However, software based on physical and mathematical laws can simulate specific aspects of the system. Earth system models include components for the atmosphere, the hydrosphere, the lithosphere, the biosphere and more. They can predict weather and climate, but also provide guidance on complex environmental challenges in agriculture, biodiversity, public health, migration, energy, transport and water supply.
Earth system models produce realistic flow patterns which, when visualised with computer graphics, are indistinguishable from movie loops constructed using satellite images. But, to plan responses and avoid unintended consequences, we need a finer-grain view. Digital twins are software replicas, virtual environments of interacting components that model the ocean, the atmosphere or the biosphere.
Destination Earth
A workshop on digital twins and Earth system modelling was held in the Convention Centre Dublin recently, organised by the Destination Earth national group. Destination Earth (DE) is a flagship initiative of the European Commission to develop highly accurate digital models of the Earth. The aim is to model and monitor natural phenomena and anticipate hazards. The running of digital twin systems requires the most powerful computing machinery available. The ambitious plans of DE for allocating high-performance computer resources were described.
Before major policies are decided and implemented, their effects can be studied in the computer; a wide range of alternative strategies can be compared, to optimise choices
Three major European scientific agencies, the European Space Agency, the meteorological satellite agency, and the European Centre for Medium-range Weather Forecasts (ECMWF) are key players in DE. ECMWF is implementing the digital twin engine, the complex software and data services needed for Earth system digital replicas, as well as the first two digital twins, on climate change adaptation and on weather-induced extremes. Studies of severe flooding in Europe were described at the workshop. The digital twin for extreme weather impacts will predict floods, both fluvial and tidal, and their impacts.
DE will help us to plan adaptation strategies and mitigation measures. It will enable the development and testing of scenarios for more sustainable development. These are known as “what if” scenarios. Before major policies are decided and implemented, their effects can be studied in the computer; a wide range of alternative strategies can be compared, to optimise choices.
How resilient is Ireland to the changes that inevitably will come? This question is occupying our DE national group, chaired by Met Éireann, which involves 30 departments and State agencies. Political decisions must be based on solid scientific evidence. DE aims to provide the best possible tools to help in building a sustainable future. The conference showed how Ireland can contribute to this. The DE website is at https://destination-earth.eu/.
Peter Lynch is emeritus professor at the school of mathematics and statistics, University College Dublin. He blogs at thatsmaths.com