Studying lack of coordination in climate change mitigation

River basins and reservoirs supply drinking water, help irrigate crops and generate energy. This water-energy-food nexus is a major focus of scientific research as the world seeks to address climate change and sustainability. To help guide future policy decisions, an international team led by the Environmental Intelligence for Global Change Lab at Politecnico di Milano in collaboration with researchers from Tufts University, Pacific Northwest National Laboratory, and Cornell University created an integrated hydrologic, irrigation, and power systems model to simulate thousands of possible scenarios of global change, climate mitigation policies and their effects. A key finding from their results: it will be necessary to carefully coordinate global policies to reduce unintended harmful local impacts to African river basins.

The study, published in Nature Climate Change, explored more than 7,000 future scenarios that combined different climate and socio-economic projections with alternative mitigation policies. Results showed that policy fragmentation between developed and developing countries in their approach to addressing carbon emissions from land-use can increase vulnerabilities in African basins. Specifically, the research shows how such fragmented policies could encourage proliferation of agricultural projects in Africa.

While on its face, that would seem a positive development, a rapid increase in agricultural land use could generate irrigation demands two times higher than under globally coordinated approaches to emissions reduction. Higher irrigation demands also constrain the availability of water resources for hydropower production, particularly in river deltas, which could add stress to African nation economies and ecosystems.

Coordinated global policies can address climate change while at the same time reducing local vulnerabilities to strains on the water resources needed for energy, drinking water, food production, and other industrial applications.

The study sheds light on the importance of connecting global climate change mitigation policies to their potential impacts on local social and economic activity.

“Water resources management studies are mostly developed within the physical boundaries of river basins and seldom capture interconnections across larger scales. This research develops one of the first “global to local” studies, where the impacts of global mitigation policies are downscaled and analysed at the finer river basin scale” says Professor Andrea Castelletti, head of the Environmental Intelligence Lab at Politecnico di Milano. “Our results show how globally designed strategies should be reconsidered in light of unexpected and unintended local impact to foster a more sustainable transition to a future of low carbon emissions.”

The research is one of the main outputs of the EU Horizon 2020 project Decision Analytic Framework to explore the water-energy-food Nexus in complex transboundary water resource systems of fast developing countries (DAFNE). The DAFNE project incorporates tools from different research fields -- mathematical models, optimization algorithms, climate science and socio-economic projections -- to consider the system-wide impact of alternative development pathways. In other words, it looks at the global impact of development policy, while enabling one to zoom in on local effects.

In this study, DAFNE was used to promote participatory planning and management of water resources to identify sustainable development pathways in the Zambezi Watercourse and the Omo-Turkana Basin.

“There is no doubt that it is absolutely critical to immediately act to mitigate the climate crisis, but our approach can’t be focused on sectors in isolation or ignore how local challenges may evolve.” says Dr. Patrick Reed, Joseph C. Ford Professor of Engineering at Cornell University. “The Zambezi serves as an important example in this study that illustrates how global land use policies can increase tensions and trade-offs across water, energy, and agricultural systems.”

“Every day we’re learning just how interconnected the world is, that actions taken in one region or sector can have far reaching impacts,” says Dr. Jonathan Lamontagne, Assistant Professor in Civil and Environmental Engineering at Tufts University. “Our study is an early example tying local effects to global policies in the context of reservoir management.”

“We can’t emphasize enough the importance of a coordinated approach to climate change policy,” says Dr. Matteo Giuliani, Assistant Professor in the Environmental Intelligence Lab at Politecnico di Milano, who led the study. “Unintended, harmful local effects of policy can create resistance to constructive action. Policy foresight provided by the computer model can help avoid that scenario.”