Water resources, climate change and the nexus
The complex interdependencies between climate change, water and other social and environmental factors present a challenge for researchers and policy makers.
Scientific consensus supports the conclusion that human activity is the primary driver of recent global warming and that there has been “a detectable human influence on the global water cycle”. These climate change impacts on water are complex and affect different regions in different ways.
At the same time water resources have been subject to increasing stress from other factors - manufacturing, agricultural activity and domestic use being the most obvious – and these demands are projected to increase with populations rising and urban expansion accelerating in water-scarce areas.
Governments have identified water as a key to climate change adaptation (it’s mentioned in 93% of national climate action plans) and most efforts to reduce greenhouse gas emissions depend on reliable access to water resources.
It is perhaps surprising then that, until Paris in 2015, water management as a topic had been conspicuously absent from the climate change negotiations and the Paris Agreement still failed to mention water in any substantive way.
In Marrakech in 2016, water finally took centre stage in the conference proceedings with a dedicated “Action Day for Water” and the launch, by the Moroccan Government, of the Water and Climate Blue Book.
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Science and complexity
A starting point in trying to address water issues in the context of climate change is to try to identify and understand the interdependencies between climate change, the water cycle and other demographic, economic, environmental, social and technological forces.
The science documenting the impact of climate change on water resources is strong. The 2014 IPCC Fifth Assessment Report says there is robust evidence that climate change will reduce renewable surface water and groundwater resources in most dry subtropical regions and that this will most likely intensify competition for water between sectors. The report particularly highlights increased risks in urban areas, including from extreme rainfall, inland and coastal flooding, drought and water scarcity. These risks are amplified for those lacking essential infrastructure and services or living in exposed areas. Rural areas are also expected to experience major impacts on water availability and supply with this in turn causing shifts in the production areas of food around the world.
But, when it comes down to understanding what impact efforts to mitigate and adapt to climate change will have the IPCC found that the complexity of these relationships between water, environmental and human factors means that the “tools to understand and manage these interactions remain limited.”
The Water Energy Food Nexus
In attempting to deal with this complexity and develop policy recommendations to tackle climate impacts on water resources, many key institutions have applied a conceptual framing of these inter-relationships known as the Water Energy Food (WEF) Nexus. The Nexus approach tries to build an understanding of the synergies and trade-offs between competing demands for water, land and energy-related resources by moving away from a sectoral framing of resource management towards a more integrated perspective.
Since it emerged the Nexus approach has been widely adopted and adapted to analyse the potential impacts of different policy measures and approaches that could be used to improve water management across different sectors in response to climate change.
A good example is the World Bank’s development of the “Water-Climate Nexus” which uses economic modelling to “document the drivers of the changing patterns in supply and demand for water in a climate change impacted world, and to offer solutions which ensure that water does not become a constraint on prosperity”. Their “High and Dry” report, despite warning that “water scarcity, exacerbated by climate change, could hinder economic growth, spur migration, and spark conflict”, ends up reaching the reasonably upbeat conclusion that, for most countries, taking action to allocate and use water resources better can negate the negative impacts of climate change. Among the instruments they put forwards as being most effective include better planning for water resource allocation, adoption of incentives to increase water efficiency, and investments in infrastructure to secure water supplies.
Not everyone is happy with the Nexus approach as it stands however. Methodological criticisms argue that the nexus approach adds little to other resource management tools, like Integrated Water Resource Management for example, and has failed to integrate emerging concepts of sustainable development.
Perhaps more seriously, it’s economic focus on balancing trade-offs between actors, the fact that it promotes a narrative of scarcity and looming crisis, some argue, leads towards a over-emphasis on solutions that involve investments in large-scale infrastructure.
At the same time the number of large influential global policy actors promoting it has all raised concerns in some quarters that the resulting power inequalities often restrict the emergence of alternative framings and “close down the consideration of alternative development pathways”.
Certainly, for now at least, the Nexus is fairly ubiquitous but most critics seem focused on evolving and improving the analytical framework and tools that the Nexus approach provides, rather than trying to replace it with something else entirely.