A book launched last week by the World Bank Group (WBG) entitled ‘Confronting Climate Uncertainty in Water Resources Planning and Project Design’ addresses an important gap in current methods used to assess and manage the risks that global climate change poses for water resources projects. The WBG published this book in response to a lack of a general methodology for assessing the significance of climate change risks relative to other risks for water resources projects that they fund and implement. The ‘bottom-up’ approach used by the WBG facilitates stakeholder involvement in decision-making process from the beginning. It examines system vulnerabilities, enables stakeholder input into design changes to reduce them and strikes a delicate balance between climate change related and non-climate change related risks for water resources projects.
we have a right to question whether those responsible for water resources and associated infrastructure projects are adequately taking uncertainties into account
According to the WBG, the uncertainties associated with global climate change (particularly those related to future water quantity and quality) are such that we have a right to question whether those responsible for water infrastructure projects are adequately taking those uncertainties into account. The robust bottom-up approach used in this book is in contrast to the traditional top-down approach to assessing climate change risks. A top-down approach encompasses the use of general circulation models (GCMs) to describe likely future climate scenarios, modelling the impacts of those scenarios and finally determining climate adaptation options. GCMs are computer based models that explain how physical conditions in the atmosphere, ocean or on land vary across the globe.
The importance of taking a different approach to climate change risk assessment is underscored by the WBGs assertion that relying on GCMs is limited by two fundamental problems:
- Firstly, the degree of uncertainty associated with future climate change can not be reduced within the temporal and spatial scales of water resources projects – thus presenting a risk assessment problem. Of all models available to a project planner, GCMs are the least able to generate local hydrological extremes such as floods and drought – the most important variables for water resources projects.
- Secondly, if climate change related risks are quantified as part of a risk assessment, it is unclear in the majority of cases whether the effects of climate change on a water resources project are more or less significant than non-climate change related factors such as demographics, land use and economic changes.
The WBGs approach employs a unique decision tree model they specifically developed to provide guidance for the application of climate change risk assessment techniques and advanced risk management tools. The structure of the tree is based on decision scaling which is a bottom-up, robust and scientifically defendable approach that uses a stress test to identify vulnerabilities; and simple, direct techniques that reduce vulnerabilities in a systematic manner through targeted design modifications. This decision tree framework was designed with the efficient use of human and financial resources in mind.
The WBGs decision tree model of assessment consists of the following four phases:
1. Project climate sensitivity screening – to determine if a project does require climate change o be taken into account
2. Initial analysis – a project scoping exercise conducted using a simplified water resources system model that compares climate impacts with other impacts including existing variability and population growth
3. Climate stress testing – an extensive climate risk analysis combining historical data, global climate model projections, a hydrologic-economic water system model and other variables
4. Climate risk management – to determine if a project can cope with potential climate change risks. If not, the project must be revised and either subjected to another stress test (Phase 3) or redesigned completely and subjected to climate sensitivity screening (Phase 1).
With approximately 700 million people around the world currently unable to access clean water it is critical that Government planners globally take note of the World Bank Group publication and their bottom-up approach. Their scientifically defendable method successfully blends climate change risk assessment and risk management tools, marking a significant improvement to the currently available approaches to fighting global climate change.
While those responsible for water resources projects within Governments may not have an intricate scientific knowledge of climate change, the ‘Confronting Climate Uncertainty in Water Resources Planning and Project Design’ book can provide a credible and straightforward resource that helps guide them to appropriately plan, design and implement water resources projects.
The WBG publication makes a significant contribution to climate change risk assessment and management for water resources projects
As a scientist I can fully appreciate the need for defendability – it is fundamental to the process of science. I can also appreciate the need for tools to be straightforward. The WBG publication makes a significant contribution to climate change risk assessment and management for water resources projects as a result of its bottom-up approach which strikes an important balance between climate and non-climate related risks for water resources projects. I believe that this approach is sufficiently flexible and robust to ultimately be used for all projects being planned, designed and implemented by Governments around the world.