From global models to local decisions

From global models to local decisions

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Date: 15th May 2014
Author: CDKN Africa
Type: Feature
Organisation: START
Tags: climate data, CORDEX-Africa, regional climate models


Jon Padgam, Deputy Director of START, reflects on the challenges and opportunities for linking climate information on Africa with user needs

The changing nature of climate variability and increasing extremes pose a notable threat to sustainable development where there is a high risk of exposure to climate stress.  Understanding vulnerability and potential impacts, and responding through adaptation decisions and policy, requires climate information that is defensible, scale relevant and tailored to user needs. Unfortunately, the present state of regional climate change prediction presents the user with a confusing array of data sources that are contradictory and delivered with minimal understanding of what is robust and defensible data, or on how to interpret and apply it to decision making.  This state of affairs undermines the value of development actions seeking to reduce risk, while increasing the risk of maladaptation.

The growth of new multi-model and multi-method data sets, most notably through the World Climate Research Program’s CORDEX initiative, offers a new opportunity to address the challenge of regional scale information. The central aim of CORDEX-Africa, which is led by the University of Cape Town’s Climate Systems Analysis Group in partnership with START, is to promote data analysis from a regionally based user’s needs perspective by regional climate scientists in collaboration with users of climate data. This approach provides direction to the modeling community as to which climate parameters are useful for decision making in different contexts, and therefore have potential for uptake. It also affords a transformative opportunity for capacity building in developing nations, by training the early career scientists to partner with end-users of climate information for co-exploration of the data to the mutual benefit of both communities.

The climate data co-exploration approach was tested through a workshop held in Dar es Salaam in February 2013 that sought to develop a guidance framework for using climate model data to support adaptation planning in Africa. The main purpose of this workshop was to pilot the methodology together with interdisciplinary teams from Addis Ababa, Kampala, Dar es Salaam, Maputo and Lusaka. The participants for this event were technical experts in the areas of meteorology and climatology, agriculture, water resource management, disaster risk management and land-use planning, within government, university and non-government spheres. The climate-application focus of the workshop was on peri-urban areas of these five cities, which typify the intensive land-use change pressures from urban encroachment that African cities are facing. These pressures have implications for, among others, food production, water resources and flood risk management for cities.

The learning process for integrating climate data into decision making took place through the development of a vulnerability matrix that encompassed non-climatic and climatic stressors acting on important ‘exposure units’ in peri-urban areas, such as crop and livestock production, inland fisheries, informal trading, transport corridors and other critical infrastructure, and water supplies.

The matrix development occurred through a step-wise process that involved identifying critical exposure units related to livelihoods, infrastructure and services that occur in peri-urban areas, identifying non-climate stressors that act on these exposure units and then identifying where climate stressors place additional risks to the exposure units. This step-wise process allowed the city teams to identifying critical vulnerabilities in livelihoods, infrastructure and services of their peri-urban environments that then provided a targeted, contextual basis for identifying climate sensitivities to which they could integrate climate data and information.

Over the three days of the workshop, the city teams, comprised of people with mixed expertise and perspectives, worked closely together to animate the layers of the matrix and discover both the potential and the limitations of what the climate data provided for decision making. In the end the city teams constructed a brief narrative about what information the climate data provided them to better understand critical vulnerabilities. Did the climate data indicate anything about interacting climate and non-climate stresses? Where were there limits to what the climate data was able to provide?

For many of the participants, this was their first in-depth exposure to climate model data even though they make daily decisions in their professional lives where an understanding of climate is important. This experience brought to light many common discoveries that the teams made in going through the climate data analysis.  For example, the teams came to understand the substantial limits of global circulation model (GCM) data in terms of the broad spatial and temporal scales of the GCMs, which are out of synch with decisions made at city levels. The teams also gained insights as to the convergence and divergence in climate data between GCMs and regional climate models (RCMs), and the usefulness of RCMs in that they provide a broader set of climate parameters relevant to decision making than do GCMs. The teams also came to appreciate the substantial caveats to consider in using RCMs.

The co-exploration approach developed through this workshop is a start in helping to build a more informed and skeptical base of users of climate data in Africa and to encourage direct engagement between these user groups and the suppliers of climate data. The recent proliferation of climate data portals and tools that purport to provide a downscaled climate data “answer”— in the form of a single method, or single model, or even a single mean value of a given parameter— fail to inform the user as to the skill of any inherent information, or about the degree of model data uncertainty that would allow an educated user to evaluate the validity and robustness of the data.

The group from Addis Ababa emphasized the need for continued collaboration: “There needs to be knowledge transfer after this workshop to Addis Ababa’s Climate Change Forum. We need to talk about how many people are illiterate in climate information. We have learned a lot and gained knowledge on elements and sectors affected by climate change. But we need to continue these things with other people and other projects to enhance their abilities.”

We occasionally invite bloggers from around the world to provide their experiences and views. The views expressed here are those of the author, and not necessarily those of CDKN.

For more information on the CDKN-supported project, visit the project page.

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