AMMA-2050 NEC05274

Lead Research Organisation: University of Leeds
Department Name: School of Earth and Environment


The climate of West Africa is subject to some of the most variable rainfall patterns observed anywhere in the world. In the past, the region has suffered several decades of severe droughts, whilst more recently major flood events have struck a number of the region's rapidly expanding cities. The consequences of these climatic extremes for the population have been particularly pronounced due to widespread and severe poverty. Global climate change, coming on top of such a variable and unpredictable regional climate, poses a major threat to the populations and economies of West Africa. Although the pathway from climate change to human suffering in West Africa is very short, there are some key bottlenecks to using climate projections to mitigate against risks to the population. Critical gaps exist in knowledge of how West African climate will change over the course of the 21st century, and the uncertainties make it almost impossible for agencies to deliver well-informed plans for the coming decades in critical areas such as food security, urban development and water. Even with the best climate information, it remains a significant challenge to integrate the scientific knowledge into planning and management structures. This collaborative project between scientists and policy makers in West Africa and Europe will, on the one hand, increase understanding of the regional climate and how it will change, and on the other, apply that knowledge to practical development questions.

One of the key challenges for climate science is to understand how the changing composition of the atmosphere (notably CO2) will impact on the frequency and intensity of extreme events such as floods and droughts. In West Africa, these events are tied to the behaviour of convective rain storms; when storms are particularly intense or occur in rapid succession, devastating floods may result, whilst a week or two without storms during the wet season can trigger crop failure. Climate scientists rely on computer simulations of the global atmosphere, oceans and continents, yet these models have a very crude description of convective storms. For the first time, a new generation of regional climate models is emerging which realistically depict storms, and critically, how storms respond to factors such as land and ocean conditions, and increases in CO2. AMMA-2050 will use these new computer simulations alongside conventional climate models and historical observations, to understand why the statistics of key climate extremes are changing, and what this tells us about climate and its extremes in future decades.

The outputs from the models will be used to examine impacts on key sectors in West African society, notably water and agriculture. Adaptation options will be explored, for example through the use of alternative crops, taking account of the inherent uncertainties in climate information, and the ways in which it is interpreted by decision-makers. We will focus on two questions. Firstly, in Senegal we will identify sustainable agricultural adaptation strategies and the policy frameworks to support those options. Secondly, we will examine how climate changes are likely to affect flooding in the rapidly growing city of Ouagadougou in Burkina Faso. The research and capacity building work of AMMA-2050 will help develop a new generation of African researchers and decision-makers, well-placed to respond to the requirements of West African nations. Within AMMA-2050, end-users have an important role, and their needs are embedded in project design and delivery, such that outputs will be responsive to their needs, and delivered in a format that is easily used. Enhanced resilience is an important aim of the project: it starts with improving our understanding of the climate signal over West Africa and leads through to decisions being made in specific pilot studies that showcase the importance of using improved and impact-sensitive science outputs.

Planned Impact

The primary impacts of AMMA-2050 will be: the enhanced uptake of the products of climate science in medium term decision-making in West Africa; and the growth of regional expertise in climate science, its impacts and the science-decision making interface.

The AMMA-2050 project combines novel scientific excellence along with fully integrated participation of stakeholders. We are building on the community of researchers and operational partners established in AMMA since 2003, which already has a strong track record of collaborative, multidisciplinary and impact-focused science. Within AMMA-2050 we aim to use this community to derive practical impact from our research, and to demonstrate specific applications of robust climate projections to planning in the agricultural and urban flood-risk sectors.

In order to deliver impact in the use of reliable climate information in these sectors, it is necessary to address the fundamental weaknesses in current climate science and the information it delivers. This physical science research in Pillar 1 of the project will be conducted in very close cooperation with a programme of applied research (Pillar 2) and practical demonstration projects (Pillar 3). Sustained communication among these groups is essential to the delivery of practical outputs that are relevant to users. For example, key measures of high-impact climatic quantities (drought, flooding etc) will be defined within the whole consortium and coordinated at the top level, so that such measures are both useful to users within the demonstration projects, and scientifically rigorous in the climate models. Furthermore, the credibility of climate information relies on the transparent evaluation of the information in terms of its accuracy and reliability. The legitimacy of the climate information will be ensured by the co-production of knowledge by institutions in Africa and Europe and by stakeholders and scientists working together on the project. Since excellent science is a major driver of the work of AMMA-2050, we aim to publish our results in the top peer-reviewed journals, and present the research at national and international meetings.

Existing partnerships and networks are the foundation upon which our communications are built. Within AMMA-2050, stakeholders have a defined role in ensuring the work is demand-led. Our knowledge exchange activities will draw on the networks our partners have in West Africa as well as involving boundary organisations such as the CCKE-Unit. Ongoing engagement of these organisations will ensure outputs of AMMA-2050 are communicated beyond our original list of stakeholders to a wider audience of interest groups. In this, we will work with regional and international agencies such as the Volta Basin Authority (VBA), the Climate Change, Agriculture and Food Security (CCAFS) programme, the African Centre of Meteorological Application for Development (ACMAD), the Economic Community Of West African States (ECOWAS), and government departments such as the Direction de la Gestion et de la Planification des Ressources en Eau (DGPRE) in Dakar.

The capacity building activities of AMMA-2050 will involve a balance of staff time visiting African and European research centres and policy placements totalling more than 60 months. Alongside attendance at international conferences and annual consortium meetings, plus significant leadership roles, the project will help to develop a skilled workforce and a new generation of leaders in African research. The ultimate beneficiaries of AMMA-2050 will be the populations of West Africa, who will benefit from more effective use of climate information in planning for an uncertain future. This is particularly so in the key areas of food security, via informed adaptive cropping and agricultural policies, and cities which are resilient to future flood risk.


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Description We have developed a method for determining the onset of the annual rains in West Africa, on a regional rather than local scale.

The rains are very variable, both in terms of space and time. Some places a few kilometres apart may experience big differences in the timing of the first sustained rains of the wet season. For this reason, it has been difficult to evaluate weather and climate predictions of the onset of the rains, and to communicate any changes to stakeholders such as farmers.

We have devised an analysis of "Local Onset Regions" which aggregate local onsets up to the largest possible regional scale. These are potentially useful because (a) they define areas where the onset of rain is coherent (and areas where it is not), and (b) they can be related to large-scale climatic drivers of the onset.

We have shown that extreme storms in West Africa have increased threefold since the 1980s. The cause of the change seems to be changes in the windshear, leading to stronger storms able to extract more water from the atmosphere, rather than a moistening of the atmosphere.

We have analysed the ability of climate models to capture the response of the rainfall to these drivers. We find that the models struggle to show a sufficiently strong response to the windhear.
Exploitation Route Weather forecasters and agricultural planners in Africa should be able to use the Local Onset Region (LOR) method to understand the skills and limitations of the forecasts they are using. For instance, they may expect forecasts to be consistent within known LORs, but not beyond these scales. They may also have local information regarding climatic "drivers" of particular LORs (we see that in some LORs, for instance, it is the change in wind direction some 6 weeks earlier that precedes rainfall onset).

Other researchers are using the LOR methods to analyse monsoon onsets in Africa and SE Asia, and their relationships to climatic drivers.

Our results showing intensification of storms in recent years, and projection to the future, are being used to influence planning for response to extreme events in West Africa.
Sectors Agriculture, Food and Drink,Energy,Environment

Description The knowledge developed on intensification of extreme rains, in the past decades and in future projection, is being used in planning for future flooding in Ouagadougou as part of the AMMA-2050 Pillar 3 work.
First Year Of Impact 2019
Sector Environment
Impact Types Policy & public services

Description CEH-Leeds 
Organisation UK Centre for Ecology & Hydrology
Country United Kingdom 
Sector Public 
PI Contribution My team in Leeds conduct atmospheric studies using observations, models and theoretical ideas. I have also led a number of projects and field experiements in which we have collaborated with CEH.
Collaborator Contribution Expertise in land-surface processes. Expertise in land-atmosphere interactions. Expertise in land-atmosphere climate dynamics. Data analysis, especially remote sensing of rainfall and land surface state. Leadership of projects. Co-supervision of PhD students.
Impact This is a multidisciplinary partnership in the area of land-atmosphere interaction. It has resulted in a large number of high-impact papers, successful jointly-supervised PhD studentships, and successful impacts, especially in Africa.
Description Met Office 
Organisation Meteorological Office UK
Country United Kingdom 
Sector Academic/University 
PI Contribution Our research group analyses atmospheric processes in order to better represent them in the Met Office's forecast models. We also use those forecast models in our research, and evaluate their performance in order to identify the best strategies to improve the models.
Collaborator Contribution The Met Office brings its models and its datasets to the partnership, in addition to the considerable expertise of its staff. The Met Office also represent a conduit to the impact of our research for society, through its provision of operational weather and climate forecasts.
Impact Our research has influenced the Met Office strategy for model development, especially in regard to high-resolution models, and the convective parametrisation scheme. We have jointly influenced international strategy for atmospheric research and measurements.