Attributing impacts of external climate drivers on extreme weather in Africa
Lead Research Organisation:
University of Oxford
Department Name: Geography - SoGE
Abstract
Given limited progress in reducing greenhouse gas emissions and uncertain potential for adaptation to many impacts, attention in vulnerable regions and sectors is turning to the question of "loss and damage". Who should bear the costs of human influence on climate that cannot be neutralized by adaptation? This debate is impeded by lack of robust estimates of what these costs are. Despite concerted efforts to compile inventories of emissions, we still have no agreed method of establishing how countries, companies or individuals are being adversely affected by anthropogenic climate change in the context of other drivers of regional environmental change.
Many of the most important impacts of climate change are related in some way to high-impact weather events (HIWEs), such as floods, storms, and droughts. Compiling an impact inventory requires documenting the impacts of individual events and how these events are affected by multiple climate drivers and internal climate variability. We will build on research into HIWEs and their impacts under THORPEX-Africa.
Studies assessing the link between climate change and extreme weather have so far focused primarily on mid-latitude phenomena and the impact of rising greenhouse gases. Yet in many tropical regions, short-lived climate forcings (SLCFs) such as sulphate, mineral and black carbon aerosols and tropospheric ozone may have played a larger role in changing patterns of weather risk to date. Substantial reductions in anthropogenic SLCFs could be achieved in only 20 years. Including measures already planned to reduce emissions of sulphate aerosol precursors, SLCFs may dominate near-term changes in weather risk. Climate impact assessments used for adaptation planning typically focus on net multi-decadal anthropogenic change, dominated by greenhouse-induced warming. Few address uncertainty in SLCF forcing and response. Hence relying on these and extrapolation of recent trends risks "adapting to yesterday's problem" as key drivers of regional weather are reversed.
Assessing the influence of external drivers on extreme weather is challenging because the most important events are typically rare. The only solution is to rely on simulation models, whose reliability can be tested and if necessary re-calibrated using well-established procedures developed for seasonal forecasting. We will also use the land-surface model JULES for indirect validation in regions with sparse meteorological data. Large ensembles of climate model simulations at relatively high resolution are required for robust statistics of extreme weather events, allowing for uncertainty in both external drivers and simulation models.
This project makes use of the climateprediction.net weatherathome worldwide volunteer computing project. We will quantify the role of various external climate drivers on changing risks of extreme weather in Africa by implementing a regional climate model over the CORDEX-Africa domain and simulate observed weather statistics over recent decades using multi-thousand-member ensembles, systematically excluding the influence of different climate drivers to quantify their effects.
Attribution studies of HIWEs to date have typically focussed on hydrometeorological events themselves, rather than modelling all the way through to their impacts. This can lead to "over-attribution": if a record-breaking weather event occurs that has been made more likely by some external driver, people tend to blame most of the impact of that event on that driver. But much of this impact might also have been caused by a lesser, non-record-breaking, event. Hence accurate assessment requires explicit modelling of changing impact risk, not simply weather risk, so a major focus of this project will using JULES to investigate various impacts and working with impact modellers across Africa to assess the implications of our weather simulations for changing impact risk in other sectors.
Many of the most important impacts of climate change are related in some way to high-impact weather events (HIWEs), such as floods, storms, and droughts. Compiling an impact inventory requires documenting the impacts of individual events and how these events are affected by multiple climate drivers and internal climate variability. We will build on research into HIWEs and their impacts under THORPEX-Africa.
Studies assessing the link between climate change and extreme weather have so far focused primarily on mid-latitude phenomena and the impact of rising greenhouse gases. Yet in many tropical regions, short-lived climate forcings (SLCFs) such as sulphate, mineral and black carbon aerosols and tropospheric ozone may have played a larger role in changing patterns of weather risk to date. Substantial reductions in anthropogenic SLCFs could be achieved in only 20 years. Including measures already planned to reduce emissions of sulphate aerosol precursors, SLCFs may dominate near-term changes in weather risk. Climate impact assessments used for adaptation planning typically focus on net multi-decadal anthropogenic change, dominated by greenhouse-induced warming. Few address uncertainty in SLCF forcing and response. Hence relying on these and extrapolation of recent trends risks "adapting to yesterday's problem" as key drivers of regional weather are reversed.
Assessing the influence of external drivers on extreme weather is challenging because the most important events are typically rare. The only solution is to rely on simulation models, whose reliability can be tested and if necessary re-calibrated using well-established procedures developed for seasonal forecasting. We will also use the land-surface model JULES for indirect validation in regions with sparse meteorological data. Large ensembles of climate model simulations at relatively high resolution are required for robust statistics of extreme weather events, allowing for uncertainty in both external drivers and simulation models.
This project makes use of the climateprediction.net weatherathome worldwide volunteer computing project. We will quantify the role of various external climate drivers on changing risks of extreme weather in Africa by implementing a regional climate model over the CORDEX-Africa domain and simulate observed weather statistics over recent decades using multi-thousand-member ensembles, systematically excluding the influence of different climate drivers to quantify their effects.
Attribution studies of HIWEs to date have typically focussed on hydrometeorological events themselves, rather than modelling all the way through to their impacts. This can lead to "over-attribution": if a record-breaking weather event occurs that has been made more likely by some external driver, people tend to blame most of the impact of that event on that driver. But much of this impact might also have been caused by a lesser, non-record-breaking, event. Hence accurate assessment requires explicit modelling of changing impact risk, not simply weather risk, so a major focus of this project will using JULES to investigate various impacts and working with impact modellers across Africa to assess the implications of our weather simulations for changing impact risk in other sectors.
Planned Impact
End-to-end attribution of climate change impacts is a pressing issue not only for the for the Intergovernmental Panel on Climate Change but especially for users of climate information in farming, decision makers for infrastructure development and adaptation. The interdisciplinary nature of the problem makes co-generation of knowledge essential: attribution of hydro-meteorological anomalies alone is insufficient to demonstrate impact. Calculation of actual harm requires a deep understanding of local confounding factors and changing vulnerability. We propose to address this through demonstration projects (attribution of floods in Kenya, droughts in East Africa and vegetation changes over parts of the continent) and providing funding for two workshop to initiate a network of collaborations within Africa using the established links within THORPEX Africa, the consortia of Regional Climate Outlook Forums (RCOF) in Eastern and Western Africa, and Oxfam projects in drought and flood prone regions of the African continent. At these workshops we aim to bring together a large group of impact modellers using the data provided by the proposed research in Oxford to start the process of compiling an inventory of climate impacts over Africa.
Valuing anthropogenic modification of weather and climate is the ultimate goal of this research. On the ten-year research horizon, there is a clear need for a global inventory of the impacts of climate change to complement current inventories of climate drivers such as national emissions data. This will provide an essential ingredient for evidence-based mitigation and adaptation policies, but will need a firm grounding in the link between climate and extreme weather, drawing on routine attribution assessments which address all weather events, not simply high-profile disasters. This is an especially pressing requirement in Africa which is expected to be hard hit by impacts of climate change in the very near future, is least resilient to changing risks of extreme weather events, and has an underdeveloped inventory at present as impact assessment depends on understanding of meteorological mechanisms and impacts of hydro-meteorological events on agriculture, infrastructure and livelihoods. This will require a sustained international effort: this project will develop and prove some of the necessary methods and demonstrate their feasibility and value in most vulnerable regions of Africa. The workshops are planned to initiate an inventory of climate change impacts from within the African continent itself.
With this close collaboration with established facilitators of climate information for and from Africa as THORPEX and RCOF and linking this to impact assessment in Oxford and provided by Oxfam, we develop also a bottom-up approach to quantifying the actual costs (and benefits) of climate change over Africa which represents a radical departure from the top-down approach of typical Integrated Assessment Models used to calculate the Social Cost of Carbon, which parameterise the net impact of extreme weather, providing limited scope for disaggregation of costs and benefits. In effect, we are addressing the question "what did human influence on climate actually cost me (my company or country) last year?" as opposed to "what would we expect the cost of anthropogenic climate change to be in a typical year of the current decade?"
Additionally we plan to further develop citizen science capacity through collaborations between members of climateprediction.net and modellers in the project team, supported by information provided on climateeducation.net, to understand how climate modelling works, examine evidence of the impact of human influence on climate and inform the attribution of extreme weather events to anthropogenic climate change.
Valuing anthropogenic modification of weather and climate is the ultimate goal of this research. On the ten-year research horizon, there is a clear need for a global inventory of the impacts of climate change to complement current inventories of climate drivers such as national emissions data. This will provide an essential ingredient for evidence-based mitigation and adaptation policies, but will need a firm grounding in the link between climate and extreme weather, drawing on routine attribution assessments which address all weather events, not simply high-profile disasters. This is an especially pressing requirement in Africa which is expected to be hard hit by impacts of climate change in the very near future, is least resilient to changing risks of extreme weather events, and has an underdeveloped inventory at present as impact assessment depends on understanding of meteorological mechanisms and impacts of hydro-meteorological events on agriculture, infrastructure and livelihoods. This will require a sustained international effort: this project will develop and prove some of the necessary methods and demonstrate their feasibility and value in most vulnerable regions of Africa. The workshops are planned to initiate an inventory of climate change impacts from within the African continent itself.
With this close collaboration with established facilitators of climate information for and from Africa as THORPEX and RCOF and linking this to impact assessment in Oxford and provided by Oxfam, we develop also a bottom-up approach to quantifying the actual costs (and benefits) of climate change over Africa which represents a radical departure from the top-down approach of typical Integrated Assessment Models used to calculate the Social Cost of Carbon, which parameterise the net impact of extreme weather, providing limited scope for disaggregation of costs and benefits. In effect, we are addressing the question "what did human influence on climate actually cost me (my company or country) last year?" as opposed to "what would we expect the cost of anthropogenic climate change to be in a typical year of the current decade?"
Additionally we plan to further develop citizen science capacity through collaborations between members of climateprediction.net and modellers in the project team, supported by information provided on climateeducation.net, to understand how climate modelling works, examine evidence of the impact of human influence on climate and inform the attribution of extreme weather events to anthropogenic climate change.
Publications
Black M
(2016)
The weather@home regional climate modelling project for Australia and New Zealand
in Geoscientific Model Development
Boyd E
(2017)
A typology of loss and damage perspectives
in Nature Climate Change
Haustein K
(2017)
A real-time Global Warming Index.
in Scientific reports
James R
(2017)
Characterizing half-a-degree difference: a review of methods for identifying regional climate responses to global warming targets
in WIREs Climate Change
James R
(2014)
Characterizing loss and damage from climate change
in Nature Climate Change
James, R
(2018)
Loss and Damage from Climate Change
Marthews T
(2019)
The Impact of Human-Induced Climate Change on Regional Drought in the Horn of Africa
in Journal of Geophysical Research: Atmospheres
Marthews, Toby R.
(2019)
The impact of human-induced climate change on regional drought in the Horn of Africa
Michaelowa A
(2018)
Policy instruments for limiting global temperature rise to 1.5°C - can humanity rise to the challenge?
in Climate Policy
Mitchell D
(2018)
Extreme heat-related mortality avoided under Paris Agreement goals.
in Nature climate change
Description | Award just started and in progress. But at this stage we have multi output from a regional simulation over North Africa. The model has been run at 50 km resolution, and is currently being run at 25 km resolution. This is the first time such a high resolution simulation will be used over Africa for event attribution. |
Exploitation Route | Developing methods for attribution of impacts for human influence on climate |
Sectors | Environment Government Democracy and Justice |
URL | http://climateprediction.net |
Description | Allen, M. R, Chapter 1 Framing and Context, SPECIAL REPORT: GLOBAL WARMING OF 1.5 ºC |
Geographic Reach | Multiple continents/international |
Policy Influence Type | Membership of a guideline committee |
Impact | SPECIAL REPORT: GLOBAL WARMING OF 1.5 ºC |
URL | https://www.ipcc.ch/sr15/chapter/chapter-1-pdf/ |
Description | Drivers Of Change In mid-Latitude weather Events (DOCILE) - Standard Grant |
Amount | £580,838 (GBP) |
Funding ID | NE/P002099/1 |
Organisation | Natural Environment Research Council |
Sector | Public |
Country | United Kingdom |
Start | 01/2017 |
End | 12/2019 |
Description | Globally Observed Teleconnections and their role and representation in Hierarchies of Atmospheric Models - Belmont Forum |
Amount | £2,500,000 (GBP) |
Funding ID | NE/P006779/1 |
Organisation | Natural Environment Research Council |
Sector | Public |
Country | United Kingdom |
Start | 05/2016 |
End | 05/2020 |
Description | ICBA (International Centre for Biosaline Research) |
Organisation | Institute of Genetics and Molecular and Cellular Biology (IGBMC) |
Country | France |
Sector | Academic/University |
PI Contribution | We have provided model output, and expertise in climate dynamics and extreme weather events. We will lead one paper on model evaluation over Africa, and how extreme events are represented. |
Collaborator Contribution | They have provided local observations over North Africa. They also bring to the table expertise in hydrological modelling and downscaling techniques. They will lead two papers, looking at extremes and general meteorology over North Africa. |
Impact | Only recently started. The collaboration is multidisciplinary |
Start Year | 2014 |
Description | Africa Climate Conference |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | Yes |
Geographic Reach | International |
Primary Audience | Professional Practitioners |
Results and Impact | The activity we present sparked interaction among stakeholders, and prompted discussions of our research. We have been asked to engage other groups with the same activity. |
Year(s) Of Engagement Activity | 2013 |
Description | Blog Entry: What Is Loss and Damage from Climate Change? First Academic Study Reveals Different Perspectives - James, R, Jones, R, Boyd, E |
Form Of Engagement Activity | A broadcast e.g. TV/radio/film/podcast (other than news/press) |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Public/other audiences |
Results and Impact | Challenging Questions in New Security Beat (see URL) |
Year(s) Of Engagement Activity | 2017 |
URL | https://www.newsecuritybeat.org/2017/09/loss-damage-climate-change-academic-study-reveals-perspectiv... |
Description | CCDAIII (Climate Change and Development in Africa III) |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Policymakers/politicians |
Results and Impact | Promoting our work on loss and damage of climate change. Useful discussions afterwards. Stimulated us to write a paper, led by Dr Rachel James (see attached publications). |
Year(s) Of Engagement Activity | 2013 |
Description | Conference Paper: . Loss and damage - the disputed role of causation - Serdeczny, O., Boyd, E., James, R., Jones, R., Otto, F. E. L., Young, H |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Policymakers/politicians |
Results and Impact | 2017 General Conference, European Consortium for Political Research, Oslo, 6-9 September 2017 |
Year(s) Of Engagement Activity | 2017 |
Description | Expert Briefing: Typologies of Loss and Damage and Associated Actions - Boyd, E, James, R, Jones, R |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Policymakers/politicians |
Results and Impact | Expert Briefing to the Executive Committee of the Warsaw International Mechanism for Loss and Damage associated with Climate Change Impacts, Bonn, 26 April 2016 |
Year(s) Of Engagement Activity | 2016 |
URL | http://unfccc.int/adaptation/groups_committees/loss_and_damage_executive_committee/items/9548.php |
Description | Policy Brief: A spectrum of view on Loss and Damage |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Professional Practitioners |
Results and Impact | Policy briefing across academia and industry published by Oxford University Environmental Change Institute |
Year(s) Of Engagement Activity | 2016 |
URL | http://www.eci.ox.ac.uk/publications/161101.pdf |
Description | Presentation on Perspectives on Loss and Damage - Boyd, E, James, R, Jones R |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Policymakers/politicians |
Results and Impact | Resilience Academy, Bavaria, 6 September 2016 |
Year(s) Of Engagement Activity | 2016 |
Description | Presentation: Loss and Damage: Perspectives and Options - Boyd, E, James, R, Jones, R |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Policymakers/politicians |
Results and Impact | UN COP22 Marrakech, 7 November 2016, Side Event. Earth Negotiations Bulletin (2016) Coverage of COP22 side event in Marrakesh: "Loss and Damage Perspectives and Options". |
Year(s) Of Engagement Activity | 2016 |
URL | http://enb.iisd.org/climate/cop22/enbots/7nov.html#event-6. |
Description | Presentation: Typologies of Loss and Damage: Insights from an analysis of 40 key stakeholder interviews from science, policy and practice - Boyd, E, James, R, Jones, R |
Form Of Engagement Activity | Participation in an activity, workshop or similar |
Part Of Official Scheme? | No |
Geographic Reach | International |
Primary Audience | Industry/Business |
Results and Impact | Adaptation Futures, Rotterdam, 10 May 2016. |
Year(s) Of Engagement Activity | 2016 |
Description | SBSTA, Bonn |
Form Of Engagement Activity | A talk or presentation |
Part Of Official Scheme? | No |
Geographic Reach | National |
Primary Audience | Policymakers/politicians |
Results and Impact | We performed surveys on members at this meeting to understand the social aspects of loss and damage as seen from a climate change impacts view. A paper is currently in review on this. |
Year(s) Of Engagement Activity | 2014 |