Potential impact projection does not include adaptation of actors in projecting impacts. Impact projection methods analyse the possible impact of climate change and other potential drivers on a study unit. The fundamental theoretical assumption of impact analysis is that it is possible to analytically distinguish between a study unit and its (natural and socio-institutional) environment in the sense that the environment influences the study unit but whatever happens "inside" the study unit does not feed back on its environment. This separation allows for the representation of the evolution of the environment in form of a set of scenarios that are independent from the model used to represent the study unit. If changes in the study unit would influence the environment, than an integrated (assessment) model would need to be used for representing both the study unit and its environment together. We follow the IPCC in distinguishing methods that analyse potential impacts, which are those that "may occur without considering adaptation" (Parry et al. 2007: 876), in opposition to methods that assess residual impacts, which include adaptation. One problematic aspect about potential impact assessments is that the theoretical assumption made that people don't adapt is often empirically rather unlikely to be met. The potential impact that "many millions more people are projected to be flooded every year due to sea-level rise by the 2080s", reported in the AR4 WG2-SPM (IPCC 2007), for example, is rather unrealistic because this would assume that people continue to live in the coastal zone even though they experience frequent flooding or even permanent inundation (Hinkel 2011b).
What are the impacts of climate change ?
Interaction between the drivers and the study unit can be formally represented as a computational model.
People affected do not adapt.
1. Selection of climate and socio-economic scenarios 2. Computation of the potential impacts of those scenarios 3. Evaluation of impacts using impact indicators
A list of propositions that map each scenario to an impact. Each proposition is interpreted in the following way: 'When the world evolves according to scenario e and people don't adapt, the impact on will be i'.
Rarely understood that potential impacts will almost certainly not occur because adaptation will take place. E.g., people living in the coastal zone are likely to move away before experiencing permanent flooding.
Dasgupta et al. (2007) address the question of what the impacts of sea-level rise are on developing countries are. Impacts are projected for sea-level rise scenarios of 1 to 5 meter by overlaying data on land, population, agriculture, urban extent, wetlands and GDP with the inundation zones of the sea-level rise scenarios. They find that tens of millions of people will be displaced and economic damages will be severe but limited to a couple of countries
Read more in the Toolbox under the following category:
Modelling future impacts |
Toolbox detail page(s) available for:
Case study steps identified for task 'Potential impact projection'.
weADAPT case studies identidied for task 'Potential impact projection' 1
Climate change modelling and analyses for Mozambique
This report uses historical data and climate projections to assess how climate change may affect the operations of Mozambique's Instituto Nacional de Gestão de Calamidades (National Disaster Management Institute)... | |
Impact of sea-level rise on the city of Banjul
Impact of 1m sea-level rise on Banjul. Banjul is located on a low-lying spit composed entirely of erodable sediments, and is already experiencing problems due to coastal erosion. Studies show that the majority of the city would be inundated under a 1m rise in sea-level due to the very low-lying nature of the city, as shown in the graphic below (Jallow et al 1996).... | |
Sea-Level Rise and Impacts in Africa, 2000 to 2100. Application of the DIVA model to Africa.
United Nations Environment Programme (UNEP): AdaptCost project.
| |
1 note that this does not imply that the Mediation Integrated Methodology was used in these cases. |
This section is based on the UNEP PROVIA guidance document |
1. | You want to assess vulnerability. | |
2. | Your focus is on impacts. | |
3. | Either no studies on future impacts are available, or available studies are not comprehensive or credible. | |
4. | Impact models are available that can be used to simulate future impacts. | |
5. | Adaptation should not be included in the projection. |
Available related training material
WEAP
Training material for WEAP |