Event

During the development phase, the IPCC expert meeting on “Toward New Scenarios for Analysis of Emissions, Climate Change, Impacts, and Response Strategies”, held in Noordwijkerhout, The Netherlands (19–21 September, 2007), called for the organization of a meeting of the IAM and impact and adaptation communities to develop a joint strategy for storyline development. The need for such a workshop was reiterated by the Task Group established by the IPCC during its 30th session in Antalya, Turkey (21-23 April, 2009) to facilitate the catalytic role of the IPCC. 

With the RCPs, climate model simulations are envisioned to be complemented by a “library of socioeconomic scenarios and storylines” to inform impacts and adaptation analyses and IAM emission trajectories in ways that are mutually consistent. While each RCP was generated by an IAM driven by a set of assumptions about future socioeconomic development, technology, and policy, many other alternative sets of assumptions could result in the same concentration/radiative forcing pathway. This flexibility is an intentional and innovative feature of the RCP process. However, the assumptions chosen can significantly affect the outcomes of impacts and adaptation projections and analyses. Consistent scenario definitions of baseline and mitigation scenarios are critical to ensure comparability across studies that will be assessed in the IPCC AR5; this process needs to be initiated soon. An IPCC Workshop involving the relevant communities engaged with the scenario development is necessary to address these issues.

An important feature of the upcoming 5th IPCC Assessment Report (AR5) will be improved coherence across the IPCC Working Groups under new scenarios of projected climate change and its impacts, the degree to which adaptation and mitigation policies could reduce climate change and its impacts, and the costs of action and inaction. 

The overall aim of the workshop is laid down in the Noordwijkerhout report (II.3.2 – New IAM scenarios). In detail this includes:

1. Development of consistent sets of baseline and mitigation scenarios that allows for an assessment of all relevant mitigation and adaptation options. Therefore, baseline and mitigation scenarios will be analyzed in terms of

impacts, adaptation needs and mitigation requirements. These alternative scenarios should cover and lay open the reasonable range of socioeconomic, technological and climate science assumptions and employ the RCPs as benchmark scenarios.

2. Identify the most crucial socio-economic uncertainties and underlying assumptions relevant for baseline as well as mitigation scenarios, such as demographic development, land-use changes, technological change, macroeconomic

growth and trade patterns.

3. Exploring a number of (mitigation) scenarios which take into account more “real world” mitigation scenarios like the limited availability of certain technologies, delayed participation of crucial countries, sub-optimal design of

policy instruments like taxes and emission trading schemes as well as other barriers of implementation.

4. Outline a valid, robust, and consistent approach across the IAM and IAV communities to employing these alternative scenarios that characterize and frame different possible futures in each set of baseline and mitigation

scenario.

5. Extract and identify a minimum set of illustrative quantitative socioeconomic trajectories that can be clustered to develop narrative storylines relevant to IAV and IAM ex-post analyses.