2.4.6.9 Scenario integration

The widespread adoption of SRES-based scenarios in studies described in this report (see Boxes 2.2 to 2.7) acknowledges the desirability of seeking consistent scenario application across different studies and regions. For instance, SRES-based downscaled socio-economic projections were used in conjunction with SRES-derived climate scenarios in a set of global impact studies (Arnell et al., 2004; see Section 2.4.6.4). At a regional scale, multiple scenarios for the main global change drivers (socio-economic factors, atmospheric CO₂ concentration, climate factors, land use, and technology), were developed for Europe, based on interpretations of the global IPCC SRES storylines (Schröter et al., 2005b; see Box 2.7).

Nationally, scenarios of socio-economic development (Kaivo-oja et al., 2004), climate (Jylhä et al., 2004), sea level (Johansson et al., 2004), surface ozone exposure (Laurila et al., 2004), and sulphur and nitrogen deposition (Syri et al., 2004) were developed for Finland. Although the SRES driving factors were used as an integrating framework, consistency between scenario types could only be ensured by regional modelling, as simple downscaling from the global scenarios ignored important regional dependencies (e.g., between climate and air pollution and between air pressure and sea level: see Carter et al., 2004). Similar exercises have also been conducted in the east (Lorenzoni et al., 2000) and north-west (Holman et al., 2005b) of England.

Integration across scales was emphasised in the scenarios developed for the Millennium Ecosystem Assessment (MA), carried out between 2001 and 2005 to assess the consequences of ecosystem change for human well-being (Millennium Ecosystem Assessment, 2005). An SAS approach (see Section 2.4.5) was followed in developing scenarios at scales ranging from regional through national, basin, and local (Lebel et al., 2005). Many differed greatly from the set of global MA scenarios that were also constructed (Alcamo et al., 2005). This is due, in part, to different stakeholders being involved in the development of scenarios at each scale, but also reflects an absence of feedbacks from the sub-global to global scales (Lebel et al., 2005).