In a meta-analysis we integrate peer-reviewed studies that provide quantified estimates of future projected ecosystem changes related to quantified projected local or global climate changes. In an advance on previous analyses, we reference all studies to a common pre-industrial base-line for temperature, employing up-scaling techniques where necessary, detailing how impacts have been projected on every continent, in the oceans, and for the globe, for a wide range of ecosystem types and taxa. Dramatic and substantive projected increases of climate change impacts upon ecosystems are revealed with increasing annual global mean temperature rise above the pre-industrial mean (?Tg). Substantial negative impacts are commonly projected as ?Tg reaches and exceeds 2°C, especially in biodiversity hotspots. Compliance with the ultimate objective of the United Nations Framework Convention on Climate Change (Article 2) requires that greenhouse gas concentrations be stabilized within a time frame "sufficient to allow ecosystems to adapt naturally to climate change". Unless ?Tg is constrained to below 2°C at most, results here imply that it will be difficult to achieve compliance. This underscores the need to limit greenhouse gas emissions by accelerating mitigation efforts and by protecting existing ecosystems from greenhouse-gas producing land use change processes such as deforestation

This paper describes the development and first results of the "Community Integrated Assessment System" (CIAS), a unique multi-institutional modular and flexible integrated assessment system for modelling climate change. Key to this development is the supporting software infrastructure, SoftIAM. Through it, CIAS is distributed between the communities of institutions which has each contributed modules to the CIAS system. At the heart of SoftIAM is the Bespoke Framework Generator (BFG) which enables flexibility in the assembly and composition of individual modules from a pool to form coupled models within CIAS, and flexibility in their deployment onto the available software and hardware resources. Such flexibility greatly enhances modellers' ability to re-configure the CIAS coupled models to answer different questions, thus tracking evolving policy needs. It also allows rigorous testing of the robustness of IA modelling results to the use of different component modules representing the same processes (for example, the economy). Such processes are often modelled in very different ways, using different paradigms, at the participating institutions. An illustrative application to the study of the relationship between the economy and the earth's climate system is provided

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Climate change is expected to cause significant changes in the future distribution of precipitation, as well as in the frequency and intensity of high and low rainfall events across the world. In particular, there is an expectation of drying in southern Europe and wetting in northern Europe, with some regions such as southern UK experiencing drier summers and wetter winters. In this study, a community integrated assessment system (CIAS) is used to project the impacts of climate change associated with various emissions scenarios and in particular to demonstrate the extent to which climate mitigation policy might reduce the projected changes in drought regime for Europe under climate change scenarios over the 21st century. Components of CIAS include a simple climate model, MAGICC, and a spatial climate scenario generator, ClimGen, tuned to emulate 3 global general circulation model behaviours and climate change patterns. In baseline (no mitigation policy) cases, very large increases in drought are projected for southern Europe. However, stringent mitigation policy, in which CO 2 concentrations stabilize at 450 or 400 ppm, produces very large reductions in both drought frequency and in total months of drought which would otherwise be experienced during 2050 to 2099, regardless of the global circulation model used to project the patterns of climate change across Europe. The study also illustrates a possible range of future drought scenarios which adaptation planners across Europe need to consider. ) driven by 2 alternative GCMs. Blenkinsop & Fowler (2007a,b) and Frei et al. (2006) projected future changes in drought characteristics based on the SRES A2 emissions scenario only (Nakicenovich & Swart 2000) whilst Beniston et al. (2007) used A2 and B2 SRES scenarios. Leh ner et al. (2006) simulated future European drought using a model named WaterGAP driven by the inputs of 2 alternative GCM patterns from HadCM3 and ECHAM4, considering 2 no-climate policy baselines including IS92a in which CO 2 concentrations in crease by 1% annually (IPCC 1994). Ensemble-based probabilistic projections exist for changes in European extreme precipitation (Palmer & Ralsanen 2002) for the period 2060-2080, again for IS92a, and for daily precipitation and hydrology in the UK (New et al. 2007) for doubled CO 2 concentrations. Re cent global, but regionally specific, studies have improved on these earlier studies by using a wider range of GCMs (Sheffield & Wood 2008; Hira ba yashi et al. 2008, Planton et al. 2008) but focus on 1 to 3 emissions scenarios only. None of these studies examine the implications of higher emissions of the SRES A1 fossil intensive scenario (A1FI). The present study builds on this existing work by (1) including, for the first time, the study of scenarios which include climate policy (i.e. policy-induced reductions in emissions of greenhouse gases, commonly referred to as mitigation); (2) calculating, for the first time, the benefits of the mitigation: specifically, by quantifying the reductions in pro...