10.8 Key uncertainties, research gaps and priorities

10.8.1 Uncertainties

The base for future climate change studies is designing future social development scenarios by various models and projecting future regional and local changes in climate and its variability, based on those social development scenarios so that most plausible impacts of climate change could be assessed. The emission scenarios of greenhouse gases and aerosols are strongly related to the socio-economics of the countries in the region and could be strongly dependent on development pathways followed by individual nations. Inaccurate description on future scenarios of socio-economic change, environmental change, land-use change and technological advancement and its impacts will lead to incorrect GHG emissions scenarios. Therefore factors affecting design of social development scenarios need to be examined more carefully to identify and properly respond to key uncertainties.

The large natural climate variability in Asia adds a further level of uncertainty in the evaluation of a climate change simulation. Our current understanding of the precise magnitude of climate change due to anthropogenic factors is relatively low, due to imperfect knowledge and/or representation of physical processes, limitations due to the numerical approximation of the model’s equations, simplifications and assumptions in the models and/or approaches, internal model variability, and inter-model or inter-method differences in the simulation of climate response to given forcing. Current efforts on climate variability and climate change studies increasingly rely upon diurnal, seasonal, latitudinal and vertical patterns of temperature trends to provide evidence for anthropogenic signatures. Such approaches require increasingly detailed understanding of the spatial variability of all forcing mechanisms and their connections to global, hemispheric and regional responses.

Uncertainty in assessment methodologies per se is also one of the main sources of uncertainty. In model-based assessments, results on impacts of climate change, in fact, accumulate errors from the methodologies for establishment of socio-economic scenarios, environmental scenarios, climate scenarios and climate impact assessment (Challinor et al., 2005).