دانلود رایگان مقاله عدم اطمینان در تاثیر تغییرات آب و هوایی بر منابع آب

ABSTRACT

The uncertainty concepts play a prominent role in global environmental change research, including climate change science and climate change impact science, with hydrology and water resources research in particular. One is uncertain, to varying degrees, about virtually everything in the future as well as about much of the past and the present state. The present paper reviews applications of the uncertainty notion to results of change detection, process understanding and modeling of systems, and – foremost – projections of future climate change impacts on water resources. We present a framework of assessing and reducing uncertainty and propose measures that could improve uncertainty communication, e.g. relying on ensembles and multi-model probabilistic approaches rather than projecting ranges of values. We distinguish two possible management strategies if uncertainty is irreducible – the precautionary principle and the adaptive management.

7. Concluding remarks

Present comprehension of climate change and its past, present, and future impacts on water resources generally suffers from strong uncertainties because of the gaps in knowledge and insufficient understanding of the complex processes and their feedbacks and interconnections (cf. Funtowicz and Ravetz,1990).

Even if the stock of knowledge increases with time, we find factors that were ignored earlier, hence the uncertainty may also grow. It also seems to grow if we use multi-model ensembles that lead to different simulations, instead of single models.

Remarkable uncertainty of climatic input comes on top of the “traditional” uncertainty existing in hydrology, related to portraying links between variables, choice of model structure, parameterization and parameter estimation. We reviewed metrics for representing the degree of uncertainty and demonstrated how uncertainty can be reduced.

There are many sources of uncertainty in projections for the future, discussed in this paper. Using ensembles of climatic and hydrological models may allow to find more robust results, supported by several models, for some river basins or regions. But, at the same time it can result in large spread of simulations in other regions, and even different directions of change that are difficult to interpret using current tools.

There exists an opinion that decision making should be postponed until sufficient knowledge becomes available (wait-and-see stance). However, as noted by Refsgaard et al. (2013), in some contexts even large uncertainties may imply small consequences for decision making – there can be sufficient knowledge to justify action in climate adaptation.