Browsing by Subject "CHANGE SCENARIOS"

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  • Montaldo, Nicola; Oren, Ram (2018)
    Over the past century, climate change has been reflected in altered precipitation regimes worldwide. Because evapotranspiration is sensitive to both water availability and atmospheric demand for water vapor, it is essential to assess the likely consequences of future changes of these climate variables to evapotranspiration and, thus, runoff. We propose a simplified approach for annual evapotranspiration predictions, based on seasonal evapotranspiration estimates, accounting for the strong seasonality of meteorological conditions typical of Mediterranean climate, still holding the steady state assumption of basin water balance at mean annual scale. Sardinian runoff decreased over the 1975-2010 period by more than 40% compared to the preceding 1922-1974 period. Most of annual runoff in Sardinian basins is produced by winter precipitation, a wet season with relatively high evaporation rates. We derived linear seasonal evapotranspiration responses to seasonal precipitation, and, in turn, a relationship between the parameters of the linear functions and the seasonal vapor pressure deficit (D), accounting for residuals with basin properties. We then used these relationships to predict evapotranspiration and runoff using future Intergovernmental Panel on Climate Change climate scenarios, considering changing precipitation and D seasonality. We show that evapotranspiration is insensitive to D scenario changes. Although both evapotranspiration and runoff are sensitive to precipitation seasonality, future changes in runoff are related only to changes of winter precipitation, while evapotranspiration changes are related to those of spring and summer precipitation. Future scenario predicting further runoff decline is particularly alarming for the Sardinian water resources system, requiring new strategies and designs in water resources planning and management.
  • Landreau, Armand; Juhola, Sirkku; Jurgilevich, Alexandra; Räsänen, Aleksi (2021)
    The assessments of future climate risks are common; however, usually, they focus on climate projections without considering social changes. We project heat risks for Finland to evaluate (1) what kind of differences there are in heat vulnerability projections with different scenarios and scales, and (2) how the use of socio-economic scenarios influences heat risk assessments. We project a vulnerability index with seven indicators downscaled to the postal code area scale for 2050. Three different scenario sets for vulnerability are tested: one with five global Shared Socioeconomic Pathways (SSPs) scenarios; the second with three European SSPs (EUSSPs) with data at the sub-national scale (NUTS2); and the last with the EUSSPs but aggregated data at the national scale. We construct projections of heat risk utilizing climatic heat hazard data for three different Representative Concentration Pathways (RCPs) and vulnerability and exposure data for five global SSPs up to 2100. In the vulnerability projections, each scenario in each dataset shows a decrease in vulnerability compared to current values, and the differences between the three scenario sets are small. There are evident differences both in the spatial patterns and in the temporal trends when comparing the risk projections with constant vulnerability to the projections with dynamic vulnerability. Heat hazard increases notably in RCP4.5 and RCP8.5, but a decrease of vulnerability especially in SSP1 and SSP5 alleviates risks. We show that projections of vulnerability have a considerable impact on future heat-related risk and emphasize that future risk assessments should include the combination of long-term climatic and socio-economic projections.