Bagher Shirmohammadi

Climate change has increased the vulnerability of arid and semi-arid regions to recurrent and prolonged meteorological droughts. In light of this, our study has sought to assess the nature of future meteorological drought in Lake Urmia basin, Iran, within the context of future climate projections. To achieve this, data from 54 general circulation models (GCMs) was calibrated against both in situ and Global Precipitation Climatology Centre datasets. These GCMs were then employed to project drought conditions expected over 2016–2046 under RCP2.6 and RCP8.5 as the most optimistic and pessimistic scenarios, respectively. To provide a comprehensive analysis, these RCPs were combined with two different time scale Standardized Precipitation Index (SPI), leading to eight different scenarios. The SPI was calculated over two temporal scales for the past (1985–2015) and future (2016–2046), including the medium-term (SPI-6) and long-term (SPI-18) index. Results showed that while precipitation is expected to increase by up to 34%, parts of the basin are projected to face severe and prolonged droughts under both RCPs. The most severe drought event is expected to occur around 2045–2046 under the most pessimistic RCP8.5 scenario. Severe droughts with low frequency are also anticipated to increase under other scenarios. By characterizing meteorological drought conditions for Lake Urmia basin under future climate conditions, our findings call for urgent action for adaptation strategies to mitigate the future adverse effects of drought in this region and other regions facing similar challenges. Overall, this study provides valuable insight into the impacts of climate change on future droughts that can adversely influence water resources in arid and semi-arid regions.

Climate change as an eminent driver of global environmental changes has adversely affected the various dimensions of human life, natural resources, and in particular the flow regimes over the last couple of decades. This study explored the pathways to obtain ecosystem stability and regulate natural processes through incorporating climate change adaptation measures into disaster risk reduction. Accordingly, the hydrological behavior of almost two adjacent similar basins (paired catchments) was assessed in terms of implemented biomechanical measures that served as climate adaptation strategies. The available water stage time series recorded by OTT devices were applied to evaluate the effectiveness of the adaptation measures. Results revealed that the constructed check dams along with the intensified vegetation cover majorly regulated the process of surface runoff generation and its transportation to downstream. The peak flow of 53 and 31 cm were shown across the Control and Treatment catchments, without and with the conservation measures, respectively. The difference in peak flow implies the high contribution of the Control catchment (approximately 41.5%) in surface runoff provision service and flood in particular. Also, the time to peak in the Treatment catchment was 3 times higher than the Control catchment where they touched their own peak 35 and 50 minutes after the rain started, respectively. The findings suggest that biomechanical measures successfully regulated the surface runoff generation which in turn increased the stability of soil to erosion. Therefore, the constructed measures would be strongly recommended as climate mitigation strategies to achieve regional low-impact development as well as environmental sustainability.

Arid and semi-arid regions are more susceptible to climate change impacts, leading to recurrent and sustained meteorological droughts as a natural hazard. Therefore, this study is established to assess the meteorological drought characteristics in the Urmia Lake Basin under a changing climate in Iran. To that end, General Circulation Models (GCMs) were evaluated using observed and Global Precipitation Climatology Centre (GPCC) datasets. Then, the selected GCMs were applied to project drought conditions until 2046 under Representative Concentration Pathway 2.6 and 8.5 (RCP2.6 and RCP8.5). Afterward, we developed eight combined scenarios (A1, A2, A3, A4, B1, B2, B3, and B4) to assess future drought characteristics. Ultimately, the Standardized Precipitation Index (SPI) was calculated using the Drought Indices Package (DIP) for the historic (1985–2015) and future (2016–2046) periods under two temporal scales, namely the medium-term (SPI-6) and long-term (SPI-18). According to the results, precipitation is expected to increase from 16.3–34% while the northeast and south parts of the basin will be affected by future drought effects. The projected SPI-18 under RCP8.5 indicated that the basin will suffer from the most severe and long-standing meteorological drought, anticipated to happen around 2045–2046 (A4 scenario). The increase was projected for severe low-frequency drought events in A4 (long-term) and, B1 and A3 (medium-term) scenarios. While, in most cases, the decrease was shown for the high-frequency with less intensity drought events mainly in medium-term assessment.