## 2 Data and Methods
### Data
#### 2.1.3 Climate Change Impacts  
The Inter-Sectoral Impact Model Intercomparison Project (ISIMIP) addresses climate impacts in a range of systems and sectors such as health, coastal infrastructure, and forests and other ecosystems. The first ISIMIP simulation round, the ISIMIP Fast Track, had a focus on providing cross-sectorally consistent projections of the impacts of different levels of global warming in the 21 st century. The common set of scenarios made use of climate projections from five global climate models (GCMs) driven by the recommended concentration pathways (RCPs), making ISIMIP a natural extension of the work done within the Coupled Climate Model Intercomparison Project (CMIP) [35]. ISIMIP2a includes modeling intercomparison efforts in fisheries, permafrost, biodiversity, regional water, forests, and energy, as well as those sectors already covered in the Fast Track. This serves as a basis for model evaluation and improvement, allowing for improved estimates of the biophysical and socio-economic impacts of climate change at different levels of global warming [36]. ISIMIP2b is designed to provide robust information about the impacts of 1.5 \({}^{\circ}\)C global warming and related low-emission pathways [37; 38]. In this paper, we used the simulation data of crops yield and water resources provided by ISIMIP2a. In the present work, the focus was on impacts of surface freshwater availability and crop yields since these factors are likely to have the greatest direct impacts on the livelihoods life and development of population [39]. Both factors were modeled using the global gridded biosphere model LPJmL [40; 41]. The model LPJmL (\"Lund-Potsdam-Jena managed Land\") was designed to simulate vegetation composition and distribution, as well as stocks and land-atmosphere exchange flows of carbon and water, for both natural and agricultural ecosystems. Using a combination of plant physiological relations, generalized empirically established functions, and plant trait parameters, it simulates processes such as photosynthesis, plant growth, maintenance and regeneration losses, fire disturbance, soil moisture, runoff, evapotranspiration, irrigation, and vegetation structure [42; 43; 44]. Annual crop yields are simulated for each of the four major crops (maize, wheat, rice, and soy beans) and for rain-fed and irrigated cultivation assuming crop growth on all land grid cells [45]. These yields are weighted by each cell's corresponding growing area around the year 2000. The resulting index has units of production (tons per hectare), but its variability represents yield variability because the growing areas are static. The weighted yield indices for all four crops are summed to obtain an overall yield index that is comparable across countries (assuming that these four crops represent, in both countries, the majority of crops produced). Water availability is represented by monthly river flow (discharge) averaged over each year. Importantly, the simulations do not take into account any water withdrawals for human use (such as irrigation) or any other human-induced changes to the water cycle. This means that any changes over time in simulated water availability can be attributed to changes in weather patterns. The model is driven by two different climate reanalysis datasets to account for potential uncertainties in climate reconstructions: the Global Soil Wetness Project phase 3 forcing dataset (GSWP3) [46] ([[http://hydro.iis.u-tokyo.ac.jp/GSWP3/](http://hydro.iis.u-tokyo.ac.jp/GSWP3/)]([http://hydro.iis.u-tokyo.ac.jp/GSWP3/](http://hydro.iis.u-tokyo.ac.jp/GSWP3/))), based on the 20 th century reanalysis (20 CR), and the Princeton Global Forcing dataset version 2 (PGFv2) [47], based on NCEP/NCAR reanalysis (The NCEP/NCAR Reanalysis data set is a continually updated (1948-present) globally gridded data set that represents the state of the Earth's atmosphere, incorporating observations and numerical weather prediction (NWP) model output from 1948 to present.