Water and food security in a changing planet

With the combination of climate change and population increase, the dependence of the global population on water is more critical than ever. Water is needed for agriculture and water scarcity (droughts) or water excess (floods) can destroy crops. Water plays a key role in the global economy. There has been progress in the areas of hydrology and water resources with predicting the impacts of climate change. Using climate projections, hydrological models can be used to predict future streamflow in river basins. To supplement in-situ observations, there has been numerous advances in remote sensing - to map hydrological variables such as precipitation, vegetation, soil moisture, surface temperature, evapotranspiration and total water at the global scale. Many of these variables can be "observed" at a coarse spatial resolution and more recently there have been a number of methods that can "downscale" these coarse observations. Combining hydrological models and remote sensing observations can help in managing water resources by land use planning. This supplements the in-situ observations of the hydrological cycle that are scarce. Understanding the present-day water cycle can help us plan for the future. The use of combined model-remote sensing methods helps in resolving disputes involving transboundary river basins.