Febrero - 2019
Water scarcity is one of the main problems of irrigation. Future prospects in many arid and semi-arid regions are not very bright, due to global warming. Climate change forecasts point to a significant reduction in available water resources and an increase in the water needs of crops. All of this is due to a general reduction in precipitation, an increase in temperatures, evaporation and evapotranspiration, along with a reduction in aquifer recharge and runoff.
Water is a key element to be taken into account when planning measures to adapt to or mitigate climate change. There is a strong
interrelation between water and energy (water-energy nexus), and between energy consumption and greenhouse gas (GHG) emissions, which are ultimately responsible for climate change. A figure that illustrates this is the average conversion figure of 0.245 kg CO2eq/kWh for 2018 (January to November), released by Red Eléctrica de España. For this reason, rationalisation of water and energy consumption is vital in the fight against climate change.
The extension and intensification of irrigation agriculture brings with it greater (direct and indirect) energy consumption and higher GHG emissions:
• Direct energy consumption is due to labour and electricity consumption (due, above all, to the water-energy nexus) and fuel consumption (mainly by farm machinery). Meanwhile indirect consumption refers to the energy consumed to produce inputs, such as fertilisers, pesticides, seeds, irrigation systems and farm machinery.
• GHG emission sources in agricultural production can be divided into three main categories: (a) GHG emissions associated with the use of fossil fuels and electricity (b) GHG emissions associated with production, transport and storage, and the use of fertilisers and phytosanitary products (c) GHG emissions in the form of NO2 from the soil, due to the application of nitrogenated fertilisers.
Mariano Soto García, Coordinator of the Transfer and Sustainability Chair José Manuel Claver Valderas