Food security and global security - IEEE

María del Mar Hidalgo GarcíaThe impact of climate change on food securityfungi as wind patterns change, leading to the appearance of emerging andre-emerging illnesses, and an increase in the severity of pathogens (17) .■■Water SupplyIrrigated crops account for 20% of cultivated land globally, but for 40% ofthe food produced (18) . In these cases, the water used is drawn from rivers; as aresult availability depends on weather in remote areas. One example of this isagriculture along the length of the Nile, which depends on rainfall in its higheststretch in Ethiopia.68In other regions, river flows depend on ice melting. In medium and highlatitudes, mild winters result in lower precipitation in the form of snow, resultingin reduced water flow in spring. Almost a sixth of the world’s population livesaround the Ganges and Indus river basins, using their waters for domesticand agricultural purposes. Both rivers depend on melting of glaciers in themountains, and this in turn is being influenced by global warming. Thisphenomenon may result in seasonal flows in both rivers, decreasing in thedry season and increasing in the rainy season with greater risks of flooding.Combined with increasing populations in the area, this could result in watershortages in future.In other situations, water shortages are not due to low rainfall, but to surfacerun off, evaporation and deep percolation (19) .■■Rising Sea LevelsRising sea levels are an inevitable consequence of climate change. There aretwo main reasons for this increase: thermal expansion of the oceans and anincrease in the mass of water due to ice melting from warming. Although theseeffects should be taken into account at present, they are not expected to occurin the short term, given the rate of ice melting in the major ice shelves atpresent. The fourth IPCC report estimates that sea levels could rise by between0.1 m and 0.5 m.The most vulnerable regions to such changes are those in river deltas and islandstates in South-East Asia, which could suffer flooding of crops and salinationof underground water sources.(17)Rosenzweig, C. and D. Hillel. «Climate change and the global harvest: potential impacts ofthe greenhouse effect on agriculture. Oxford University Press, New York.(18)Döll, P and Siebert, S. Global modeling of irrigation water requirements. Water Resour.Res. 38.(19)Altieri, M and Nicholls, C. «Cambio climático y agricultura campesina: impactos yrespuestas adaptativas». University of California, Berkeley, USA.