Agriculture and Water
The planet’s hydrologic cycle will accelerate as the rate of evaporation increases due to rising temperatures. In the tropics and regions at higher latitudes, rainfall is predicted to increase. The opposite will occur in areas that are already semi-arid and dry. Rainfall will continue to decline in these regions and in the interiors of large continents. Areas that already suffer from water scarcity are projected to become even more hot and dry, and the frequency of droughts around the world is predicted to increase.
Glaciers around the world are melting due to global warming. In Argentina, for example, Patagonian glaciers have receded by 1.5 kilometers in just 13 years. In the Alps, entire glaciers have completely disappeared in 40 years. Glaciers provide water for 40 percent of the world’s irrigation, and their loss could have a dire impact on the availability of surface water used for agriculture in some areas.
While increased temperatures will extend the growing season in temperate northern areas, the season will be shorter throughout the rest of the world. Warmer temperatures will also cause an increase in evapotranspiration, the sum of water that enters the atmosphere due to evaporation and plant transpiration. More rapid evapotranspiration will reduce the water productivity and yield potential of crops. To provide future food security to at-risk populations, the FAO encourages countries to become more accountable for their agriculture and water practices. For instance, nations must have effective systems to monitor and measure water supplies and create plans to foster more sustainable use.
Individual farmers can cope with the agriculture and water changes brought about by global warming by planting crops earlier or later in the season, optimizing irrigation and using less water. Adopting soil moisture conservation techniques increases crop productivity and yield. Although adopting these changes may be difficult for farmers with little capital, the alterations will soon become necessary to continue producing crops in the face of climate change.
Although scientists still do not fully understand the relationship between climate change, agriculture and water, it is clear that global warming will have a significant effect on farmers across the world.