Climate change impact on water resources and crop production in Armenia

Abstract

Agricultural sector of small, mountainous country Armenia is very vulnerable towards climate change, due to frequent drought episodes, enhanced air temperature, reduced precipitation, increased evaporation rates and water scarcity. To maximize the crop production in a country with specific economic structure, where 21% of GDP is formed in the agricultural sector, it is necessary to estimate the capacity of agrometeorological and water resources, effectiveness of irrigation amounts under the current and future climate conditions, which is the main aim of the given study.Armenian State Hydrometeorological Service provided the data on meteorology (air temperature, precipitation, relative humidity, wind speed and direction) for 30 stations distributed evenly over the whole territory of the republic during the time period of 1966–2010. For interpolation of climate variables within the region, climate of the South Caucasus has been modeled firstly for the current situation with the mesoscale METRAS model (Mesoscale Transport and Stream) with 12km spatial resolution. Later on, based on General Circulation Models (GCMs) climate projections for the near future (until 2040) have been realized showing significant increase in average air temperature by 1.6K, but no reliable changes in precipitation sum; still dryness is obvious in the region.Further agrometeorological parameters (potential and actual evapotranspiration, soil temperature and humidity) have been assessed applying AMBAV model (Agrarmeteorologisches Modell zur Berechnung der aktuellen Verdunstung) developed by German Weather Service in Braunschweig. The analysis showed that there is a significant difference in meteorological and hence, also in drought conditions (large differences in soil temperature and humidity, as well as the evapotranspiration sums) among dry and hot western states and relatively cold and humid northern states, which has a direct influence on potential and actual yield ratio.Further the results of the model have been used in order to assess crop water irrigation requirements in the country utilizing crop development coefficients for various crop types at different growing stages in order to organize water management and irrigation systems efficiently. It was estimated that for each hectare 3000m3 water is required in current climate conditions, which will be nearly doubled in future in regard to climate change. This irrigation assessment for the entire country has been carried out for the first time allowing not only the farmers, but also the government to meet the new millennium challenges under climate change convention.