Implications of climate change on crop water requirements in arid region: An example of Al-Jouf, Saudi Arabia

This study investigated possible implications of climate change on crop water requirements (CWRs) from 2011 to 2050 in Al-Jouf, Saudi Arabia. CWR were predicted for four scenarios: (i) current temperature and rainfall (S1); (ii) temperature in 2050 and current state of rainfall (S2); (iii) rainfall in 2050 and current state of temperature (S3) and (iv) temperature and rainfall in 2050 (S4). Assuming no change in the regulations relating to agriculture and irrigation in future, CWR were predicted to be 873 and 931 million cubic meters (MCM) per year for the S1 and S4 scenarios, respectively, indicating an increase of 58 MCM from 2011 to 2050. On an average, 1 °C increase in temperature may increase the overall CWR by 2.9% in this region. Following linear pattern of increase, slope of CWR was determined as 1.5 MCM/year from 2011, which is equivalent to the CWR of producing approximately 600 tons of wheat/year. The increase of CWR was due to the increase in temperature mainly, while the effect of rainfall changes was minimal. Sensitivity analysis on crop growing seasons showed that the shift of wheat growing season might conserve significant amount of groundwater. This study might be useful in explaining the negative effects of climate change on CWR in Al-Jouf and better planning for water resources management.