Abstract
The continuous increase of atmospheric CO2 content mainly due to anthropogenic CO2 emissions is causing a rise in temperature on earth, altering the hydrological and meteorological processes and affecting crop physiology. Evapotranspiration is an important component of the hydrological cycle. Thus, understanding the change in evapotranspiration due to global warming is essential for better water resources planning and management and agricultural production. In this study, the effect of climate change with a focus on the combined effect of temperature and elevated CO2 concentrations on reference evapotranspiration (ETo) was evaluated using the Penman–Monteith equation. A EURO-CORDEX regional climate model (RCM) ensemble was used to estimate ETo in five locations in the Emilia-Romagna region (Northern Italy) during the period 2021–2050. Then, its projected changes in response to different CO2 concentrations (i.e., 372 ppm and 550 ppm) under two Representative Concentration Pathways (RCP) scenarios (i.e., RCP4.5 and RCP8.5) were analyzed. Simulation results with both scenarios, without increasing CO2 levels (372 ppm), showed that the annual and summertime ETo for all locations increased by an average of 4 to 5.4% with regard to the reference period 1981–2005, for an increase of air temperature by 1 to 1.5 °C. When the effect of elevated CO2 levels (550 ppm) was also considered in combination with projected changes in temperature, changes in both annual and summer ETo demand for all locations varied from − 1.1 to 2.2% during the 2021–2050 period with regard to the reference period 1981–2005. This shows that higher CO2 levels moderated the increase in ETo that accompanies an increase in air temperature.
Highlights
The increase of anthropogenic emissions of carbon dioxide (CO2) and other radiatively active gases, due to activities such as fossil fuel combustion and deforestation, is one of the most prominent causes of climate change (Hamza et al 2020)
The aim of this paper was to assess the effect of climate change on crop reference evapotranspiration in five locations in the Emilia-Romagna region during the near future period 2021–2050, with a focus on the effects of higher CO2 levels and agrometeorological parameters on ETo
The comparison made against data observations for the period 2008–2018 gave satisfying results, allowing the reanalysis dataset to be used as a long-term reference dataset
Summary
The increase of anthropogenic emissions of carbon dioxide (CO2) and other radiatively active gases, due to activities such as fossil fuel combustion and deforestation, is one of the most prominent causes of climate change (Hamza et al 2020). The relentless rise of CO2 concentrations will most probably influence water fluxes and resources at both local and global scales (Haddeland et al 2014) This effect will be intensified by the projected increases in global surface air temperature (IPCC 2013) leading to an uneven distribution of water resources and causing several problems in water availability (Estrela et al 2012; Boehlert et al 2016; Akbarpour and Niksokhan 2018). This is especially true in the Mediterranean region as it has shown large climate shifts in the past and it has been identified as one of the most prominent “hot spots” in future climate change projections, with an expected greater than average warming, mostly in summer, and an increase of heat waves and dry spells (Olesen and Bindi 2002; Giorgi and Lionello 2008).
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
