The Impact of Climate Change and Climate Extremes on Sugarcane Production

We combine the Soil-Plant-Atmosphere model with detailed timeseries measurements from experimental sugarcane plots in Guangxi, China, and São Paulo State, Brazil. We first calibrated and validated modelled carbon and water cycling against field flux and biometric data. Second, we simulated sugarcane growth under the historical climate (1980-2018), and 6 future climate projections (2015-2100). From these simulations we retrieved modelled sugarcane yield, days to reach maturity, gross primary productivity (GPP), evapotranspiration, PAR incident on the canopy, leaf area index (LAI), and soil water potential (SWP). Next, to quantify the impact of individual climate drivers on sugarcane yield, we generated synthetic climate forcings. Within the historical climate dataset (1980-2018) we computed the mean value for each climate driver, for each year (i.e. temperature, CO2, precipitation, PAR and VPD). For each climate driver, we calculated the median of the annual means. We identified the annual timeseries corresponding to the median for each climate driver. For each climate projection, we substituted, one by one, the temperature, CO2, precipitation, PAR and VPD, with that of the median timeseries. We then ran the model with the new synthetic climate forcings and retrieved the yield, carbon, and water flux estimates for each alternation. For each year, under each climate projection, at each site, we calculated the difference between yield, carbon, and water flux estimates under the projected and alternated-synthetic climate to compute a ‘climate effect’ of each individual climate driver.