The impact of weather and increased atmospheric CO ₂ from 1892 to 2016 on simulated yields of UK wheat

Climate change effects on UK winter wheat grain yield are complex: warmer temperature, negative; greater carbon dioxide (CO 2 ) concentration, positive; but other environmental variables and their timing also affect yield. In the absence of long-term experiments where temperature CO concentration were manipulated separately, we applied crop simulation model Sirius with daily meteorological data (1892–2016) for Rothamsted, Hertfordshire, (2007–2016 mean growing season 1.03°C than 1892–1991), over this period, to investigate separate historic weather simulated in three cultivars modern era. We show a slight decline period 1892–2016 from effect (daily rainfall sunshine hours) at fixed (294.50 ppm, 1892 reference value), maximum 9.4% increase when accounting increasing atmospheric (from 294.50 404.21 ppm), differing slightly among cultivars. Notwithstanding considerable inter-annual variation, ppm 125-year simulations Rothamsted agrees expected alone, positive trend actual values does not match recent stagnation