Abstract
Variations in rainfall patterns, whether in quantity or frequency, pose a significant challenge that sugarcane crops must adapt to in the context of climate change. This study aimed to assess the impact of different future climate scenarios from 2015 to 2100 on sugarcane yield at a regional scale in Réunion Island and to identify adaptation practices to mitigate its impact. Different irrigation regimes were tested to assess the impact on growth and future water requirements using the Mosicas sugarcane crop growth model at a 3 x 3 km resolution. High spatial resolution climate data under three future scenarios of the IPCC (RCP 2.5, 4.5, and 8.5) were obtained from the BRIO project conducted by Météo France, the French national weather service. Results showed that, despite a favorable increase in temperature, the change in precipitation patterns resulted in a minimal change in yield at the island scale (-4 to +2%, depending on the climatic scenarios) compared to the current period. However, the impact of climate change varied significantly across different climatic areas on the island. On the south coast, yields decreased significantly (by -16 and -17% in 2060 and 2090, respectively), while on the east coast at high altitudes, yields increased (by +20% to +39% in 2060 and 2090). Overall, water irrigation demand increased by 15 and 24% in 2060 and 2100, respectively, on average across scenarios. It was found that irrigating non-irrigated areas reduced the negative impact of climate change, particularly in high altitudes in the South and North-East. Additionally, the simulation of more drought-resistant varieties was able to limit the negative impact of climate change in areas facing increasing water deficits without changing the irrigation regime. Finally, this study illustrated how areas currently less suitable for sugarcane production, such as high-altitude areas, will become more favorable as a result of climate change. Adaptation methods such as changes in irrigation management or more drought-tolerant varieties were identified as effective strategies to cope with climate change and maximize the potential of sugarcane in a more favorable temperature environment.