Highly suitable areas for tea (Camellia sinensis) production will decline under future climate change scenarios

Tea [Camellia sinensis (L.) O. Kuntze], one of the most widely consumed beverages globally, is cultivated on over 5.27 million ha of land, is a source of income for low-income families. However, the effect of future emission scenarios on the suitability of areas for tea production is poorly understood, and any adverse outcome under climate change scenarios can affect millions of households and the tea industry. We assess the current and future habitat suitability of tea across the globe under two shared socio-economic pathways (SSPs = SSP2.4-5 and SSP5.8-5) for 2050 and 2070 and determine the key factors that influence tea distribution. We employed an ensemble of five species distribution models to assess the tea distribution. Overall, the highly suitable areas for tea production will experience some decline in 11 out of the top 20 tea-producing countries by 2050 and 2070 under both SSP2-4.5 (moderate emission scenarios) and SSP5-8.5 (high emission scenarios) relative to the current conditions. However, marginally suitable areas will increase by 39 % by 2050 and 72 % by 2070 under the high-emission scenario. Some tea-producing countries such as Argentina, Malawi and Tanzania are projected to experience a 60-78 % reduction of their highly suitable area for tea, while Iran, Rwanda, Thailand, and Turkey will witness an 11-27 % increase by 2050. Precipitation of the warmest quarter, mean temperature of the driest quarter, soil pH, isothermality, and mean temperature of the wettest quarter are the key variables influencing the current distribution of tea. Here, we provide projections of changes in the highly suitable area for the top 20 tea-producing countries in the world by 2050, which we hope will serve as baseline information for decision-makers to make evidence-informed choices. Since the present study was performed at a coarse scale, it is strongly recommended that future studies produce fine-scale projections with regional climate and ground-truth tea production data.