When and how will the Millennium Silk Road witness 1.5 °C and 2 °C warmer worlds?

Abstract

Western China and central Asia are positioned centrally along the Millennium Silk Road, which is regarded as a core region bridging the East and the West. Understanding the potential changes in climate over this core region is important to the successful implementation of the so-called ‘Belt and Road Initiative’ (a $1 trillion regional investment in infrastructure). In this study, both mean and extreme climate changes are projected using the ensemble mean of CMIP5 models. The results show a warming of ~1.5, 2.9, 3.6, and 6.0 °C under RCP2.6, 4.5, 6.0, and 8.5, respectively, by the end of the twenty-first century, with respect to the 1986–2005 baseline period. Meanwhile, the annual mean precipitation amount increases consistently across all RCPs, with an increase by ~14% with respect to 1986–2005 under RCP8.5. The warming over the Millennium Silk Road region reaches 1.5 °C before 2020 under all the emission scenarios. The 2020s (2030s) see a 2 °C warming under the RCP8.5 (RCP4.5) scenario. Global warming that is 0.5 °C lower (i.e. a warming of 1.5 °C) could result in the avoidance of otherwise significant impacts in the Silk Road core region—specifically, a further warming of 0.73 °C (with an interquartile range of 0.49%–0.94 °C) and an increase in the number of extreme heat days by 4.2, at a cost of a reduced increase of 2.72% (0.47%–3.82%) in annual precipitation. The change in consecutive dry days is region-dependent.