Mitigation of greenhouse gas emissions and nitrogen losses caused by migration and tourism in China's tropical island cities.

Islands worldwide face escalating ecological challenges from increasing migration and tourism. These pressures significantly contribute to transgression of Earth's ecosystem boundaries (ESBs). This study focuses on Hainan Island, a tropical region whose 18 cities reflect global island-ecosystem dynamics. It illuminates a global scenario: human activities disproportionately affect islands with 86 % of the global population impacted by regional transgression of Earth's ecosystem boundaries. The results show a 4.8-fold increase in greenhouse gas emissions (GHG) from domestic activities and a 12-fold surge in tourism-related emissions from 2000 to 2019. These findings underscore the urgent need for sustainable development strategies. Environmental costs were evaluated against tourism profits in this study, revealing critical trade-offs between economic benefits and ecological preservation. The implications extend beyond Hainan Island, calling for a global dialogue on the sustainable management of island ecosystems, especially in the face of climate change.