Greenness and averted mortality in 390 cities in China (2000-2020).

BACKGROUND

China's growth over recent decades rapidly transformed the urban landscapes. Green spaces provide numerous health benefits including acting as nature-based solutions for climate change risks. Our study aims to track greenness trends in urban areas in China and quantify the health impact of greenness on adult mortality.

METHODS

In China, we mapped the urban human population distribution aged 20 and above with a 1 km grid (30 arc-second) and used satellite-based remote sensing to measure green space over time to create population-weighted normalized difference vegetation index (NDVI). We tracked changes in greenness in the urban area over time and created a spatial-temporal map. Based on counterfactual scenarios, we calculated averted deaths attributed to NDVI changes from 2000 to 2020.

FINDINGS

We analyzed and mapped 390 cities or urban areas in China, covering an urban population of nearly 500 million. We found population-weighted NDVI exhibiting an overall increase from 2000 to 2020 for most cities. Our analysis calculated urban areas that experienced decrease in urban NDVI from 2000 to 2010 could have had an estimated 9951 additional deaths annually (95% CI: 3346-18,106), while increase in NDVI from 2010 to 2020 could have averted an estimated 37,653 deaths annually (95% CI: 26,327-60,135). If the NDVI were increased to the target level in 2000 and 2010, the number of deaths would be reduced by 110,976 (95% CI: 82,010-171,561) and 118,330 (95% CI: 87,362-183,283), respectively.

INTERPRETATION

Greenness has increased in most urban in China since 2000. Considering the ongoing impacts of climate change and urbanization, sustained efforts in greenness management could serve as an effective resilience factor for protecting population health.

FUNDING

Natural Science Foundation of Beijing (IS23105), National Natural Science Foundation of China (82250610230, 72061137004), World Health Organization (2024/1463606-0), Research Fund Vanke School of Public HealthTsinghua University (2024JC002).