Prominent vegetation greening and its correlation with climatic variables in northern China

Global vegetation has been reported to be turning greener, especially in China and India. The Yellow River Basin is one of the most prominent greening areas in China. While some studies have attributed vegetation greening to large-scale ecological restoration efforts, our study focuses on the role of climate change in vegetation greening. We selected a time series of annual vegetation net primary productivity (NPP) and vegetation coverage from satellite data to quantify the vegetation greening trend. Annual temperature and precipitation were selected to examine the climate trend from 2000 to 2019. The results showed that the Yellow River Basin experienced a rapid increase in temperature and precipitation during this period. Annual temperature increased with an average speed of 0.905 °C per decade, approximately 4.5 times larger than that of global warming. Annual precipitation increased by 82.8%, with an average speed of 9.17 mm per year. There was widespread vegetation greening in the Yellow River Basin during 2000-2019. This was demonstrated by an increase in vegetation NPP and vegetation coverage in the Yellow River Basin. The increase of annual NPP and coverage from 2000 to 1019 was 26.6% and 30.8%, respectively. Even while considering the effects of conservation and restoration efforts, the rapid increases in temperature and precipitation allowed vegetation to flourish, as evidenced by significant positive correlations between climate variables and vegetation variables. Therefore, climate change played an important positive role in vegetation greening, rather than an undesirable disturbance.