Climate change Vegetation 6 China 5 Northern Hemisphere 5 Northern Hemispheres 5 climate change 5 Climate models 4 Land use 4 NDVI 4 human activity 4 Human activities 3 MODIS 3 Vegetation greening 3 land cover 3 Climate factors 2 Correlation methods 2 Deterioration 2 Earth system models 2 Ecology 2 Ecosystems 2 Glacial geology 2 Human impact 2 Lakes 2 Late Holocene 2 Machine learning 2 Machine-learning 2 Normalized difference vegetation index 2 Northern China 2 Northern Iran 2 Reforestation 2