Environmental management Climate change 18 Central government policies 11 Sociology 10 Sustainability 10 Ecosystems 8 Environmental science, engineering & technology 8 Applied ecology 6 Forestry 6 Physical geography & topography 6 Sustainable development 6 Carbon dioxide 5 Conservation of the environment 5 Energy technology & engineering 5 Environmental impact 5 Environmental performance 5 Environmental policy & protocols 5 Life cycle 5 Biodiversity 4 China 4 Ecological science, the Biosphere 4 Environmental economics 4 Land use 4 Decision making 3 Development studies 3 Environmental sustainability 3 Environmental technology 3 Global warming 3 Greenhouse gases 3 Indicator indicator 3