Climatic changes Environmental aspects 203 Environmental sciences 122 Government policy 104 Global warming 93 Geography 73 Sustainable development 73 Economic aspects 60 Social aspects 59 Environmental policy 49 Life sciences 48 Environmental management 47 Meteorology 46 Physical geography 41 International cooperation 36 Global environmental change 35 Environmental economics 34 Ecology 33 Environmental protection 33 Greenhouse gas mitigation 32 Renewable energy sources 30 Agriculture 29 Law and legislation 24 Greenhouse gases 21 Oceanography 21 Power resources 21 Energy policy 20 Geology 20 Regional planning 20 Water-supply 20