Environmental aspects -- Environmental policy -- 12 Climatic changes -- 10 Economic aspects -- 8 Congresses 7 Economic development -- 5 Environmental protection -- 5 more ... Energy policy -- 4 Government policy -- 4 Natural resources -- 4 Agriculture -- 3 Congresses -- 3 Environmental aspects 3 International trade -- 3 Petroleum industry and trade -- 3 Social aspects -- 3 Chemical warfare -- 2 City planning -- 2 Climate changes -- 2 Conservation of natural resources -- 2 Deforestation -- 2 Developing countries -- 2 Economic conditions -- 2 Economic policy -- 2 Environmental aspect -- 2 Environmental law -- 2 Foreign economic relations 2 Forest fires -- 2 Global environmental change -- 2 History 2 less ...