Climate change 26 Environmental policy & protocols 24 Politics & government 16 Applied ecology 14 Environmental economics 12 Sustainability 12 Development economics & emerging economies 10 Earth sciences, geography, environment, planning 9 Environmental science, engineering & technology 9 International relations 9 Urban & municipal planning 9 Central government policies 8 The environment 8 Economics 7 Development studies 6 Energy technology & engineering 6 Environmental management 6 Environmentalist thought & ideology 6 Political science & theory 6 Sociology 6 Conservation of the environment 5 Ecological science, the Biosphere 5 Education 5 Geography 5 Human geography 5 Meteorology & climatology 5 Physical geography & topography 5 Political economy 5 Agricultural science 4 Biology, life sciences 4