1.the whole matter is farther complicated by the overuse of ... in agriculture (chemical)

2....such as nitrogen oxide carbon monoxide and hydrocarbons have been linked to hay fever , chest infection and childhood cancer ( pollute )

3.as levels of .. carbon dioxide and methane increase , the greenhouse effect will trap increasing amounts of heat (atmosphere )

4.was the public .. of the danger of drought and crop failure ? (awareness ) 

5.they agreed to cut ... of nitrogen oxide from power stations (emit)

6. ...say that divering water from the river will lower the water table (environment )

7. there has been an ... response since the club advertised a few weeks ago (encourage)

8.they have grown awareness of commercial exploitation of forest ... (globe)