58.4 Complete the explanations. 1 We don't have to create greenhouse gases; they exist ________ naturally. 2 Greenhouse gases in the atmosphere ________ the greenhouse effect. 3 Global warming is the ________ of an increase in the amount of greenhouse gases. 4 Two ________ of climate change have been hotter summers and wetter winters. 5 A ________ is often the result of too much rain when the rivers are full. 6 A ________ is a long period without rain, and they are ________ more frequently now. 7 The ________ is the air, land and water around us. 8 If you ________ something, it is so badly damaged, it cannot be used again. 9 If something is ________, it works well and doesn't waste energy. 10 ________ is the power that comes from gas, electricity, etc.