1 The Amazon What do we need to know to understand why the Amazon is important?

2 There some really good questions Such as If the trees in the rain forest were all cut down how would it effect the earth? What would happen if the weather pattern in the Amazon changes? How would the world change if all of the Amazon was cut down? But to help us think about these, what do we need to think about first? There is a question that we would have to think about before we could go on to look as these others – any ideas?

3 I think we will have got there?? What is climate change and what has it to do with global warming?

4 Phrases we hear include … The Greenhouse Effect Global Warming Climate Change Before we look at these, there are 2 sources of the Greenhouse Effect the Natural Greenhouse Effect the Enhanced Greenhouse Effect the first being useful, the second, well who knows?

5 The Natural Greenhouse Effect Without it, Earth would have no living things and would be more like Venus or Mars This is because the temperature would be on average 30 0 C colder than it is This is how it works…

6 The Natural Greenhouse Effect at work The Earth is covered by a blanket of gas. The energy from the Sun reaches the Earth’s surface, where some it is converted to heat energy. Most of the heat( blue arrows) is re-radiated towards space, but some is trapped by the greenhouse gases in the atmosphere. This natural effect allows the Earth’s temperature to be kept at a level necessary to support life.

7 The Natural Greenhouse Effect at work The main Greenhouse Gas is Carbon Dioxide. Until the last 200 years, the amount of CO 2 has remained stable. This is why Can you explain what is happening here?

8 But then there is the Enhanced Greenhouse Effect Look how this is different! Much more of the heat from the sun gets trapped in the atmosphere So the Earth gets hotter

9 Why is more heat getting trapped? We are taking the stored carbon from the ground (oil and coal and gas) and burning it This releases the CO 2 and so the main greenhouse gas is increasing

10 Where does the rain forest come into this? The only way carbon dioxide can be taken out of the atmosphere is by the plants – and trees are better at it than most because they are bigger and need to make more sugar to grow. Without our forests, less of the carbon dioxide would taken out of the air, so more of it would be left to trap more heat from the sun.

11 If there are more greenhouse gases in the air What kind of things can we expect to happen? (it is not just a mater of everywhere getting hotter)

12 I think we may have covered most of these Some places will be wetter colder drier Windier Hotter

13 But are the effect on the rain forest of the trees being cut down?

14 The soil Before: moist, shaded, with lots of leaves to make compost After: dry and desiccated as the sun dries up the soil and makes it cracked – the compost blows away

15 The temperature Before: the temperature is kept down in the day because of the shade, but the trees act as a blanket making it only a bit cooler at night After: Very hot in the day but cools quickly at night with no protective trees

16 Vegetation Before: Lots of thing grew After: With poor soil and the water evaporated, it would turn into a desert eventually

17 Greenhouses gases Before: As much as 10% may be trapped After: None is taken in. But worse still even more can be released, by burning or rotting

18 Flooding and drought Before: Heavy rain hits the tree-tops and drips down through the branches, runs down the trunks and soaks into the soft earth After: The heavy rain hits the baked earth hard, forming puddles and floods. The earth has been baked by the sun so it floods and then runs off into the river, taking any loose soil with it – this is called soil erosion

19 And then there is the human and environmental problems Amerindians are loosing their homelands The plants and animals are lost forever Rainforests contain medicines - an estimated one in four of all purchases from pharmacies in countries such as Britain contain an active ingredient derived from a tropical forest species. And only 1 % of the plants have yet been tested

20 Homework HotPotatoes