Revision 3 The Amazon Rainforest

The dark green areas are all – what? What is the pattern of where they are? Which is B? BO? C? V? E? Key idea 1 The Amazon is in … and 4 countries that form part of it are …..

Look at the sun’s rays as they hit the Earth same width ray, more spread out – not so hot same width ray, not spread out at all, much hotter

Now lets see how the rays pass through the atmosphere Look how much thicker the air is As the rays from the sun pass through the atmosphere, some of the heat is reflected back out into space. The thicker the air, the more heat there is that never reaches earth Key Idea 2 It is hotter at the equator because the sun’s heat are more spread out/ concentrated and the sun’s rays travel through more/less atmosphere

Why does it always rain in the Amazon? About 4 o’clock nearly every day Key Idea 3 The sun heats up the warm, damp surfaces. The water turning into water vapour. Warm air rises, taking the water vapour with it. High up it is colder and the water vapour forms clouds, giving heavy rain.

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.

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 Key Idea 4 The natural greenhouse effect helps the Earth stay warm/get hotter. The carbon dioxide/oxygen in the air traps enough of the Sun’s heat to do this. The CO 2 stays the same because animals breath it in/out and plants take it in/out

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

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

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. So this is why the rainforests matter to the Earth

So these are the things that can happen if we increase the amount of greenhouses gases Some places will be wetter colder drier Windier Hotter Key Idea 5 The enhanced greenhouse effect helps the Earth stay warm/get hotter. The CO 2 stays the same/increases because we are burning fossil fuels and/or cutting down the trees

If we cut down trees the forests will suffer as well 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 The soil

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

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

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

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

Key Idea 6 Can you think of 3 ways the forest suffers when the trees are cut down? Hints Soil, temperature, vegetation, greenhouse gases, flood and drought

What are the main causes of deforestation?

So what could they do instead? We looked for sustainable activities – activities that do not use up or destroy what is there Butterfly farms – can you remember how that worked? Harvesting and growing forest fruits – acai and guarana, brazil nuts, vanilla Agroforestry – what is that? Why is it a good thing? Natura beauty products - fair trade invests in the community and saves the environment Eco-tourism that saves the things people want to see – is run by the people who live there and improved their quality of life

The last two key ideas Key Idea 7 Can you think of 3 of the main reasons why the rainforest is being cut down? Key Idea 8 Could you write a short paragraph explaining about one scheme/project that is using the rainforest in a sustainable way?