Prior learning –There are 3 kinds of rock – sedimentary, metamorphic and Igneous –Igneous rocks form crystals depending on the length of time it takes them to cool down -Theory of continental drift -Rock cycle Key words –Photosynthesis, respiration, decomposition, decomposers, decay, carbon, cycle, fossil fuels, combustion, greenhouse effect, climate change, Unit 11 – Science and Humanity October Title: Task 5: Changes that occur during the carbon cycle and the effects on climate change.

IAM LEARNING: Describe the long-term changes that have occurred in our universe to our solar system and earth I WILL BE SUCCESSFUL IS I CAN: Identify the changes of the carbon cycle Understand what the combustion of fossil fuels are Explain the greenhouse effect Explain the theory behind climate change I CAN: Complete the stages in the carbon cycle Explain how the combustion of fossil fuels impacts on the carbon cycle and how this in turn impacts on the greenhouse effect Explain the link between climate change and fuel consumption and identify any governmental measures that are or are planned to be put in place to reduce the effects Unit 11 – Science and Humanity

I’m a viscous semi-solid with convection currents circulating in me. I’m iron and nickel too, but I’m liquid. I just hang around on the outside. I’m really very thin and am mostly silicon, oxygen and aluminium. I am dense, very hot, made mostly of solid iron and nickel. Inner core Outer core Atmosphere Crust Mantle STARTER: What am I? Unit 11 – Science and Humanity

The Earth was formed about 4,500 million years ago. During the first billion years there was intense volcanic activity, which produced the early atmosphere. This would have contained large quantities of carbon dioxide (CO 2 ) and water vapour. Methane (CH 4 ) and ammonia (NH 3 ) are thought to have also been present. This is rather like the atmosphere on Mars and Venus today. The water vapour condensed to form the oceans. Mars Venus The early atmosphere Unit 11 – Science and Humanity

Carbon dioxide reacted with rocks and much became trapped in them. The evolution of algae some 3,000 million years ago, and subsequently plants which successfully colonized the Earth’s surface, led us towards the present atmosphere. Their photosynthesis replaced carbon dioxide with oxygen. Over a period of time, billions of tonnes of carbon dioxide became locked up in fossil fuels. Earth Photosynthesis increased oxygen levels Oxygen levels increase Unit 11 – Science and Humanity

As oxygen levels rose, atmospheric ammonia (NH 3 ) reacted with oxygen(O 2 ) to form water (H 2 O) and nitrogen (N 2 ). Also, living organisms, including denitrifying bacteria, broke down nitrogen compounds releasing more nitrogen into the atmosphere. And so the atmosphere headed towards a composition that has remained fairly constant for the last 200 million years. Nitrogen appears 78% 21% 1% Nitrogen Oxygen Other Unit 11 – Science and Humanity

Copy the timeline and arrange the blue boxes in appropriate places along the line. 4,500 million Now 3,000 million 2,000 million 1,000 million 500 million 200 million No gases H 2 and He CO 2 NH 3 CH 4 H 2 O N 2 O 2 Volcanoes Algae Plants Atmosphere timeline Unit 11 – Science and Humanity

All positions are approximate 4,500 million Now 3,000 million 2,000 million 1,000 million 500 million 200 million No gases H 2 and He Volcanoes Algae Plants CO 2 NH 3 CH 4 O 2 N 2 H 2 O Atmosphere Timeline Unit 11 – Science and Humanity

Use the graph to estimate the answers. 1.How long ago was the atmosphere 75% CO 2 ? 2.How long ago were the CO 2 and N 2 levels in the atmosphere equal? 3.How long ago was the atmosphere 50% nitrogen? carbon dioxide nitrogen oxygen 100% 50% 0% 5,0003,000 0 Composition percentage Time (millions of years) now Approx 4,000M Approx 3,300M Approx 2,000M PLENARY: Changing gas levels Unit 11 – Science and Humanity

IAM LEARNING: Describe the long-term changes that have occurred in our universe to our solar system and earth I WILL BE SUCCESSFUL IS I CAN: Identify the changes of the carbon cycle Understand what the combustion of fossil fuels are Explain the greenhouse effect Explain the theory behind climate change I CAN: Complete the stages in the carbon cycle Explain how the combustion of fossil fuels impacts on the carbon cycle and how this in turn impacts on the greenhouse effect Explain the link between climate change and fuel consumption and identify any governmental measures that are or are planned to be put in place to reduce the effects Unit 11 – Science and Humanity

Oxygen normally exists as pairs of atoms (O 2). Oxygen can, however, turn into another form that has three atoms joined together. This is ozone (O 3 ). As oxygen levels rose, so did the amount of ozone. This layer of ozone in the atmosphere filters out harmful ultraviolet rays from the sun. This will have allowed new organisms to evolve and survive. 3O 2  2O 3 oxygenozone Earth Harmful UV rays stopped with ozone layer Harmful UV rays reach Earth’s surface without ozone layer Ozone: a vital filter Unit 11 – Science and Humanity

The carbon cycle

CO 2 release or consumption? Unit 11 – Science and Humanity

Over millions of years the carbon cycle has maintained a constant, low percentage (approx. 0.03%) of carbon dioxide in the atmosphere. In 1860, the CO 2 level was about 289 ppm (parts per million). Here is a table showing the CO 2 levels over a recent 10-year period. What percentage change is this and does it matter? Carbon dioxide and temperature Unit 11 – Science and Humanity

From air trapped in Antarctic ice, we have a good idea of CO 2 concentrations going back 160,000 years. Which label goes with each picture? 200ppm CO 2 300ppm CO 2 We also know the temperatures over the same period. The very warm interglacial period of 130,000 years ago was accompanied by CO 2 levels of around 300 ppm. The previous great Ice Age had CO 2 levels around 200 ppm. Changing CO 2 concentrations Unit 11 – Science and Humanity

Normally the Earth absorbs heat and emits heat at the same rate. Because of this the temperature remains constant. Certain gases, like CO 2 and methane, act like a greenhouse. They let heat in but do not let it out. This is called the greenhouse effect. This means that the more CO 2 there is, the hotter planet Earth is! Earth Heat from sun Heat loss More CO 2 Earth Heat from sun Heat loss hotter And hotter And hotter! balanced same temp The greenhouse effect Unit 11 – Science and Humanity

Work through Task 5: Effect on Climate Change using the information you have gathered in the past lessons Unit 11 – Science and Humanity