4.3/4.4 - Carbon Cycle and Climate change
Assessment statements
DCS Topic Code | Statement | Guidance |
4.3.U1 | Autotrophs convert carbon dioxide into carbohydrates and other carbon compounds. | |
4.3.U2 | In aquatic ecosystems carbon is present as dissolved carbon dioxide and hydrogen carbonate ions. | |
4.3.U3 | Carbon dioxide diffuses from the atmosphere or water into autotrophs. | |
4.3.U4 | Carbon dioxide is produced by respiration and diffuses out of organisms into water or the atmosphere. | |
4.3.U5 | Methane is produced from organic matter in anaerobic conditions by methanogenic archaeans and some diffuses into the atmosphere or accumulates in the ground. | |
4.3.U6 | Methane is oxidized to carbon dioxide and water in the atmosphere. | |
4.3.U7 | Peat forms when organic matter is not fully decomposed because of acidic and/or anaerobic conditions in waterlogged soils. | |
4.3.U8 | Partially decomposed organic matter from past geological eras was converted either into coal or into oil and gas that accumulate in porous rocks. | |
4.3.U9 | Carbon dioxide is produced by the combustion of biomass and fossilized organic matter. | |
4.3.U10 | Animals such as reef-building corals and mollusca have hard parts that are composed of calcium carbonate and can become fossilized in limestone. | |
4.3.A1 | Estimation of carbon fluxes due to processes in the carbon cycle. | Carbon fluxes should be measured in gigatonnes. |
4.3.A2 | Analysis of data from air monitoring stations to explain annual fluctuations. | |
4.3.S1 | Construct a diagram of the carbon cycle. |
DCS Topic Code | Statement | Guidance |
4.4.U1 | Carbon dioxide and water vapour are the most significant greenhouse gases. | |
4.4.U2 | Other gases including methane and nitrogen oxides have less impact. | The harmful consequences of ozone depletion do not need to be discussed and it should be made clear that ozone depletion is not the cause of the enhanced greenhouse effect. |
4.4.U3 | The impact of a gas depends on its ability to absorb long wave radiation as well as on its concentration in the atmosphere. | Carbon dioxide, methane and water vapour should be included in discussions. |
4.4.U4 | The warmed Earth emits longer wavelength radiation (heat). | |
4.4.U5 | Longer wave radiation is absorbed by greenhouse gases that retain the heat in the atmosphere. | |
4.4.U6 | Global temperatures and climate patterns are influenced by concentrations of greenhouse gases. | |
4.4.U7 | There is a correlation between rising atmospheric concentrations of carbon dioxide since the start of the industrial revolution 200 years ago and average global temperatures. | |
4.4.U8 | Recent increases in atmospheric carbon dioxide are largely due to increases in the combustion of fossilized organic matter. | |
4.4.A1 | Threats to coral reefs from increasing concentrations of dissolved carbon dioxide. | |
4.4.A2 | Correlations between global temperatures and carbon dioxide concentrations on Earth. | |
4.4.A3 | Evaluating claims that human activities are not causing climate change. |
Notes

4.3_4.4_notes.pdf |
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Review PowerPoint

4.3_4.4_carbon_cycle_greenhouse_effect.ppt |