STARTER - All these picture represent the possible effects of increased mean global temperature– what can you see? Can you think of any other effects? Good or bad?

Global warming Learning outcomes All of you will be able to: Identify potential effects of increased mean global temperature. Most of you should be able to: Describe these possible effects and identify that they may be good or bad. Describe feedback mechanisms associated with an increase in mean global temperature. Some of you might be able to: Discuss the potential effects of increased mean global temperature and the associated feedback mechanisms.

Describe what is happening in this map of the US? Explain why this has happened? Predict what you expect to see if there is an increase in the mean global temperature?

Crop-growing areas Warmer temperatures should increase the rate of biochemical reactions so photosynthesis should increase. Drought reduces crop yield and reduction in water sources will make it difficult to irrigate crops. Changes in locations of crop growing areas with movement north and south from the equator. A 30% drop in crop yield across Africa and the Middle East is expected if temperatures rise by 3°C.

Weather patterns More heat means more energy in the climate and so weather will be more violent and sporadic with bigger storms and droughts. Global precipitation may increase up to 15% – However there could be reduced rainfall over USA, Southern Europe and the Commonwealth of Independent States.

Coastal inundation Sea levels are rising. As water heats up it expands Melting of ice in Antartica and greenland cause sea levels to rise as it flows into the oceans °C increase could lead to a sea level rise of 15-95cm. (IPCC) This will affect low-lying nations like Bangladesh and the Netherlands.

Effect on societies Insect disease vectors will spread to more regions. Algal blooms may become more common and some are toxic In a wetter climate fungal disease will increase. In a drier climate asthma and chest infections increase. Some economies would suffer if water supplies decrease or drought occurs. 4 billion people could suffer from water shortage if the temperature increases by 2°C. Others would gain if it becomes easier to exploit mineral reserves.

Feedback mechanisms What does positive and negative feedback mean? Take a look at the table with both possible negative and positive feedback mechanisms that may arise from global warming. Choose 3 of the feedback mechanisms (at least one negative and one positive) and draw a diagram to represent what is happening in each one.

Student take over… One person is going to come up and summarise what we have seen today. Someone else will come up and question the class on what we have seen today. You now have 5 minutes to prepare your summary and the questions you would ask to the class.

Homework Research and write a paragraph for each point: What are the different pollution management strategies that have been introduced to address the issue of global warming? – Think about: global and local reactive and preventive – How effective have they been? What are the different arguments surrounding global warming? – Explain the conflicting arguments surrounding global warming. – Identify the complexity of the problem and the level of uncertainty of global climate models. – What is global dimming?