Presentation on theme: "Global Climate Change Learning Objectives:"— Presentation transcript:
1 Global Climate Change Learning Objectives: To understand the evidence for and against global climate change- World and UK temperatures for the last 100 and 1000 yearsTo know the causes of global warmingTo know the consequences of global climate change- social, economic, environmental and political consequences of global climate change and how they change the way we live.
2 Figure 8, is a newspaper extract describing floods in Sheffield in June 2007. 1) Give two pieces of evidence that suggest Sheffield experienced extreme weather conditions before the flood (2 marks).2) Describe the different ways in which people’s lives were affected by the extreme weather in Sheffield in June 2007.
3 1)- Wettest June in 120 years of records being kept (1)This was 44mm higher than the second highest year in 1982 (1)50mm of rain fell in just 1 day (1)2)Businesses were destroyed so people would lose their jobsWorkers were trapped in factoriesFamilies were airlifted from their flooded flatsShops and restaurants were destroyedRailways were disrupted so people could not get home or to workGoods were unable to be moved around the area so businesses would suffer.
4 The Causes of Climate Change Climate change: the Earth’s climate has always changed naturally over time. One reason for this is thought to be that the Earth’s orbit varies around the sun, which has led to ice ages and warmer periods..Evidence for climate change – BBC class clip
5 Global warming: an increase in world temperatures as a result of the increase in greenhouse gases (carbon dioxide, methane, CFCs and nitrous oxide) in the atmosphere brought about by:the burning of fossil fuels e.g. coal, oil and natural gas for industry and transport, and to heat our homesClearing rainforests (which act as ‘carbon sinks’ to naturally absorb excess carbon dioxide from the atmosphereFarming (particularly cattle farming, which generates methane)Some people, particularly in the media, have linked these recent extreme weather events (particularly the European heatwave of 2003) to global warming. Although extreme weather events may become more frequent as the atmosphere warms up, no individual can be blamed on global warming. Evidence would have to be drawn from a much longer period of time- hundreds of years- before any reliable links can be made
6 Greenhouse effect- a completely natural process where gases in the atmosphere trap the heat from the sun. The gases act like the glass in a greenhouse- they let heat in but prevent some of it from getting back out.Greenhouse gases are essential to keep the Earth warm. Without them, most of the planet would be a frozen wasteland.
7 As the greenhouse gases in the atmosphere increase, we are getting an enhanced greenhouse effect (the greenhouse effect is working more strongly). This is leading to an increase in average temperatures around the world- global warming. As a result more people believe that the climate is changing because of human activities.
8 The average global temperature has increased steeply in the last 10 years, but if you look over a longer time period, you can see that the average global temperature has risen and fallen. For instance, the rate of increase in temperature between 1910 and 1920 was about the same as the rate of increase between 2000 and today, but there were steep drops in average global temperature in the years and However, the overall trend has generally been upwards since but at different rates- so the picture is not a straightforward one.Natural processes- show global temperature change from 900 to about 1900 (including a warm period and mini ice age). These are know as climate change sceptics.
10 Coastal flooding from rising sea levels More frequent and severe droughtsWider spread of insects pests e.g. malarial mosquitoesSea warming reduces supplies of planktonSnow and ice melt in the mountains
14 Outline one possible cause of global climate change (2 marks) 2) Study Figure 6 on the insert, which shows the predicted global, Northern hemisphere and Southern hemisphere temperature change from 2000 to Describe the trends shown by the graph (4 marks)
15 The world increases by 0. 2 degrees by 2010 and has gone down to 0 The world increases by 0.2 degrees by 2010 and has gone down to 0.1 degrees by It then goes up to 0.6 degrees by 2030.Increases are greater in the Northern hemisphere after 2030, when temperatures everywhere have increased by 1degreesThe trends fluctuate with rises and falls occurring every so many years e.g. the start of decades 2040 and 2050 and 2070.Increases in the two hemispheres diverge and there is a predicted difference of 1.5 degrees by 2100.