- Slides: 25
Climate change • Climate change is a natural phenomenon • In the past the world climate has fluctuated over millions of years. • We have had warmer periods called inter-glacial (like the current warm period we are in) • And cool periods called glacial (known as ice ages) • These changes are thought to be due to changes in the output of solar radiation
Global warming • Global warming is the recent warming that is occurring in our atmosphere as a result of human activities. • Global warming is a result of the ‘enhanced greenhouse effect. ’
The Greenhouse Effect 1. The sun releases radiation (short wave) that travels across space to earth 2. Some of the suns radiation enters the earths atmosphere some is reflected by the atmosphere back into space. 1 4 2 5 3 3. As the earth is warmed up by the solar radiation from the sun, it also released radiation (infrared radiation – long wave) 4. Some of the infrared radiation escapes the earths atmosphere back into space 5. The rest of the infrared radiation is trapped by greenhouse gases in the atmosphere, this causes earth to warm.
The Greenhouse Effect • The greenhouse effect is natural and keeps our planet warm. • without it life would not have formed on earth. • However humans are enhancing the greenhouse effect by adding greenhouse gases to the atmosphere which cause the earth to warm even more!! • This is called the Enhanced Greenhouse Effect
The Greenhouse Effect Click on the link to watch the video on You. Tube. It is a short clip from the ‘Inconvenient Truth’ explaining the greenhouse effect Click on the link to watch the video on the ‘Greenhouse effect’
Greenhouse Gases Water Vapour Carbon Dioxide Burning fossil fuels (coal, oil and gas) Deforestation and burning of trees. Occurs naturally and not influence by human activities Greenhouse gases Methane Gas pipeline leaks, farming rice in paddy fields, cattle farming. Halocarbons Does not occur naturally. It is the most powerful green house gas. Produced in Industry Nitrous Oxide Jet aircraft engines, cars and lorries, fertilisers and sewage farms.
Human activities • Cars and transportation – increased car ownership and increases in air travel all contribute. Both burn fuel that releases co 2 into the atmosphere. • Deforestation – trees take in co 2 and store it. When trees are cut down/burnt co 2 is released back into the atmosphere. • Electricity – 76% of our electricity comes from burning fossil fuels which release co 2 into the atmosphere • Technology – Increases in technology often require more electricity. E. g. mobile phones, computers etc. • Increased population – mean more electricity is used, more cars are driven and more tress are cut down.
Evidence for global warming • Average world temperatures have risen by 0. 6 degrees Celsius Graph showing global average changes.
Evidence for global warming • Evidence of glaciers and ice sheets melting (e. g. Rhone glacier in Switzerland has retreated by 2. 5 km over the last 150 years) The Rhone Glacier – the white lines show that the glacier used to be further down the valley
Evidence for global warming • Ice cores from the Antarctic ice sheet show that amounts of carbon dioxide and methane in the atmosphere have increased as a result of human activity. Ice cores Graphs – CO 2 levels
Evidence for global warming • Increases in extreme weather events such as tropical storms and drought. Some of the biggest hurricanes have occurred in the past 10 years • Birds, insects and fish species that are found in Africa are spreading north
Impacts of Global Warming • There are both positive and negative impacts of global warming. Click on the link to watch the video by National Geographic on ‘Global Warming’ Click on the link to watch the video by National Geographic on ‘ 6 degrees could change the World’
Positive Impacts Agriculture • New agricultural regions will be created in areas such as northern Canada • UK will have a longer growing season and may be able to grow crop like oranges that currently grow in southern parts of Europe. Tourism • As temperatures increase tourist hotspots will move north in Europe. E. g. beaches in Scandinavia could become the new Costa del sol. • Warmer temperatures could also increase tourism to British beach resorts E. g. Brighton.
Negative Impacts Sea Level Rise • 3. 8 billion people (60% of worlds population ) live 60 km away from the coast. This is likely to rise to 75% by 2030 • Between 1900 and 2000 world sea levels rose by 2 mm per year • This would impact upon people living on the coast e. g. Holderness, UK. • If all ice was to melt sea levels would rise by 65 m – whole countries would disappear (e. g. Maldives, Bangladesh) and cities (e. g. Venice, Miami, New York, London) Agriculture • Main agricultural regions will shift north. With some areas turning into deserts. One area to be affected is south east of USA (cereal grains) • Reduction of crops produced in sub-Saharan Africa is likely to result in severe famine.
Negative Impacts Extreme weather events • Tropical storms (hurricane) will become more common and those that do occur will be stronger. • Increased number of storms will also affect the UK. The Thames barrier has had to be used more in recent years to protect against storm surges which cause flooding. (1983 only closed once, 2007 closed 11 times) • Heat waves like the one that hit Europe in 2003, where 35, 000 people died, will be far more common. • Countries in sub-Saharan Africa are more likely to suffer from drought. Diseases • Tropical diseases such as Malaria could spread further. Many diseases are only found in areas where there are tropical climates, if temperature rises there could be more areas that will have tropical climates.
Negative Impacts Fauna and Flora • Many plants and animals will go extinct as the climate changes and they are unable to adapt to the new climatic conditions. • Polar bear numbers have already been affected. Many polar bears hunt on the sea ice in the Arctic Ocean. As this sea ice is melting earlier every year, the time they have to hunt is also decreasing. Tourism • Ski resorts such as those in the Alps will disappear. Having a major impact on the economy of these areas. • As temperatures increase tourist hotspots like the Costa del Sol may lose tourist as they decide to holiday further north.
Reducing Global Warming • To reduce global warming we need to reduce the amount of greenhouses gases (e. g. CO 2) that are being released into the atmosphere. • The next few slides give different ways we can do this.
Reducing Global Warming Deforestation/ Afforestation • Trees play an important role in regulating the gases in our atmosphere. • The breath in carbon dioxide and breath out oxygen. • Therefore it is important that we protect the remaining forests we have. • Afforestation is occurring in many areas where forest have been lost and can help reduce the amount of CO 2 in the atmosphere.
Reducing Global Warming Renewable Energy • Renewable energy sources e. g. solar energy, wind energy • We need to create electricity using renewable energy sources that do not release greenhouse gases into our atmosphere. • Currently only 15% of our electricity comes from renewable sources.
Reducing Global Warming Energy Conservation and efficiency • We need to change our lifestyles so that we reduce our carbon emissions. • For example people can reduce their energy consumption by insulating their homes, using energy low appliances, using public transport more and taking fewer flights.
Reducing Global Warming Carbon Capture and storage • Carbon dioxide can be captured from fossil fuel power stations. • it is possible then to convert this gas into a liquid where it can be stored under ground in the rocks. • This would reduce the carbon dioxide going into our atmosphere. • However this would be expensive to setup.
Reducing Global Warming Bio fuels • There a number of crops that produce oil that can be processed to make fuel for cars and aircraft. • These biofuels could reduce poverty in developing countries by creating jobs and wealth for farmers. • Also people in developing countries could use their cars and take flights without worrying about carbon emissions and fossil fuels running out.
Reducing Global Warming Governments have been working together to reduce global warming. One way they have done this is by the creation of the Kyoto protocol
Reducing the Impact of Global Warming • Defend low lying coastal areas from flooding • Improve water supplies in areas that suffer from drought (e. g. putting wells with hand pumps into villages) • Encourage research into crops that can withstand drought and disease. • Develop more efficient way to predict and prepare for extreme weather events such as tropical storms.