Carbon Footprint toolkit Contents

Transcription

1 arbon Footprint toolkit ontents lick on a title to jump to one of these factsheets. The Earth s natural systems Factsheet 1: What is a climate? Factsheet 2: The carbon cycle Humankind and energy Factsheet 3: arbon and energy Factsheet 4: The greenhouse effect and climate change Factsheet 5: arbon emissions and carbon footprints The impact of energy use Factsheet 6: The effects of climate change Factsheet 7: Global carbon agreements Factsheet 8: Reducing emissions who can play a part? Energy for the future Factsheet 9: Energy for the future Factsheet 10: Solar and wind power Factsheet 11: Wave and tidal power Factsheet 12: iomass and biofuels Factsheet 13: Nuclear and hydrogen power Factsheet 14: Hydro and geothermal power Factsheet 15: arbon capture and storage OTPRNT TOOLK T

2 Factsheet 1: What is a climate? t is extremely cold near the North and South Poles, but it can be baking hot around the equator. This enormous difference creates air and ocean currents that flow around the Earth. These currents cause the different weather patterns we see around the world. A region s climate is the average of its weather patterns over a long time. A climate depends on: the region s distance from the equator its height above sea level whether it is near to an ocean the air or ocean currents that affect it local features, like mountain ranges or lakes. limates are classified into zones, such as mountain, arid, Mediterranean or tropical. Each zone is home to different living things. These groups of plants and animals, together with the climate they inhabit, are called biomes. Global temperatures are rising, which can cause dry, cracking earth The Earth s overall climate has changed slowly over time. This change in climate is a natural process Plant and animal species in each biome had time to adapt Humankind is altering this process. The Earth s climate is now changing faster than before. This will affect climate zones and biomes all over the world. Many living things in each biome may struggle to adapt and survive. As global temperatures rise, the breeding grounds for many species are already moving north and south away from the Equator towards the Poles. This may mean that the boundaries between some biomes are changing. 2 The carbon cycle 4 The greenhouse effect and climate change 6 The effects of climate change OTPRNT TOOLK T

3 Factsheet 2: The carbon cycle Almost all of the Earth s carbon is locked away as sedimentary rocks. ut carbon is also in us, and all around us. t is stored in: living things (plants and animals) the atmosphere lakes and oceans. Many natural processes use this carbon. Plants take carbon dioxide from the atmosphere Some animals eat plants Others eat these animals All animals return carbon dioxide to the atmosphere as they respire The size of each store, or carbon sink, has changed slowly over time. Millions of years ago the atmosphere was rich in carbon. As life evolved, tiny plants removed much of this carbon from the atmosphere. This change was very slow. The size of each carbon store has also changed slowly. ut our energy use has introduced a new process into the carbon cycle. Sedimentary rocks also contain fossil fuels. These are the oil, coal and gas that formed from the remains of plants and animals that lived millions of years ago. When we burn fossil fuels for energy, the carbon that they store is released into the atmosphere as carbon dioxide. This process has altered the balance of the carbon cycle, and the atmosphere now stores more carbon than before. Each process takes carbon from one store, and adds it to another. This carbon cycle moves carbon between the different stores in our environment. The carbon cycle You are about 18% carbon. This has come from the plants and animals that you eat. Originally, every carbon atom came from the atmosphere. At some point, each one will return there. OTPRNT TOOLK T 1 What is a climate? 3 arbon and energy 4 The greenhouse effect and climate change 5 arbon emissions and carbon footprints

4 Factsheet 3: arbon and energy Around 150 million years ago, simple marine plants thrived in warm seas. They trapped large amounts of energy in their cells. Over time, geological processes turned their remains into oil and gas. oal formed over 300 million years ago from the remains of plants that lived in forest swamps. These also locked up carbon from the atmosphere. When they died, they were buried deeply and over time were converted into coal. These fossil fuels changed the carbon cycle as they formed. The process trapped vast amounts of carbon This removed it from the atmosphere The atmosphere became a smaller carbon store Today, coal, oil and gas are humankind s most important energy sources. All over the world, their energy is released by combustion. This takes place in power stations, transport, homes and industry. A power station, which releases the energy of fossil fuels The Earth s overall climate has changed slowly over time. ombustion uses the carbon trapped in fossil fuels t releases carbon dioxide back into the atmosphere The atmosphere is becoming a larger carbon store Since 1959, the amount of carbon dioxide in the atmosphere has increased by 21%. This is faster than any natural change. This rapid increase is why the Earth s climate is changing. Oil, gas and coal are still slowly forming in some parts of the world. ut it will be millions of years before they will be in a form that could be used. 1 What is a climate? 2 The carbon cycle 4 The greenhouse effect and climate change 5 arbon emissions and carbon footprints OTPRNT TOOLK T

5 Factsheet 4: The greenhouse effect and climate change The sun bathes the Earth in solar radiation. Most of this passes through the Earth s atmosphere. t is absorbed by the Earth s surface, which warms up. Some energy is radiated back as infrared (heat) radiation. nfrared radiation has a longer wavelength than sunlight. Gases in the upper atmosphere now absorb some of this energy. t is radiated back towards Earth. This warms the Earth s land, oceans and atmosphere. t is called the greenhouse effect. The gases that trap this heat energy are known as greenhouse gases. They include carbon dioxide (O 2 ), water vapour, and methane (H 4 ). The greenhouse effect is a natural process. t has kept the Earth much warmer than it would otherwise be. This has allowed life to flourish. The greenhouse effect explains why humankind s activities contribute to climate change. urning fossil fuels for energy adds more carbon dioxide to the atmosphere Farming adds methane, from farm animals and flooded rice fields uried waste, like paper or food scraps, also produces methane These extra greenhouse gases in the atmosphere trap more heat energy This extra heat energy changes the world s climate Earth s climate has always changed slowly over time. ut this modern rise in temperatures is called global warming. Go to launch the climate change activities and click on Greenhouse Effect to find out more and test your knowledge. A diagram to explain the greenhouse effect Without the natural greenhouse effect, the average temperature on Earth would be around -18. That s the temperature in a freezer. 2 The carbon cycle 3 arbon and energy 5 arbon emissions and carbon footprints 6 The effects of climate change OTPRNT TOOLK T

6 Factsheet 5: arbon emissions and carbon footprints Energy from fossil fuels is essential for modern life. These fuels release carbon dioxide into the atmosphere when they are burned. Each person makes choices about: what they do and buy how and where they travel the amount of energy they use what they do with their waste. These choices determine how much carbon dioxide and other greenhouse gases, such as methane, are emitted because of the person s actions. This is the person s carbon footprint. t is measured in tonnes of carbon dioxide. arbon footprints can be worked out for: groups of people, like a family activities, like a car journey, or putting the kettle on products, from clothes to new buildings places, like a school or office different periods of time, like a month or year. A carbon footprint shows how much a person, place or product may affect the Earth s climate. The more energy you use, the more carbon you emit A larger carbon footprint means a greater contribution to climate change arbon footprints all add up. The whole human race has a carbon footprint. This represents our total effect on the Earth s climate. The construction of our carbon footprint Even recycling helps. The more paper and card you keep out of landfill, the less methane you ll be responsible for emitting. 3 arbon and energy 4 The greenhouse effect and climate change 6 The effects of climate change 7 Global carbon agreements 8 Reducing emissions who can play a part? arbon footprints can help to show where each person or place could reduce their climate impact. Find out more using the nteractive school carbon calculator. OTPRNT TOOLK T

7 Factsheet 6: The effects of climate change The P is a group of scientists that monitors climate change predictions. They suggest that by the end of the century, global average temperatures could rise by between 1.8 and 4.0. This will cause glaciers and ice sheets to melt, which will cause sea levels to rise. Scientists don t know exactly how much warming will occur, but every continent may be affected. Flooding: an effect of climate change Africa Asia Australia and New Zealand Europe Latin America North America Polar regions Small islands rops could be reduced by 50%. etween 75 and 250 million people will find it harder to find water. oastal areas will face increased flooding from seas and rivers. Flooding will cause more disease and deaths. Sites like the Great arrier Reef may lose many species. Many areas will lack water, leading to lower crop yields. There may be more flash floods, and more frequent coastal flooding. Heat waves and wildfires may increase. Some tropical forests may change to savannah, losing many species. Lower agricultural output may create more hunger. Western mountains will lose snow and ice, leading to more winter flooding. More heat waves will pose health risks. Glaciers, ice sheets and sea ice will reduce, causing more of the Sun s energy to be absorbed instead of reflected. Sea level rise may increase flooding, storms and erosion, threatening species and communities. SOURE: P limate hange 2007 Synthesis Report, Summary for Policymakers, tables SPM1 p8, SPM2 p11 12 Your life could be affected by changes in weather, sea levels or agriculture. ut you can take action today to help reduce the impact of some of these changes. OTPRNT TOOLK T 4 The greenhouse effect and climate change 7 Global carbon agreements 8 Reducing emissions who can play a part?

8 Factsheet 7: Global carbon agreements Most nations have signed agreements to deal with increasing carbon emissions. These are needed because each country s emissions enter the atmosphere, where they affect every country on Earth. Global agreements can work. hemicals known as Fs damage the protective ozone layer in the atmosphere. An international ban phased out their production in 1996, and the damage to the ozone layer is reducing. The 1997 Kyoto Protocol (which has been signed by more than 180 countries) is a global agreement to tackle greenhouse gas emissions. As part of this agreement, nearly 40 countries have accepted an emissions target. Developed countries are expected to do more to cut their emissions than developing countries, because developed countries have produced more emissions in the past. ut many developing countries need to use much more energy in future because their populations and economies are growing. This is one of the reasons why some developed nations did not sign the Kyoto Protocol. They believed that developing countries like hina and ndia should also do more, as they produce large amounts of emissions. Key World Map: Kyoto Protocol, participation Signed and ratified Signed, ratified pending Signed, ratified declined No position A map to show the countries that have agreed to the aims of the Kyoto Protocol A modern, high standard of living depends on energy use, which can cause emissions. The challenge is to balance the right to a good standard of living, with the responsibility to limit the world s emissions. OTPRNT TOOLK T 4 The greenhouse effect and climate change 8 Reducing emissions who can play a part? 15 arbon capture and storage

9 Factsheet 8: Reducing emissions who can play a part? Governments that have signed the Kyoto Protocol should create national plans to meet their target. These governments can encourage people to make choices that reduce their emissions. ut each nation will only reach its targets if everyone plays their part. Your school is a good example: The media can show people how to make better choices encourage everyone to take responsibility. The government can set targets for each school to reduce its emissions provide help and advice. YOU can share a car, walk, or take the school bus switch the lights off when you leave the classroom use a plug to save hot water put paper and packaging in the recycling bin. The school staff can choose to invest in energysaving equipment develop travel plans that reduce emissions set a good example to students. To reduce carbon emissions, switch the lights off when you leave the classroom usinesses can develop new energy technologies provide help and advice. Your actions will affect your school, your life, and the lives of people in other nations. Your actions today will help to create the future for us all. Take action today! Use the interactive calculator animations and tips, form an energy-saving team and help everyone to reduce your school s emissions. OTPRNT TOOLK T 5 arbon emissions and carbon footprints 6 The effects of climate change 7 Global carbon agreements

10 Factsheet 9: Energy for the future Fossil fuels provide most of the world s energy. We depend upon them, and many developing countries want to use more. They took millions of years to form. ut humankind will have taken just a few hundred years to use them up. This means that fossil fuels are non-renewable energy sources. Oil and gas could be in short supply within your lifetime. Fossil fuels also cause carbon emissions and so contribute to climate change. ut we can t simply stop using them. So we need to use what remains more efficiently, so that: they contribute less to climate change they last as long as possible. Renewable energy sources like wind contribute less to climate change and don't run out We also need new sources of energy that can one day replace fossil fuels. Renewable energy sources are replenished as fast as they are used up. They never run out, and can lead to much lower emissions. They include wind, solar, wave and tidal power. Nuclear power is not a renewable energy source, but it could replace or supplement fossil fuels. Renewable energy sources, along with nuclear power and technologies that can reduce greenhouse gas emissions when fossil fuels are burned are together known as alternative energy. These sources of energy could: help to avoid a future dominated by climate change provide secure energy supplies when fossil fuels run out. You can already use renewable energy today, for electricity in your home, and to power things like MP3 players. OTPRNT TOOLK T 3 arbon and energy 4 The greenhouse effect and climate change 5 arbon emissions and carbon footprints Alternative energy factsheets

11 Factsheet 10: Solar and wind power Solar power The Sun is a star. t is over 150 million kilometres away, but you can easily see and feel its energy. Solar power uses this energy to generate electricity or to provide direct heat. Photovoltaic (PV) systems convert the Sun s light energy into electricity. PV systems can be expensive Large-scale PV may not be the best choice for countries with a lot of cloudy weather t may become very important in regions that receive a lot of sunlight Solar water heating traps the Sun s heat energy in a series of pipes. The sun heats up water in the pipes The heat can be used in homes and other buildings This works even in cooler, cloudy countries Solar panels at P Wolf Point Solar plant in Durango, olorado Wind power Winds form when the Sun heats some parts of the atmosphere more than others. Where the wind blows strongly, it has a lot of kinetic energy. Wind turbines capture kinetic energy from the wind The blades turn, and gears multiply this turning motion A generator converts the kinetic energy into electrical energy Wind power can also do mechanical work, to grind wheat into flour or to pump water from deep underground. Wind power could be an important energy source. ut wind turbines work best where there are no obstructions, and larger turbines are more efficient than small ones. Wind farms are built where turbines can make the most of the wind s energy Alternative energy factsheets OTPRNT TOOLK T

12 Factsheet 11: Wave and tidal power Wave power Winds form when the Sun heats some parts of the atmosphere more than others. Waves form when these winds blow across the sea. So the energy in waves starts with the Sun. Some wave energy devices can be attached to the seabed or coast. Waves push air in and out of the device This air turns the blades of a turbine A generator turns this kinetic energy into electrical energy Floating devices can be moored offshore. As waves pass over them, the device bends. This bending motion drives a generator. Hydroelectric power: one way to offset carbon emissions Wave power could be an important energy source for countries with long coastlines. ut it is still being developed and tested. Tidal power As the Moon orbits the Earth, its gravitational pull makes the sea level rise and fall. This movement creates tidal currents. Tides contain kinetic energy. Underwater turbines turn this into electrical energy. The turbines are usually placed inside a barrage, a type of dam built across a tidal inlet or bay. New designs, more like wind turbines, can stand on the seabed. Tidal power could be an important energy source for countries with long coastlines. ut tidal power is still being developed. arrages that block the tide may harm the marine environment. These effects must be understood before large tidal power schemes are built Alternative energy factsheets OTPRNT TOOLK T

13 Factsheet 12: iomass and biofuels Plants use photosynthesis to store energy from the Sun in their leaves and stems. Living things, like these plant materials, are known as biomass. carbon dioxide + water > glucose + oxygen light energy iomass captures carbon dioxide from the atmosphere. When biomass is burned, the carbon dioxide is released again. This might be in a wood stove, or a large power station. So it seems as though burning biomass would not affect the total amount of carbon dioxide in the atmosphere. n practice, energy from other sources sometimes large amounts is used to grow and process the biofuel crops. A leaf from a photosynthesising plant iofuels are made from biomass. Most cars on the road at the moment cannot use pure biofuels nstead, current biofuels are blended with conventional petrol or diesel n the future, it will be possible for more advanced biofuels to be blended at higher concentrations. This will mean that less fossil fuel is required in the blends, and may result in greenhouse gas emissions that are lower than the emissions of existing biofuels. Not all biofuels are equal in terms of climate change; biomass and biofuels will help reduce carbon dioxide emissions only if they are carefully managed. Scientists are investigating new biofuel crops. These are not food crops and can be grown on land that is not needed for food Alternative energy factsheets OTPRNT TOOLK T

14 Factsheet 13: Nuclear and hydrogen power Nuclear power n a nuclear reactor, atoms of Uranium-235 are split in a process called nuclear fission. Nuclear fusion releases energy, which heats up the reactor The heat is used to turn water into steam The steam drives a turbine and generator The generator converts the energy from nuclear fission into electrical energy Uranium is a non-renewable resource. ut there is enough uranium for nuclear power to provide energy for a long time to come. Nuclear power does not burn its fuel, so it emits very little carbon dioxide. ut nuclear power does produce dangerous radioactive waste. This remains toxic for thousands of years. A hydrogen tap at a fuel station Some people worry about the risks posed by nuclear power and its waste. ut many governments want to build more nuclear power stations, because they offer a lower-emissions source of energy. t could be an important energy source for the future. Hydrogen power Fuel cells react hydrogen with oxygen from the atmosphere to produce heat and electricity. Fuels cells do not burn the hydrogen They do not produce greenhouse gas emissions Hydrogen fuel cells can be made almost any size, for mobile phones, cars or even a power station. ut there are still problems to solve. Hydrogen is difficult to store and handle. t is made by breaking down water, or by decarbonising fossil fuels. oth these processes use energy This energy use can emit carbon dioxide t should be possible to make hydrogen from water using renewable energy. This hydrogen would store the renewable energy so it can be used when needed. This would contribute very little to climate change. OTPRNT TOOLK T Alternative energy factsheets

15 Factsheet 14: Hydro and geothermal power Hydro (hydroelectric) power Hydroelectric power uses a large dam to trap rainwater. This floods a valley to form a reservoir. The reservoir acts as an energy store. The water is released to move a turbine and generator. This converts the kinetic energy of the moving water into electrical energy. Hydroelectric power provides renewable energy. t is already used around the world. ut flooding a valley can have a big impact. Farmland will be lost, and wildlife disrupted ommunities may be forced to move The vegetation in the valley decays underwater, which releases greenhouse gases uilding the dam uses a lot of energy and materials, which also contributes to emissions A geothermal plant in alifornia giving off steam With careful planning, hydroelectric power can still be a good choice to reduce emissions in the long run. Geothermal power The Earth is hot inside. Most of this heat comes from radioactive decay. This heats up the surrounding rocks. This heat can be used as an energy source. Water is pumped down into the hot rocks. f the rocks are hot enough, the water turns to steam, which drives a generator to produce electricity f the rocks are not so hot, or the pipes not so deep, the returning hot water can be used directly, to heat homes and businesses Drilling deep enough can be very expensive. Geothermal power is only economic where the right rock conditions exist underground Alternative energy factsheets OTPRNT TOOLK T

16 Factsheet 15: arbon capture and storage Fossil fuels will remain an important energy source until they finally run out. The challenge is to make the most of what is left, while reducing emissions to combat climate change. A diagram to show types of carbon capture and storage arbon capture and storage (S) is not a source of energy. t is a new technology that can reduce greenhouse gas emissions when fossil fuels are burned. S traps the carbon dioxide that power stations produce, or the carbon can be removed from the fuel before the power stations burn it. This is decarbonisation. One method is to split fossil fuels into their constituents. These are a mixture of two gases hydrogen and carbon dioxide The hydrogen is burned to provide energy that is almost carbon-free The carbon dioxide is compressed, and piped into underground storage Key 1 O2 pumped into disused coal fields displaces methane, which can be used as fuel. 2 O2 can be pumped into and stored safely in saline aquifers. 3 O2 pumped into oil fields helps maintain pressure, making extraction easier. arbon capture and storage The carbon dioxide can be stored in the same reservoirs from where oil and gas were extracted. The O 2 can even help to force more oil and gas from these fields. These geological formations should secure the carbon dioxide forever, in practical terms. S prevents this carbon from entering the atmosphere and contributing to global warming. 2 The carbon cycle 3 arbon and energy Alternative energy factsheets OTPRNT TOOLK T