An introduction to climate change. Contents. Section 1: What is climate change? Recent climate history and future projections Section 2: The greenhouse effect Section 3: Human activities causing climate change Section 4: Why does climate change matter? What can be done about it?
Contents Section 1: What is climate change? Recent climate history and future projections Section 2: The greenhouse effect Section 3: Human activities causing climate change Section 4: Why does climate change matter? What can be done about it? Section 5: What can governments do? Section 6: What can you and your family do? Section 7: Summary
Section 1: What is climate change? Recent climate history and future projections
What is climate? • The long-term average of a region’s weather: • Average rainfall. • Average hours of sunshine. • Average temperature. • Climate versus weather: • Weather describes whatever is happening outdoors in a given place at a given time. • Climate describes the total of all weather occurring over a period of years in a given place. • Climate tells us what it's usually like in the place where you live at a certain time of year.
Climate change • Climate change represents a change in these long-term weather patterns. • Average temperatures can increase or decrease. • Rainfall can increase or decrease, as can hours of sunshine. • Climate change has occurred naturally over millions and millions of years. • However when scientists talk about the issue of climate change, their concern is about global warming caused by human activities.
The Earth is warming • The earth has warmed by over 0.5°C in the last 100 years. • The eleven years 1995-2006 rank amongst the twelve warmest years since records of global surface temperature began in 1850.
Melting glaciers, rising sea levels • A warmer earth is causing glaciers and ice sheets to melt. It is also leading to rising sea levels. • The summer ice in the arctic is predicted to disappear completely between 2013 and 2040; a state not seen on earth for more than a million years. • The next slide shows the Triftgletscher glacier in Switzerland, comparing 1948 with 2002 and 2006.
Predicting the future • In general scientists agree that temperature rises of 2°C above pre-industrial levels are almost inevitable, and rises of 3°C are likely. • This may not sound like much but even a small increase in temperature over a long time can change the climate.
Predicting the future – average temperature increases predicted by 2100
Understanding climate change To understand human-induced climate change it is helpful to look first at the ‘greenhouse effect’.
The greenhouse effect • Greenhouses work by trapping heat from the sun. • The glass panels of the greenhouse let in light but keep heat from escaping. • This causes the greenhouse to heat up, much like the inside of a car parked in sunlight, and keeps the plants warm enough to live in the winter.
The greenhouse effect • The earth’s atmosphere (the air that we breathe) contains a number of so called greenhouse gases. • The ones most closely associated with global warming are carbon dioxide (CO2) and methane (CH4). • These gases behave like the glass panes in a greenhouse.
The greenhouse effect • Incoming shortwave radiation from the sun • Sunlight (short wave solar radiation) enters the earth’s atmosphere. • Most of this solar radiation is absorbed by the earth’s surface (land and sea) and warms it. • Some of it is reflected by the earth back into the atmosphere. • Outgoing longwave (infrared) radiation from the earth • In return the earth admits long wave energy back into the atmosphere. • Because it is longwave energy (not shortwave like the energy carried by the rays from the sun), some of it gets trapped by the greenhouse gases. • This causes the earth to be warmer than it would without the greenhouse gases. • The thicker the blanket of greenhouse gases, the more the outgoing energy gets trapped and the greater the warming effect.
Summary • Human activity is causing a thick blanket of greenhouse gases to build up in the atmosphere. • These gases are trapping heat and causing the earth to warm.
Burning fossil fuels • Since the Industrial Revolution the need for energy to run machines has steadily increased. • Much of this comes from fuels like coal and oil – fossil fuels. • Burning these fuels releases greenhouse gases. • Note that coal and oil are the main fuels used by power plants producing electricity. So most things that run on electricity indirectly cause greenhouse gas emissions.
All of these activities contribute to global warming: • Driving a car • Flying by plane • Travelling by bus or train • Electric lights • Watching TV • Using the computer • Washing and drying clothes • Cooking a meal • Heating your home
Deforestation • Mature forests store enormous quantities of carbon, which is released into the atmosphere when they are cut down. • Forest covers 30% of the world’s land area. We are destroying 28,000 square miles a year.
The human cost of climate change Climate change threatens the necessities of life that we take for granted – access to food and water and political stability: • By 2080 half the world’s population could face a shortage of water because of climate change. • By 2050 200 million people could be permanently displaced by floods, rising sea levels and draughts. • Food and water shortages could lead to migration and instability on a scale not seen before.
Species endangered by climate change • Changes in climatic conditions can harm the delicate ecosystems in which species live. • The speed at which change is happening means that many plants and animals may not be able to react quickly enough to survive.
Cutting emissions from energy generation • The government can drive efforts to switch to renewable energy and reduce carbon emissions in energy generation: • Solar power • Wind power • Nuclear power • Bio-energy • Carbon capture and storage (for example burying carbon dioxide emissions underground).
Cutting deforestation • Most deforestation occurs in developing regions: • Brazil / South America • Indonesia / Asia • Africa • These countries need financial support to replace loss of earnings from logging.
Putting a price on carbon • The true ‘environmental’ cost of carbon needs to be reflected in the cost of fuel, electricity and food. • Taxes and regulation will ensure that the polluter pays. • So if the ‘price of carbon’ is set at £50 per tonne, and a flight to Australia and back emits 10 tonnes of carbon per passenger, the price of the flight will rise by £500.
Emissions trading • The poorest developing countries will be hit earliest and hardest by climate change, even though they have contributed little to causing the problem. Their low incomes make it difficult to finance adaptation. • Kyoto's clean development mechanism caps emissions by rich countries, forcing them to buy permits from poor countries to emit greenhouse gases. • The funds raised are then invested in projects that reduceemissions in the developing countries. • The emissions trading program of the European Union is the hub of the global market; the value of EU carbon emissions trading reached $50bn in 2007.
Activities increasing the level of greenhouse gases Transport: • Riding in a car • Getting on a bus or train • Flying Home energy use (unless powered by renewable energy): • Turning on the lights • Watching TV • Using the computer • Washing and drying clothes • Cooking a meal • Heating your water • Heating your home
Food for thought • In the UK emissions from homes are responsible for an estimated 27% of the UK’s total carbon emissions. You and your family’s behaviour and choice and use of technologies are major determinants of your energy use. • A report by the Energy Saving Trust predicts that by 2010 the UK could waste up to £11 billion annually and emit around 43 million tonnes of carbon dioxide through wasted energy, such as leaving lights on and appliances on standby. • More than 30% of the trips made by cars in Europe are for less than 2 miles and 50% for less than 3 miles. Walking or cycling will cut emissions and improve air quality, reduce congestion and improve road safety.
All of this will help: • Ride a bike or walk instead of going by car. • Turn the lights off when you leave the room. • Cut your TV watching. Don’t leave the TV on standby – turn it off at the wall. • Recycle as much as possible . Recycle cans, bottles, plastic bags, and newspapers. When you recycle, you send less rubbish to the landfill and you help save natural resources, like trees, oil, and elements such as aluminium. • Don’t waste food. • Eat less beef and dairy products. Cows produce methane which is one of the most damaging greenhouse gases. • Plant trees. Planting trees is fun and a great way to reduce greenhouse gases. Trees absorb carbon dioxide from the air. • Buy recycled products which don’t use ‘new’ resources and don’t require so much energy to make. Buy energy efficient electrical goods.
Ask your parents to: • Try not to fly (the emissions from flights are really high). Take the train instead: a short haul flight emits six times as much carbon per passenger as a high speed train, and 12 times as much as a coach. • Use public transport where possible, or share a car to work / school. • Make their car as energy efficient as possible. Choose a smaller engine: small is beautiful. A 2.0 litre engine emits 40% more CO2 per mile than a car with an engine size 1.4 – 2.0 litres. • They could also switch their vehicle to LPG (autogas) - it’s 40% cheaper and greener. As well as cutting CO2 emissions by 20%, they will also cut production of harmful gases such as carbon monoxide and nitrous oxide by more than half.
Ask your parents to: • Use low energy light bulbs. • Turn the thermostat down. • Make sure their loft and hot water tank are properly insulated to stop heat from being lost unnecessarily. • Switch to ‘green energy’. Companies like ‘Good energy’ offer energy produced by solar power and wind turbines. • Install their own solar panels or wind turbine.
Summary • Average temperatures around the world are increasing. • Whenever we burn fossil fuels or cut down trees we release greenhouse gases into the atmosphere, primarily carbon dioxide and methane. • These gases trap heat in the atmosphere and warm up the earth. The more we burn fossil fuels and cut down trees, the more the earth’s surface heats up. • The average temperature is expected to rise by at least 2°C by the end of this century, probably more.
Summary • Whilst this doesn’t sound like much, it is enough to ensure billions of people could suffer from water shortages and heatwaves. In addition melting ice sheets and rising sea levels could cause flooding and the displacement of millions of people. • 30% of animal species are thought to be at risk of extinction. • We all need to tackle climate change – by cutting our use of energy and switching to renewable sources of energy (energy produced by the sun, wind, hydro-electricity and nuclear).