Derek McMonagle
Reviewers: Marlene Grey-Tomlinson, Bernadette Ranglin, Maxine McFarlane & Monacia Williams
We are learning how to:
• explain climate change in terms of human activity
• consider the possible effects of global warming.
The average surface temperature of the Earth has increased by about 0.8 °C over the last 100 years. Much of this increase has occurred in the last 30 years. This suggests that the trend in rising temperature is increasing.
This may not sound like much of an increase, but even this small rise has caused major changes to the climate in different parts of the world. This is known as global warming
The average winter temperature at the North Pole is around −34 °C while in the summer the average is around 0 °C. Scientists who study the North Pole have been aware for some time that average temperatures are increasing. The northern polar ice cap is slowly getting smaller and the ice is getting thinner as more ice turns to water
In some parts of the world the summers are getting much hotter and drier. Warmer weather has led to water shortages and droughts in certain parts of the world.
Water is being used up more quickly than it can be replaced by nature.
In areas of the world where there are large forests, the vegetation is much drier than in the past due to higher temperatures and lack of rain.
You should work in a small group for this activity. Here is what you should do:
1. Discuss what effects a drought is likely to have on people and on wildlife.
2. Imagine there is a drought in your area now. Discuss what steps you could take to reduce the use of water
1. Copy and complete the following sentences by writing either ‘increasing’ or ‘decreasing’.
a) The surface temperature of the Earth has been over the last 100 years.
b) The thickness of the ice at the North Pole is
c) In some parts of the world summers are getting hotter and drier. The effects of this are that:
i) water levels in lakes and reservoirs are .
ii) the risk of forest fires is .
iii) the number of wild animals and farm animals dying from lack of food and water is .
There is land beneath the ice at the South Pole, but the North Pole consists entirely of ice. If the northern polar ice cap were to completely melt it would be possible to sail over the North Pole.
global warming rise in average surface temperature of the Earth
droughts lack of rain
We are learning how to:
• explain climate change in terms of human activity
• explain the greenhouse effect.
Greenhouse gases are gases that can absorb and emit heat radiation. The main greenhouse gases in the atmosphere, as far as global warming is concerned, are water vapour, carbon dioxide, methane and ozone.
Many scientists believe that global warming is caused by increasing concentrations of greenhouse gases in the atmosphere. This increase is the result of human activities.
The increase in concentrations of greenhouse gases in the atmosphere is commonly called the greenhouse effect because these gases have a similar effect to the glass roof and sides of a greenhouse. Heat becomes trapped in the greenhouse causing the temperature to rise.
heat radiation from layer of greenhouse gases re-radiated in all directions
heat radiation from surface of Earth back out into the atmosphere
heat radiation is absorbed by the layer of greenhouse gases in the atmosphere
heat from the Sun
The greenhouse effect should more correctly be called the enhanced greenhouse effect. The greenhouse effect has existed as long as the Earth has had an atmosphere. Without the greenhouse effect, Earth would never have become warm enough to support life as we know it.
We are learning how to:
• explain climate change in terms of human activity
• consider the impact of climate change.
Climate and weather are different things and should not be confused. The weather is about what is happening now at a particular place. We might describe the weather in Kingston today as wet or dry, warm or cold, windy or calm.
The climate is concerned with weather conditions over a long period of time in a large area. It is more general and gives a more overall picture. When we say that the climate in Jamaica is generally warm and sunny this doesn’t refer to a particular day but to most days.
Although we might say that the climate in an area is warm and dry in the summer and cold and wet in the winter this doesn’t mean that every summer day is equally warm and dry and every winter day is equally cold and wet.
You might have heard people say things like ‘last summer was hotter than usual’ or ‘there wasn’t much rain last winter’. Within any area there are natural fluctuations in the climate. When global warming and climate change was first suggested not all scientists were convinced that the greenhouse effect was to blame. They argued that what countries were experiencing was simply natural variation. The situation has now become clearer and most scientists accept that global warming is responsible for unseasonal weather conditions that have affected large areas of the world over the past decade.
In 2012, a study of the climate in Jamaica found that the frequency of warm days, warm nights and extreme high temperatures had increased while there were fewer cool days, cool nights and extreme low temperatures. In other parts of the world, the climate change has been far more dramatic. Here is an example.
Glaciers are found near the tops of high mountains or at the Earth’s poles where it is very cold. They are sometimes described as rivers of ice. Snow accumulates over time, continually forming huge sheets of ice that flow very slowly down the mountain. The top of the glacier is continually replenished while the bottom will eventually melt as it warms up.
Global warming has accelerated the rate with which glaciers are melting all around the world. At first glance this might seems a good thing since it releases lots of fresh water into the environment. However, this also causes problems.
• Valleys into which glaciers flow have now become lakes and local environments have been lost.
• Where the water flows out to sea, the salinity decreases, which affects marine organisms.
• The level of the sea is rising, which affects low-lying countries like the Maldives in the Indian Ocean.
Activity 8.5.1
How might climate change in Jamaica affect my life? Your teacher will organise the class into small groups for this activity.
Within your group discuss how you think your life might be affected if there are long-term climate changes in the Caribbean. You might consider:
Advantages like: more sunlight = more electricity from solar power plants
Disadvantages like: less rain = more expensive vegetables and fruits
Check your understanding
1. The following pictures show the Muir Glacier in Alaska, USA in two different years.
On the planet Venus, the greenhouse effect traps so much heat energy that the average surface temperature is 462 °C.
a) How many years passed between the two pictures?
b) What is the main change that can be seen in the pictures?
c) Suggest a reason for this change.
climate conditions like average temperature, average rainfall over an area over a long period of time
weather local conditions on a day like temperature, amount of rainfall, wind direction glacier extremely large mass of ice which moves very slowly, often down a mountain valley
We are learning how to:
• describe ways of reducing greenhouse gases
• describe other initiatives to mitigate climate change.
Since there are clear links between greenhouse gases, global warming and climate change, any initiative to reduce climate change must involve a reduction in the levels of greenhouse gases. The contribution of an individual gas depends on its greenhouse index value and its concentration in the upper atmosphere.
Although the greenhouse index of carbon dioxide is small, it is present in a relatively high concentration in the upper atmosphere. The gradual increase in atmospheric carbon dioxide over the past century has been closely associated with global warming, so we will focus on initiatives for reducing the concentration of this gas.
A carbon dioxide sink is a carbon reservoir that increases in size. The main natural sinks are:
• plants and other organisms
• the oceans into which carbon dioxide dissolves
Any initiatives involving reforestation in the Caribbean, will increase the capacity of natural sinks.
shale
sand
carbon
native
carbon-bearing
There are now plans to remove carbon dioxide from the atmosphere and store it in traps under suitable layers of rock.
The biggest single source of atmospheric carbon dioxide is the combustion of carbon-based fuels such as coal, natural gas and those made from crude oil, such as diesel and petrol. Any initiative to reduce the numbers of vehicles powered by diesel and petrol engines will be hugely beneficial.
Scientists and technologists have experimented with electrically powered cars for many years. They don’t burn a fuel and therefore don’t produce carbon dioxide.
Recent developments in battery technology mean that electric cars are now possible and the numbers in use will rapidly increase over the next decade. Scientists are also working on electrically powered trucks.
Fossil fuels are also burnt on a large scale in power stations to generate electricity. The Taichung Power Plant in Taiwan is the world’s biggest coal-fired power station, and also the world’s biggest producer of carbon dioxide. It releases 40 million tonnes of carbon dioxide into the air every year.
Any initiative that promotes the use of alternative energy sources will reduce atmospheric carbon dioxide.
You will not need any equipment or materials for this activity You should work in groups of 3 or 4.
1. Carry out some research to find the meaning of the term ‘carbon footprint’.
2. Make a list of the ways in which you, and your family, contribute to your own personal carbon footprint.
3. Discuss in your group how, as an individual, you can reduce your carbon footprint.
1. Read the following extract from an article in the Jamaica Observer and answer the questions beneath.
Around the world, support is growing for electric cars.
Automakers are delivering more electric models with longer range and lower prices, such as the Chevrolet Bolt and the Tesla Model 3. China has set aggressive targets for electric vehicle sales to
curb pollution; some European countries aim to be all-electric by 2040 or sooner
Those lofty ambitions face numerous challenges, including one practical consideration for consumers: If they buy electric cars, where will they charge them?
a) What models of electric cars are mentioned?
b) Which countries will actively promote the use of electric cars in the future?
c) What problem is foreseen in persuading people to move to electric cars?
Biofuels, like biodiesel, are sometimes described as ‘carbon neutral’ because the amount of carbon dioxide released when they are burnt is equal to the amount of carbon dioxide absorbed by the plants when they are growing.
Key terms
carbon dioxide
sink removal of carbon dioxide gas from the atmosphere
reforestation planting
trees to create new areas of forest
battery device for storing electricity
We are only aware of the changes that have taken place to the Earth’s climate because of the scientists who, over the years, have collected data and kept accurate records.
For example, the Mauna Loa Observatory on Hawaii has been gathering data about the composition of the atmosphere since 1956. It is thanks to their records that we can see how the concentration of atmospheric carbon dioxide has risen over the past half century
Some schools are already involved in gathering data about weather which may one day help scientists to gain a better understanding about climatic change. Your Principal has decided that she would like your school to contribute and she has invited you to come up with a plan.
1. You are going to work in groups of 3 or 4 to investigate how your school can best obtain data about weather and keep records. The tasks are:
• To review what sort of data would be most useful.
• To determine what data you will collect.
• To design, obtain or make instruments that will allow you to gather this data.
• To determine suitable locations for setting up your instruments in order to collect data.
• To test out your instruments at these locations.
• To modify your instruments and review whether the locations chosen are suitable.
• To devise methods of recording data in such a way that it will be most useful.
• To give a presentation in which you explain what you have done and to provide recommendations which are supported by the results of your work.
a) Look back through the unit and identify data used to describe weather and climate. For example, mean temperature and mean rainfall are important. Are you able to measure other features, such as the concentration of particles in the air that might affect air quality? Are there any organisations that you could contact for advice, such as the Meteorological Service of Jamaica?
b) What devices can you make to gather data about the weather? You might have a look on the Internet for making simple rain gauges and wind vanes. Recording the maximum and minimum temperature requires continuous monitoring. Can devices that do this be bought cheaply? Take some pictures while making your instruments.
c) Where can the measuring devices be set up? They need to be somewhere safe where they experience the weather but at the same time they need to be protected from extreme weather conditions, like very strong winds. Also, you don’t want people or animals tampering with them. Take some pictures of likely locations.
d) How are you going to trial your devices and your location? How long should the trial last? How are you going to decide if the trial is a success or a failure? Your data needs to be accurate. Is there another source of data with which you can compare? For example, does the local newspaper publish information about the weather? Is any information available on the Internet? How will you decide if the location is good? For example, you might consider how easy it was to access your equipment and take measurements. Take some pictures or a video of your equipment in operation.
e) What modifications might you need to make to your equipment? You might want to make it more robust, easier to read, more accurate, simpler to use. Are there other locations you might like to try that you think will be more accessible or perhaps give more accurate data?
f) How will you record your data? A pen and a book are nice and simple but this may not be the best solution. How about using a spreadsheet? The data can be stored electronically and you will be able to carry out mathematical processes like finding means or plotting graphs more easily.
g) Prepare a presentation in which you inform people about what you set out to do and how you accomplished it. Use photographs and video to illustrate your talk and show your audience some of the devices you used. Don’t be reluctant to talk about things that went wrong. Failure often provides the scientist with as much useful guidance as success.
Demonstrate how you store your data and explain the advantages of it.
