Presentation is loading. Please wait.

Presentation is loading. Please wait.

Climate and change Year 11 revision

Similar presentations

Presentation on theme: "Climate and change Year 11 revision"— Presentation transcript:

1 Climate and change Year 11 revision

2 Key terms Key term Definition Climate Change
Long-term changes in temperature and precipitation Deforestation The chopping down and removal of trees to clear and area of forest Ecosystems A community of plants and animals that interact with each other and their physical environment Enhanced Greenhouse Effect The increased greenhouse effect resulting from human action (emission of greenhouse gases) and leading to global warming Geological Climate Events Climate changes that result from major geological events such as volcanic eruptions Global Warming A trend whereby global temperatures rise over time, linked in modern times with the human production of greenhouse gases Greenhouse gases Those gases in the atmosphere that absorb outgoing radiation, hence increasing the temperature of the atmosphere

3 Key terms Key term Definition Ice Age
A period in the earth’s past when the polar ice caps were much larger than today Little ice Age A period of slight global cooling that lasted from around the mid- 15th Century to the mid-19th Century Mega fauna ‘Big animals’ which mostly weighed over 40kg e.g. Woolly mammoth and sabre-tooth cat Natural causes Processes and forces that are not controlled by humans Orbital Changes Changes in the pathway of the Earth around the sun and the tilt on its axis Quaternary Period The most recent geological period of the Earth’s history Solar Output The energy emitted from the sun Stratosphere Layer of air 10-50km about the Earth’s surface

4 Key terms Key term Definition Food Chains
Plants and animals are linked together and dependence on each other for food Extinction Species of plant or animal dying out completely, so none survive Desertification Gradual change of the land into desert Weather short term, day to day changes in the atmosphere. Climate the average weather conditions over 30 years. Interglacials warm periods between ice ages Glacials cold periods or ice ages. Ice sheets approx m thick extended across the northern hemisphere. Air mass A huge body of air with uniform temperature and humidity.

5 Key facts: Climate graphs
You must be familiar with reading climate graphs ...practise! Read rainfall scale from here Read temperature scale from here Plymouth, UK oC mm Name months!

6 Key facts: The UK climate
UK (MEDC) Scotland Wales England

7 Key facts: The UK climate
UK (MEDC) What controls the UK climate? A lot to do with ‘air masses’. Air masses are huge blocks of air. They can be damp or dry, warm or cold, depending on where they came from and over what type of surface they have travelled. For example, an air mass that has travelled over the sea will increase its moisture content and be more likely to produce rainy weather.

8 Key facts: Past temperatures have always fluctuated
Climate has changed in the past through natural causes on timescales ranging from hundreds to millions of years.


10 Key facts: Recording past climate
How do we know climate was different in the past? Fossils of animals and plants that no longer live in the UK. Landforms left by glaciers Samples from ice sheets in Antarctica. Ice sheets are made up of layers of ice, a layer for each year. Trapped in the ice sheets are air bubbles. Climatologists study the CO2 levels to reconstruct past climates. How do we know climate has changed in the more recent past? Old photos, paintings Diaries Newspapers Recorded dates of blossom and migration of birds.

11 Natural causes of climate change
Theory Facts Eruption theory: Big volcanic eruptions can change the Earth's climate. Small eruptions have no effect, it has to be very large and explosive. Volcanic eruptions can produce ash and sulphur dioxide Gas. If the ash and gas rise high enough they will be spread about the Earth's stratosphere by high level winds. The blanket of ash and gas that this creates will stop some sunlight reaching the Earth's surface. Instead, the sunlight is reflected off this blanket back into space. This cools the planet and lowers the average temperature. Sunspot theory: Sunspots (black areas on the sun) were first recorded over 2000 years ago. Sometimes there are lots of these and at other times they disappear. Even though these spots are dark, they tell us that the Sun is more active than usual. Lots of spots mean more solar energy is being fired out from the Sun towards Earth. Cooler periods, such as the Little Ice Age, and warmer periods, such as the Medieval Warm Period, may have been caused by changes in sunspot activity. Orbit theory: Over very long timescales, there have been big changes in climate. Glacial periods were 5-6 degrees colder than today and interglacial periods were 2-3 degrees warmer than today. Such big changes need a big cause. Over long periods of time the Earth's orbit changes: The Earth's orbit is sometimes circular, and sometimes more of an ellipse (oval). The Earth's axis tilts. Sometimes it is more upright, and sometimes it is more on its side. The Earth's axis wobbles, like a spinning top about to fall over. These changes alter the amount of sunlight the Earth receives and they affect where sunlight falls on the Earth's surface. Over thousands of years these changes could start or end ice ages. These changes are called MILANKOVITCH cycles.

12 Impact of past climate change
‘Little Ice Age’ A period of significant cooling 300 years ago It had a negative impact on agriculture (farming), people & ecosystems.

13 Impact of the ‘Little Ice Age’: On people and the environment
ECONOMIC +VE ECONOMIC -VE HEALTH ENVIRONMENT FARMING English fisherman found herring normally located in the waters off Norway. Increasing grain prices and lower wine production Cool, wet summers led to outbreaks of St. Anthony's Fire illness Beech trees, were replaced first by oak and then by pine. Wheat and oats did not ripen so the harvests failed Increase in deep-sea fishing helped to build the maritime population Many farmsteads were destroyed, resulting in less tax Malaria in several parts of England Cold and rain occurred in the spring and summer of 1315 Farms high on hillsides were abandoned Cod fishing greatly decreased, as the cod moved farther south. Great Famine lasted 8 years In the Alps, valley glaciers grew in the colder climate They had to change their crops from wheat to potatoes Advancing glaciers closed the gold mines. 10-20% of farmers died from hunger

14 Impact of past climate change
.....Focus on agriculture. Western Europe experienced a general cooling of the climate between and a very cold climate between During the coldest times, England's growing season was shortened by 1-2 months compared to today. Unlike seeds today, back then the seeds could not survive the extreme cold or warmth, wetness or dryness. Price of wheat went up dramatically as it became more difficult to grow and get hold of. Climate changes had a much greater impact on agricultural output in the past. One of the worst famines in the seventeenth century occurred in France due to the failed harvest of Millions of people in France and surrounding countries were killed. In Norway, many farms located at higher latitudes were abandoned for better land in the valleys.

15 How were ecosystems affected by climate change in the past?
The dinosaur extinction was possibly caused by a massive asteroid hitting Mexico and a huge volcano in India combining:  dust, ash, gas go up into the stratosphere  which blocks the sun out  which cools the climate  so plants don’t grow  so dinosaurs have no food… …which has a knock on effect through the food chain. Megafauna extinction – big animals like the woolly mammoth and sabre-toothed tiger. The climate was warming so they had to find new areas to live where the climate suited them. This disrupted food chains. Humans also hunted them to extinction.

16 Mega fauna extinction This caused temperatures
to rise, ice to melt and glaciers to retreat. The retreating glaciers meant there was less water available for the plants & animals. The ice age (Pleistocene) period finished around 10,000 years ago. The lack of herbivores meant carnivorous animals began to die as they had less prey. The lack of plants meant herbivores (vegetarian) animals began to die. The lack of water & rise in temperature meant lots of plants died as they could not adapt. The overall change in climate caused a big change in the food chain, which meant many animals became extinct. Other theories suggest some animals became extinct because they were hunted by humans.

17 Climate change and humans
The main greenhouse gasses

18 Greenhouse gasses and temperature
“Describe the graph” 1880: Global temperature = -0.4oF Carbon Dioxide = 300ppm Fluctuating, but general increase of both global temperature and CO2 between Then a much faster rate of growth for both factors, until: 2000: Global temperature = 1oF Carbon Dioxide = 380ppm There is a direct link between the amount of carbon dioxide in the atmosphere and temperature.

19 How Does the Greenhouse Effect Work?

20 How Does the Greenhouse Effect Work?
Greenhouse gases (CO2 from the burning of fossil fuels, deforestation, Methane from paddy fields etc....) trap heat from leaving the atmosphere and re-radiate that heat back down to earth. The greater the concentration of greenhouse gases, the more heat is trapped and the warmer earth becomes. We need the NATURAL greenhouse effect – it makes the planet 16 degrees warmer. Without it the earth would be too cold for us to survive. The extra greenhouse gases produces by humans burning fossil fuels  power stations, transport, industry, homes.

21 Greenhouse gases: Change over time
Since pre-industrial times, atmospheric concentrations of greenhouse gases have grown significantly: countries become more industrialised people become consumers of energy and goods Become bigger producers of air pollution (through the burning of fossil fuels) Most greenhouse gases are produced by developed countries – the EU, USA, Japan.

22 Greenhouse gases: Change over time
The USA produce the largest amounts of CO2 each year. The world’s current level of CO2 is increasing at a rate of 200x faster than at any time in the past million years. Rates of methane have also doubled since the 1800s due to the growing world’s population demanding an increasing amount of cows for meat. Emerging powers such as China and India are now in line with older polluters such as USA and Europe due to the take off of their development. China is now the world’s largest single polluter.

23 An atlas of pollution: C02 emissions:

24 World C02 emissions: Highest C02 emissions = North America, Europe, Japan, UAE, China (predominantly MEDCs and NICs) Lowest C02 emissions = South America, Africa, Russia (predominantly LEDCs)

25 World C02 emissions: China emits more CO2 than the US and Canada put together - up by 171% since the year 2000. India is now the world's third biggest emitter of CO2 - pushing Russia into fourth place. The biggest decrease from is Ukraine - down 28% in recent years. The biggest increase is the Cook Islands - up 66.7% since 2000. But that is only one way to look at the data - and it doesn't take account how many people live in each country. If you look at per capita emissions, a different picture emerges where: Some of the world's smallest countries and islands emit the most per person - the highest being Gibraltar with 152 tonnes per person. The US is still number one in terms of per capita emissions among the big economies - with 18 tonnes emitted per person. China, by contrast, emits under six tonnes per person, India only 1.3 For comparison, the whole world emits 4.49 tonnes per person (average).

26 World C02 emissions: Reasons for variations in global emissions
MEDC LEDC Transport – more cars per capita, bigger cars, more air travel. Transport – fewer cars, less air travel, greater use of public transport. Energy supply – more electrical goods needing energy i.e. Televisions, computers, hairdryers, games consoles Energy supply – more traditional fuels used, lower demand per person, fewer electrical appliances within households. Business and industry – greater number of industries, bigger outputs, offices. Business and industry – more primary and secondary industries. Homes – larger homes, central heading/air conditioning, more energy intensive construction. Homes – smaller homes, often traditional building methods with less environmental impact.

27 Effects of the environment
Effects on people Effects of the environment

28 Predicting the future:
Why is it hard to predict future levels of greenhouse gases? We don’t know if people will change their lifestyles and recycle more, or use more public transport. We don’t know if we will continue to use fossil fuels, or change to cleaner energy like wind or solar We don’t know what the world’s future population will be

29 Climate change will have positive & negative impacts on people, the environment and countries economies. Case studies! Developing countries will be affected more negatively than developed countries.

30 How might a developed country be affected by climate change?
UK More extreme weather Sea level rise Warmer UK (MEDC)

31 How might a developed country be affected by climate change?
UK (MEDC) Warmer Sea- level rise More extreme weather

32 Future UK climate UK (MEDC)
Overall UK summers and winters will be warmer. Temperature on average will rise by 4°C by 2080. In the summer heat waves will be become more common as temperatures reach 40°C Rainfall in the summer is expected to decrease and as a result we will suffer from more droughts. Winters will bring less snow and more rain. We will also receive more severe storms.

33 How might a developing country be affected by climate change?
Egypt (LEDC) A developing country Low greenhouse gas emissions – 2.6 tonnes per person per year (world average = 6.8) Produce less than 1% all green house gases. 99% of Egypt’s people live in 5% land area as so much is desert. Average rainfall = less than 10mm/yr The River Nile is an important water supply.

34 How might a developing country be affected by climate change?
Egypt (LEDC) With Global Warming… If sea levels rise 50cm, 1/3 of the city of Alexandria would be under water. 10% Nile Delta would flood  7 million people would have to leave their homes  farming would be hit  there would be less food  famine. Less and more unreliable rainfall  water shortages. Desertification Heat waves  illness and death. Malaria increase. Water Wars? 86% of the Nile’s water starts it’s journey in Ethiopia. Uganda, Sudan and Ethiopia are all building huge dams for Hydro Electric Power (HEP). This could have a serious impact on the amount of water reaching Egypt  This could lead to conflict and war. Egypt has a debt of $30 billion. It may not be able to cope with the impacts of global warming.

35 Extras!

36 Video revision: What are air masses?
Antarctic Ice reveals Climate History Dinosaurs Extinction Evidence for global warming - polar ice caps Climate change dangers Global Warming - None Like It Hot! BBC climate experiment Climate Change and the future of weather Egypt struggles with climate change

37 Past GCSE questions: A Outline one reason why sea level is expected to rise in the future (2 marks) Describe two impact of melting ice sheets on the environment (2 marks) Describe one impact of a short term past climate change on a) People b) the environment (4 marks) Explain how natural events can cause climate change. (4 marks) Describe two natural cause of climate change. (4 marks) Explain how human activity is leading to climate change. (4 marks)

38 Past GCSE questions: B Describe how two human activities can contribute to climate change. (2 marks) Give two reasons why developing countries often produce less carbon dioxide than developed countries (2 marks) Explain the possible economic (money) impacts of climate change on a named country. (4 marks) Describe one way in which climate change might make people poorer (2 marks) For a named developing country, explain why climate change is likely to have a large impact on its people. (6 marks)

39 Past GCSE questions: C For a named developing country, explain how climate change is likely to have a large impact on its economy. (6 marks) For a named country, suggest one possible impact of higher global temperatures. (2 marks) State two possible impacts of climate change in the UK (2 marks) Explain how the future climate of the UK is likely to be affected by global climate change (6 marks) Describe how climate change in the past, such as the Little Ice Age, affected people and ecosystems. (4marks). Describe how colder periods, such as the Little Ice Age, affected farming. (2 marks)

40 Good luck!

Download ppt "Climate and change Year 11 revision"

Similar presentations

Ads by Google