Geography revision weather and climate


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Geography revision weather and climate

  1. 1. Geography Revision Unit 1 – Weather and Climate The Climate within the UK There are FIVE main reasons for the changing/fluctuating temperature in the UK. You will need to memorise each of them by heart! Depressions Okay, the depressing part of the GCSE is the “depressions”. 1) They form in the Atlantic Ocean, then move east over the UK. 2) The warm air is less dense so it rises above the cold air 3) Condensation occurs as the warm air rises causing rain clouds to develop 4) Rising air also causes low pressure at the Earth’s surface 5) So winds blow into the depression in a spiral (High to low pressure) 6) A warm front is the front edge of the moving warm air. 7) A cold front is the front edge of the moving cold air. Latitude (how far north or south of the equator something is, the further north you go, the colder it is)  The sun is at a lower angle in the sky so its heat energy is spread over more of the earth’s surface. Prevailing Wind  The UK’s most common prevailing wind is from the south west.  It brings moist, warm air, making the UK wet and warm.  The West gets more heat and rain than the east. Distance from the sea  Areas nearer the sea are warmer in winter because the sea shores keep them warm.  Areas near the sea are cooler in summer because the sea takes a long time to heat up.  The West gets more warmed up than the East due to the North Atlantic Pressure Systems (from the west)  Low pressure from the west makes a lot of rainfall as the air is rising and the water vapour is condensing.  The is opposite for high pressure Altitude (how high the land is)  The higher the altitude, the colder the temperature as the air is thinner.  The higher the altitude, the wetter it is as the vapour condenses.
  2. 2. People’s homes and lives  Floods damaged homes and prized possessions  Businesses were flooded  Contaminated water supplies  In drought, a lack of water supplies. E.g. the “hose pipe ban” Health  Flood can cause deaths by drowning  Heat waves can cause death by heat exhaustion  Milder winters may reduce cold-related deaths Transport  Floods can block roads and railways, disrupting transport systems  High temperatures can cause railway lines to buckle so trains can’t run properly  People will become anti-social and isolated due to a lack of transport Agriculture  Droughts will cause crop failures  Increased rainfall could be good and increase production  A warmer climate means farmers can grow a wider variety of crops Anticyclones These are almost the opposite of a depression. They cause clear skies and dry weather. 1) These also form in the Atlantic Ocean and move east over the UK. 2) These create high pressure as the warm air is falling 3) This warm air can hold more water so there is NO RAIN. 4) Creates clear skies in summer, however, it’s very different in winter 5) In winter, anticyclones give long periods of cold, foggy weather. Heat is lost from the earth’s surface at night because there are no clouds to reflect it back. The temperature drops and condensation occurs near the surface. Extreme UK weather The weather in the UK is getting more extreme. In other words, there is more rain; more floods and temperatures are increasing. The impacts of this changing climate are as follows: Reducing Negative Impacts 1) Preparing – flood defences and better education of the issue 2) Planning – emergency services should know all the procedures 3) Warning – warning systems give people time to prepare for extreme weather
  3. 3. Threat of Global Climate Change Climate change is any change in the weather of an area over a long period. Global warming is the increase in global temperature over the last century. 1) Global temperature has been measured using thermometers for the last 150 years. During the last 100 years, average global temperature has risen by about 0.9*c. 2) Scientists have also reconstructed the climate over the last 1000 years using things like historical records, tree rings and cores taken from ice sheets. 3) This shows that global temperature is rising sharply now compared to how it was in the past 4) There’s some other evidence too:  Ice sheets are melting  Sea level is rising Causes 1) An increase in human activities like burning fossil fuels and deforestation has caused an increase in the concentration of carbon dioxide and methane 2) These are greenhouse gases – they trap heat reflected off the Earth’s surface 3) Greenhouse gages keep the Earth warm because they trap heat. Increasing the concentration of greenhouse gasses in the atmosphere means the Earth heats up too much – causing global warming. Impacts Economic Impacts – Climate change will affect farming in different ways round the world. In higher latitudes, warmer weather will mean some farmers can make more money – some crop yields will be increase, and they’ll be able to grow new types of crops to sell. Social Impacts – People won’t be able to grow as much food in lower latitudes. This could lead to malnutrition, ill health and death from starvation. Environmental Impacts – Global warming is causing sea level to rise, so some habitats will be lost as low-lying coastal environments are submerged. Rising temperature and decreased rainfall will mean some environments will turn into deserts. Political Impacts – Water will become scarcer in some places. Competition over water could lead to war between countries. Climate change may cause people to move, therefore increased immigration. Reponses International – Kyoto Protocol, their aim is to reduce global greenhouse gas emissions by 5% below 1990 levels by 2012. Each country is set a target and there are meetings to make sure countries are keeping to their target. America is not included in this. National - Transport strategies can be improved upon, making sure less people use the car. Taxation on high polluting vehicles and factories could also reduce emissions. Local – Conserving energy, recycling and congestion charging will all reduce emissions.
  4. 4. Tropical Storms Tropical storms create quite a lot of havoc. This is where the hurricanes come in. Most people will be doing hurricane Katrina as an MEDC and Burma as an LEDC. Tropical storms are called a variety of things such as hurricanes or typhoons, but they are all basically the same thing. This is how they are formed: 1) Only formed when sea water is 27*c or higher. 2) Happen in late summer or autumn 3) Warm moist air rises and condenses 4) They move west because of the easterly winds near the equator 5) They lose strength when they move over land because the energy supply from the water is cut off 6) Most tropical storms happen between 5* and 30* degrees north and south of the equator, any further north and the water isn’t hot enough 7) The Earth’s rotation deflects the path of the winds which causes the storms to spin Characteristics  Anti-clockwise spin and move north west.  They’re circular in shape and usually last between 7 and 14 days  The lose their strength when they move over land  They are extremely powerful due to their consistent spirally of hot air The Eye  Low pressure  High temperature  No clouds  No rain The Eye wall  Low temperature  Spiralling rising air  Strong winds  Torrential rain The Edge  Low pressure  High temperature  No clouds  No rain