Challenges for the Planet - Climate Change

Factors causing climate change
1. External
  1. Solar Output
    1. The energy coming from the sun changes over time as the sun changes over time. In the 1980s, measurements were taken that showed the amount of energy reaching the Earth had decreased by 0.1% which could, over an 100 year period, affect the global climate. It is predicted that a 1% change could make the temp. rise fall by 0.5-1°C. The Little Ice Age was thought to have been caused by a lack of sunspots.
  2. Orbital Geometry
    1. The shape of the Earth's orbit changes between a circular and elliptical shape every 95,000 years. When the orbit is more circular the Earth tends to experience glacial periods whereas more elliptical orbits have caused warm periods.
      1. The tilt of the Earth varies between 21.5° and 24.5° which occurs over 41,000 years. The greater the tilt, the warmer the summers and colder the winters are. The Earth also experiences warmer periods.
2. Internal
  1. Volcanic Activity
    1. Eruptions release large amounts of sulphur dioxide and ash into the atmosphere. These prevent the amount of solar radiation reaching the Earth's surface. In 1815 Mount Tambora erupted and the following year was unusually cold. Europe had heavy snowfall in summer and in 1816 was known as 'the year without a summer'.
  2. Tectonic Activity
    1. Movements of the continents affects the global pattern of atmospheric and ocean circulation. When the Earth changes shape, wind and ocean currents change. The process is quite slow and have a large impact on the climate over a relatively short time span of 10,000 years.
Current Climate Change
1. The Cause
  1. 1. UV radiation from the sun passes through the Earth's atmosphere.
    1. 2. The Earth absorbs EM radiation with short wavelengths e.g. UV and so warms up. Heat is then radiated from the Earth as longer wavelength IR.
      1. 3. Some of this IR is absorbed by greenhouse gases such as carbon dioxide, methane and nitrous oxide.
        4. The atmosphere warms up.
2. The enhanced greenhouse effect
  1. When the natural greenhouse effect has become stronger due to the production of more greenhouse gases.
3. Greenhouse Gases
  1. Carbon Dioxide
    1. Fossil fuels are used to produce energy in power stations and to supply fuel to vehicles.
      1. 75% of energy in China is produced from coal.
      2. Car ownership has increased dramatically since the 1960s.
  2. Methane
    1. Bacteria in swamps and marshes emit more methane as world temperature increases.
    2. The levels of methane have been rising by 1.5% a year for the past decade. Could be due to rice paddies.
    3. Western style meat based diets are becoming more popular in developing countries.
  3. Nitrous Oxide
    1. Nitrogen is removed from the atmosphere by plants (nitrogen fixation).
    2. Burning fossil fuels and wood is one source of the increase in atmospheric nitrous oxide.
    3. Microbes remove nitrogen from the soil and put it back into the atmosphere (denitrification).
4. Global Wealth
  1. As it increases, global temperature increases.
    1. The population can afford more cars.
    2. More industry.
    3. More western style diets.
Effects of Climate Change
1. Climate includes the study of temperature and rainfall.
2. Crop yields decreasing
  1. Increasing temp. and decreasing rainfall
    1. Droughts or flooding
      1. E.g. River Indus
  2. People
    1. Countries closest to the equator will suffer the most due to increased droughts.
    2. Food prices increase.
  3. Environment
    1. In Africa, countries such as Tanzania and Mozambique will have longer periods of droughts and shorter growing seasons. They could lose 1/3 of their maize crops.
    2. It is forecast that in India there will be a 50% decrease in the amount of land.
    3. Desertification occurs (when the top soil is taken off) so crops can't be grown.
3. Retreating Glaciers
  1. Decrease snowing, increase temp.
  2. People
    1. Colder temperatures in Western Europe.
  3. Environment
    1. 90% of the glaciers in the Antarctic region are retreating.
    2. Arctic ice melting could cause the Gulf Stream to be diverted further south.
      1. The loss of the ice means that polar bears of Wrangel Island, a Russian nature reserve, cannot travel overland to catch their prey.
    3. The Nef glacier in Patagonia, Chile has retreated 2 miles up its valley since the 1930s.
    4. In the 1990s, 1200 polars bears were in the Hudson Bay area of Canada, today there are 850.
    5. In Southern Greenland, the amount of ice flowing into the sea has doubled in the last 10 years.
4. Extreme Weather Conditions
  1. Oceans are the fuel for tropical storms so if they're warmer, there is more fuel.
  2. People
    1. It is predicted that there will be more storms and floods in the UK.
    2. Vanuatu - Cyclone Pam (a category 5 cyclone) - 8 people have died in the capital.
  3. Environment
    1. Since the 1970s, the intensity and duration of tropical storms have increased substantially.
    2. In Kenya, droughts happen every 3 years with the worst one they had had in 80 years being in 2006.
    3. In 2010, billions of trees in the Amazon died due to the region's worst drought on record.
    4. In August 2005, Hurricane Katrina struck Louisiana, Mississippi and Alabama. It created a storm surge that destroyed 10 miles of coastline.
5. Rising Sea Levels
  1. Ice enters the ocean or thermal expansion (warmed water particles expand).
  2. People
    1. The Hadley Centre for Climate Change at Exeter found that between 1993-2006, sea levels rose 3.3mm a year. It will lead to an 88cm rise by the end of the 21st century which is a danger for low-lying coastal land.
      1. If the sea level rises by 1m, Bangladesh will lose 17.5% of its land.
    2. Kiriabati, a group of tiny islands, had rising sea levels which rose 21.4mm per year since 2001. 2 of the islands have been completely inundated and the people have become the first environmental refugees.
    3. The islands of Tuvalu in the Pacific Ocean are expected to be completely flooded within the next 50 year. People are being evacuated to New Zealand.
  3. Environment
    1. A Greenpeace report predicts that the Great Barrier Reef in Australia will be dead within the next 30 years.
    2. Warmer sea waters make coral suffer thermal stress and bleaches them which kills them. In 2008, the UN predicted that 33% of the world's coral reefs were dead.
      1. This affects marine biodiversity and food chains.
      2. Heat makes the algae that lives with the coral polyp leave and the coral can no longer photosynthesise.

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Challenges for the Planet - Climate Change

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	Created by Olivia Graham over 10 years ago