Impacts of climate change

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  • Created by: keeels
  • Created on: 09-05-14 12:21
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  • Impacts of climate change
    • Ice is melting
      • The melting of ice on land (e.g the Greenland and Antarctic ice sheets) means that water stored as ice returns to the oceans
      • This increases the volume of water in the oceans and causes the SEA LEVEL to RISE. This kind of sea level change (caused by an increase in water volume) is called EUSTATIC sea level change
      • If all the remaining ice sheets melted it would cause global sea level to rise by between 60 and 80 metres
      • Increase global temperatures also means that the oceans get warmer and expand. This thermal expansion also increases the volume of the water, causing sea level to rise further
      • This could raise sea levels by between 8 and 80cm for each increase in global temperatures of 1 degrees
        • Predictions of how much the sea level will rise in the future are uncertain and  differ alot. The Intergovernment Panel on Climate Change (IPCC) think that sea levels could rise by between 18- 59cm
    • Bangladesh
      • 80% of the land area in Bangladesh is low-lying. Any rise in sea level will submerge large areas
      • This would affect lots of people as Bangladesh has a very high population density (around 1000 people per km2)
      • The situation would be made worse as it's a poor country - the population are vulnerable, with a low capacity to cope
    • The Maldives
      • The Maldives are an extremely low lying set of islands in the Indian Ocean. A rise in sea level of 0.5m would be submerge most of the country
      • Although the population isn't poor, the economy is dependent on tourism, which would be threatened by a rise in sea level
    • Permafrost
      • Permafrost is ground that has been permanently frozen for two or more. It covers around 20% of the Earth's land surface
      • Areas of permafrost are natural sinks of CO2. It's stored as organic material in soil. Thawing of permafrost releases some of this, contributing further to global warming
      • Thawing of permafrost causes the collapse of buildings and pipelines built on it. It may also bring economic benefits to humans though, e.g it's easier to look for and extract natural resources(like fossil fuels) in areas of unfrozen ground
    • Other changes
      • An increase in the frequency of extreme weather events e.g increasing ocean temperatures may mean an increased risk of tropical cyclones over a wider area
      • A change in the distribution of climatic regions e.g colder polar regions may shrink and warmer tropical regions may advance to higher atitudes
        • This affects ecology (the distribution and abundance of organisms). species will have to migrate to remain in a suitable climate and, if they can't migrate, they may become extinct
        • It also affects agriculture - e.g some areas become unsuitable for cultivation as climatic factors such as temperature and the timing of seasons alter
        • regional climate changes may bring benefits to some human activities e.g economic benefits of tourism where the climate has become warmer
    • IPCC
      • The IPCC has produced a number of emission scenarios , which are predictions of how human CO2 emissions will change up until 2100
      • They can put all these different scenarios into global climate models to see how the climate could change with each scenario
      • It is difficult to know how emissions will change, i.e which emission scenario is most accurate
      • We don't know how much of the emissions will be absorbed by things like natural CO2 sinks
      • The extent of climate change due to natural causes (without human influence) isn't known
      • We don't know what attempts there will be to  manage the impacts of climate change, or how successful they' be
    • Tipping point
      • Climate change could reach a tipping point - where a slight rise in temperature would cause catastrophic and irreversible changes to the environment, creating a much more hazardous world
      • This may happen because of positive feedback loops - where a change in the climate is speeded up by the impacts it's already caused
        • Global warming causes melting of Arctic sea ice. As sea ice it leaves darker sea water in it s place. Sea water has a lower albedo (the amount a surface refects the sun's radiation) than ice, so more radiation is absorbed by the water. This warms the water, which causes more ice to melt, and so on

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