CARBON - Threats to forests and the ocean by human activity

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  • Ocean acidification
    • caused by the oceans acting as carbon sinks in the C Cycle. This decreases the pH (fallen from 8.2 to 8.1 by 2015).
      • Coral reefs take CO2 and turns into CaCO3, forming rocks and making the ocean a big carbon store. these stop growing when the ocean pH drops below 7.8
        • coral bleaching occurs when surface waters get too warm and pH gets too low- coral expel the algae  living in their tissues causing the coral to turn completely white. (Great Barrier Reef, Australia).
    • Threats by human activity
      • HEALTH OF FORESTS - being challenged in 3 ways:
        • 1. Deforestation, 2. the poleward shift of climatic belts, and 3. increasing drought.
          • DROUGHT in the Amazon
            • Amazon is a giant climate regulator by pumping 20 bil tonnes of H2O into the atmosphere every day. Humidity lowers pressure, allowing moisture to reach all over the continent.
            • in 2005 and 2010, droughts meant that degraded the forests and had knock-on effects.
            • Declines as a carbon store as a result
            • Sequesters less CO2 from atmosphere, enhancing the GH effect.
            • Plays a role in the hydrological cycle.
      • affects FOOD WEBS, meaning 500 million people who are supported by fishing may be affected. (people also rely on fishing for income.
        • ICELAND and JAPAN choose fish as main diet.
      • TOURISM - Caribbean traditionally have scuber diving.
      • RISING SEA-LEVELS in the Maldives means expensive sea-defences.
    • When the water heats it is less able to absorb CO2, reducing PHYTO-PLANKTON ACTIVITY.
  • Impacts of forest loss
    • KUZNETS CURVE - Shows that as income and development increases, the cost of resource exploitation overtakes benefits of resources.
      • Where China are at today is considered the 'tipping point'.
    • 13% of the UK's surface has been forested. The world was predicted to once have 80% forestland (now just 10%).
    • C exchange between atm and soil is affected.


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