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Climate Change: Carbon footprints and cycles

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Title: Climate Change: Carbon footprints and cycles


1
Climate Change Carbon footprints and cycles
2
Climate Change Carbon footprints and cycles
  • What is climate change?
  • What do you think climate change is?
  • What do we actually mean when we talk about
    climate?
  • How is it measured?
  • What affects it?
  • What effect is climate change having?
  • What can we do about it?

3
Climate Change Carbon footprints and cycles
  • How has the global temperature changed?

Temperatures over the last 400 000 years obtained
from the Vostok ice core, the longest continuous
ice-core record to date
4
Climate Change Carbon footprints and cycles
  • Variations of the mean surface temperature during
    the last 140 years

5
Climate Change Carbon footprints and cycles
  • What questions should you be asking when
    presented with data like this?
  • Where are the observations made? (in towns, open
    countryside, at sea developed countries only or
    mostly northern hemisphere?)
  • How are the measurements made? (is a daily
    average taken, or highest temp of the day, are
    night time temperatures included)
  • What instruments are used? And how are they
    calibrated?
  • How are the global averages calculated?

6
Climate Change Carbon footprints and cycles
  • What affects the climate?
  • The Earths surface is warmer than we might
    expect considering the amount of radiation
    reaching us from the sun.
  • Some gases in the atmosphere absorb infrared
    radiation that has been emitted by the surface.
  • These gases occur naturally in the atmosphere so
    our planet is warmer than expected and can
    support life.

7
Climate Change Carbon footprints and cycles
  • Greenhouse gases
  • - So what are these greenhouse gases?
  • Water vapour carbon dioxide methane nitrous
    oxide and ozone.
  • - How do greenhouse gases absorb the infrared
    radiation?

8
Climate Change Carbon footprints and cycles
This table shows changes in concentrations of the
key natural greenhouse gases and some synthetic
gases (halocarbons that are now banned)
9
Climate Change Carbon footprints and cycles
  • Effect on global climate
  • How do we know that human activities are having
    an effect on climate?
  • Scientists use models to simulate the Earths
    temperature variations and to predict what may
    happen in the future.
  • This diagram shows observed temperatures (red)
    and modelled predictions of the Earths
    temperature over the last 140 years.

10
Climate Change Carbon footprints and cycles
  • The carbon cycle Anthropogenic versus natural
    carbon emissions
  • The natural carbon cycle

11
Climate Change Carbon footprints and cycles
  • Green arrows terrestrial cycle (short
    time-scale, moths/years to decades)
  • Photosynthesis by green plants removes CO2 from
    the atmosphere (CO2 that isnt respired is
    fixed carbon)
  • Respiration of plants returns CO2 to the
    atmosphere
  • Transfer of fixed carbon to the store of dead
    organic matter in soil and detritus
  • Carbon returned to the atmosphere by
    decomposition (respiration of decomposers and
    detritivores)
  • Blue Arrows oceanic cycle (intermediate
    time-scale, up to 1000 years)
  • CO2 dissolves into surface waters (dissolved
    inorganic carbon, DIC)
  • CO2 outgases from the ocean (E and F are
    approximately balanced)
  • Fixed carbon exported to deep ocean (planktonic
    debris, faecal pellets of animals and other
    detritus)
  • Upward movement of deep DIC-rich water
  • Sinking of lower-DIC content surface waters
  • Brown arrows long-term geological cycle
    (hundreds of millions of years)

12
Climate Change Carbon footprints and cycles
  • Anthropogenic CO2
  • The global budget of CO2 for the 1980s showing
    average annual values in GtC y-1.

13
Climate Change Carbon footprints and cycles
  • The two main anthropogenic sources of CO2 are
  • burning fossil fuels and
  • changing land use (nearly 90 attributed to loss
    of carbon from forest ecosystems)
  • So how much CO2 has been released to the
    atmosphere due to human activities during the
    last 200 years or so? (major period of
    industrialisation)

14
Climate Change Carbon footprints and cycles
  • Carbon footprints
  • What do you think should be taken into account
    when calculating your carbon footprint?
  • Now take a look at the carbon calculator.

15
Climate Change Carbon footprints and cycles
  • Reducing emissions
  • How might you reduce emissions of carbon dioxide?
  • (on a personal level rather than industrially
    based)
  • Think about what you now know about the carbon
    cycle and what affects your footprint?

16
Climate Change Carbon footprints and cycles
  • Further Resources
  • If you have found this session interesting why
    not try a course with the Open University
  • Please go to www3.open.ac.uk/study for further
    details or call 44(0) 845 300 60 90
  • http//climateprediction.net/ a project
    launched in September 2003 to explore the
    uncertainty in climate model predictions by using
    distributed computing.
  • Calculate your carbon footprint online at
  • http//www.bp.com/iframe.do?categoryId9032780con
    tentId7060112
  • http//www.safeclimate.net/calculator/
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