Climate Change: Carbon footprints and cycles

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Climate Change Carbon footprints and cycles
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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?

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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
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Climate Change Carbon footprints and cycles

• Variations of the mean surface temperature during
  the last 140 years

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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?

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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.

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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?

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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)
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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.

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Climate Change Carbon footprints and cycles

• The carbon cycle Anthropogenic versus natural
  carbon emissions
• The natural carbon cycle

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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)

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Climate Change Carbon footprints and cycles

• Anthropogenic CO2
• The global budget of CO2 for the 1980s showing
  average annual values in GtC y-1.

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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)

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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.

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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?

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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/