CO2

  • CO2, Carbon Dioxide, is the principle Green House Gas (GHG) implicated in climate change.
  • Although present only in low concentrations, as we add more CO2 to our air, it is harder for heat absorbed by the sun to be re-radiated to space, so things tend to warm up.
  • At present, both international aviation and international shipping fall outside the Kyoto agreement.
  • While shipping generates much less CO2 per tonne of cargo moved than any other form of large scale transport, there are measures shipping can take to reduce greenhouse gas emissions
  • For more information on greenhouse gases and ships, visit www.imo.org

INDEPTH
Although only one of many sources of CO2, our burning of fossil fuels, such as oil and coal, adds to the overall burden that has to be removed from the atmosphere by many natural processes, including the photosynthesis of plants. At present, we are overloading these removal processes, and the concentration of CO2 in the air is increasing at 2 – 3 parts per million (or ppm) each year. Already we have raised the concentration from a pre-industrial value of 280 ppm to the current 375 ppm. Since it takes about 100 years for CO2 to be recaptured from the atmosphere, our CO2 emissions now have an impact long into the future.

This is a global phenomenon, so there are concerted efforts by almost all governments (the US is a notable exception) to reach international agreements to reduce CO2 emissions, of which the Kyoto treaty is the first outcome. Many consider our emissions to be a threat to civilisation, so demands to reduce CO2 emissions are certain to grow, and shipping will be no exception. Emissions from both sectors are growing, but this is faster for aviation. Emissions from aviation also include NOx and water vapour, which, because of the height at which they are created, cause significantly greater greenhouse effects. The sectors will come under great pressure to participate in the necessary reductions.

Shipping may be able to recover some of the costs of reductions from the aviation sector, which has more limited options for reductions.