Question

A).i.Explain how greenhouse effect raises the temperature of the troposphere

ii) N₂O is a greenhouse gas. Draw the IR active vibrations of N₂O. The frequency of the bending vibration is 596 cm^-1, calculate the wavelength of light that N₂O can absorb due to this vibration (show your working).6 marks.

iii).Discuss what is meant by the term “global dimming”.

(2 marks)

(iv) Explain why chlorofluorocarbons make a significant contribution to the enhanced greenhouse effect even though their concentrations are in the order of 10 to 300 parts per trillion (ppt) compared to the 400 ppm concentration of carbon dioxide.(3 marks)

(v) Suggest reasons why the international community has not been successful at solving the problem of increased CO₂emissions.

                                                                                                                            

Answer 1

i) The Earth gets energy from the sun in the form of sunlight. The Earth's surface absorbs some of this energy and heats up. That's why the surface of a road can feel hot even after the sun has gone down—because it has absorbed a lot of energy from the sun. The Earth cools down by giving off a different form of energy, called infrared radiation. But before all this radiation can escape to outer space, greenhouse gases in the atmosphere absorb some of it, which makes the atmosphere warmer. As the atmosphere gets warmer, it makes the Earth's surface warmer and as the troposphere is the lowest layer of Earth's atmosphere and site of all weather on Earth,it will also get warmer and the temparature rises in the troposhere.

iii)Global dimming: is defined as the decrease in the amounts of solar radiation reaching the surface of the Earth. The by-product of fossil fuels are tiny particles or pollutants which absorb solar energy and reflect back sunlight into the space.

iv) CFCs are not very abundant (only constituting 1/billion of the atmosphere as a whole), but are "extravagantly destructive. One pound of CFCs can capture and annihilate seventy thousand pounds of atmospheric ozone. CFCs can also hang around for a long time -- about a century on average -- wrecking havoc all the while. They are also great heat sponges. A single CFC molecule is about 10,000 times more efficient at exacerbating greenhouse effects than a molecule of CO2.

To explain why?? Example:

The climate in the Antarctic stratosphere has been completely controlled by CFCs and cosmic rays, with no CO₂ impact. The change in global surface temperature after the removal of the solar effect has shown zero correlation with CO₂ but a nearly perfect linear correlation with CFCs - a correlation coefficient as high as 0.97.”

v)

a) Implications to all aspects of a nation-state's economy - The vast majority of the world economy relies on energy sources or manufacturing techniques that releasegreenhouse gases at almost every stage of production, transportation, storage, delivery & disposal while a consensus of the world's scientists attribute global warming to the release of carbon dioxide and other greenhouse gases. This intimate linkage between global warming and economic vitality implicates almost every aspect of a nation-state's economy

b)Industrialization of the developing world - As developing nations industrialize their energy needs increase and since conventional energy sources produce carbon dioxide, the carbon dioxide emissions of developing countries are beginning to rise at a time when the scientific community, global governance institutions and advocacy groups are telling the world that carbon dioxide emissions should be decreasing. Without access to cost effective and abundant energy sources many developing countries see climate change as a hindrance to their unfettered economic development

c)Consensus-driven global governance models - The global governance institutions that evolved during the 20th century are all consensus driven deliberative forums where agreement is difficult to achieve and even when agreement is achieved it is almost impossible to enforce

d)Well organized and funded special-interest lobbying bodies - Special interest lobbying by well organized groups distort and amplify aspects of the challenge (environmental lobbying, energy industry lobbying, other special interest lobbying)