Tuesday, 22 March 2011

Describe and comment upon the effects and solutions to the Acid Rain problem [15 marks]

The negative impacts that acid rain has on the environment are numerous and this is why many countries have been prompted to adopt policies that reduce the amount of sulphur dioxide, one of the main pollutants that creates acid rain, that they emit in the hope that it will help to reduce the global impacts acid rain has.
Buildings are always going to be effected by weathering but this natural process is accelerated by acid rain. Buildings, especially those constructed from limestone, sandstone or marble, are greatly affected by wet deposition as, for example, limestone dissolves easily in acid rain and a calcium sulphate layer upon the stone is often formed. This layer is easily removed by weathering and leaves even more stone exposed to acid rain. Dry deposition also contributes to the corrosion of materials used in infrastructure. This has an economic impact as it is very costly to maintain ancient monuments as they are very susceptible to damage by acid rain. In the UK, it has been estimated that over the next 30 years savings of up to £9.6 billion could be made if we reduced our sulphur dioxide emissions by 30%. In the future this is not going to be such a big problem as modern infrastructure does not use materials, like sandstone and carbonate rocks, which are particularly vulnerable to acid deposition.
Acid rain has many ecological impacts and perhaps the most significant of these impacts is to aquatic environments. In areas that experience heavy rainfall, the dry deposits are captured in the surface runoff and increase the acidity of the water. Also aluminium is drawn out of the soil and when this combines with the acid it creates a highly toxic environment for the majority of aquatic animals. This combination often results in an increase in fish mortality, a decrease in both fish growth and reproduction and declines in amphibian populations. The effects of this are often felt further up the food chain too as, although birds and mammals are not directly affected by water acidification, changes to the quantity and quality of their food sources greatly affect them.
Vegetation, especially trees, is also affected by acid rain and in a similar way. The aluminium  that is drawn from the soil makes it very hard for trees to take up water and the acidic rain itself dissolves the nutrients in the soil and then washes them away before the trees have time to take them in and utilise them. Acid rain damages the leaves and needles on a tree which reduces a trees ability to photosynthesise.
It is clear to see that acid rain has had many negative impacts on the environment but some scientists believe that acid rain has a, small, positive impact in relation to climate change. The bacteria, which lives in wetlands and produces a lot of methane, are very vulnerable to changes in the acidity of water whereas other bacteria, that thrive on the sulphurous conditions, compete with methane producing bacteria. It is believed that this has significantly reduced the amount of methane emitted from wetlands. However, in comparison to the negative impacts acid rain has, this benefit is minimal and, as acid rain is a global problem, many countries have implemented measures to reduce the amount of sulphur dioxide they release into the atmosphere.
By reducing the amount of sulphur dioxide countries emit it has enabled them to reduce the acid rain problem. In 1979 a protocol was introduced which stated that sulphur dioxide emissions had to be reduced by 30% by 1997 and this target was met and furthered as in Europe in the 1990’s emissions were cut by 90%. As well as this, sulphur scrubbers were added to every power station chimney in the UK. In the USA most coal-fired power stations have switched to using low-sulphur coal which can be sourced from areas like Australia and they also have installed sulphur scrubbers to the chimneys. They have also implemented a cap and trade scheme and the combination of these measures have cut America’s sulphur dioxide emissions by over 40% since 1980. The amount of nitrous oxides emitted has not been reduced though and instead have been increased due to an increase in the number of vehicles driven globally and the use of fertilisers. Despite this, at present, the acid rain problem is not as prominent as it was 30-40 years ago due to the success in reducing sulphur emissions. However, unless industrialising countries like China and India are given a cheaper and more available option than coal, the acid rain problem is likely to become a big issue again in the near future. 67% of China’s primary energy consumption comes from coal and coal is responsible for 94% of their sulphur emissions. Acid deposition is already an issue in China with 30% of the country experiencing acid rain provoked problems. As they continue to industrialise, and therefore increase their coal consumption, these figures are likely to rise.
Acid rain has many negative impacts on the environment and attempts to control this problem by reducing the amount of sulphur dioxide developed countries emit has worked to a certain extent. However, these reductions have not managed to solve this issue as it has just moved to different areas of the world that are currently industrializing. If help is not given to developing countries to introduce policies to manage their sulphur dioxide emissions or to find other, greener, cheap and available alternatives to coal then the problems that occurred in the 1970’s due to acid rain are likely to resurface in the near future and on a more destructive scale.
Millie's comments on this essay: She suggested that in my second paragraph I could possibly mention how that although modern buildings, because of the materials used, are less susceptible to damage by acid rain compared to ancient monuments and older buildings which are built from limestone, sandstone, marble and other carbonate rocks; that the manufacturing of more modern building materials is likely to increase industrial emissions and therefore the amount of sulphur dioxide and nitrous oxides released into the atmosphere.

Perhaps her most important response to my essay was to suggest that my writing needs to be more succint - unfortunately there is a lot of truth in this. Her concerns surrounding my ability to produce this volume of work in 15 minutes in an exam are also well placed as I realise that there is no way I could ever hope to write this much in an exam. I must admit that it is worrying that I am still struggling, especially as the exam is looming, to write a half decent essay in 15 mintues - tips for writing a minimal amount whilst still managing to get both the depth and breadth required to score highly are desperately needed!

My comments: I don't think that I wrote too badly in the essay and I think that the main issue with it, is that it is not lacking in information and detail but the exact opposite. Although the point that Millie made, in reference to how the manufacturing of modern building materials is going to increase emissions, will be noted I don't think I would necessarily add it to this essay but instead concentrate on cutting out the less important bits and writing more succintly.

 There are clearly some improvements that can be made but what do I think I did quite well? Firstly, I think that my structure was better than it has been in previous essays I have written in class as my introduction was short (an achievement for me!) and served its purpose, I described and commented on both the effects and solutions to the acid rain problem whilst managing to make reference to a few case studies and my conclusion was suffient and readdressed the key points I had previously made in the essay.

If you have any tips, points for improvements or good case studies/statistics that I didn't include but perhaps should of then please comment..........

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