Since the industrial revolution in the late 1700’s and early 1800’s, humans have been using the earth’s resources extensively for attaining energy and the means of transportation through burning coal, oil and natural gas. These industries have made our lives a lot easier but come at a high price to our Earth by damaging it in numerous ways which in turn will eventually lead to affect us. Acid rain is one of those consequences, and although attention has been brought to this issue globally and measures are being taken, acid rain remains a significant threat to numerous aspects of our earth and will only get worse while we still rely on the use of non-renewable and unsustainable practices.
Initially, acid rain was only occurring around industrialized sites, but due to the increase in power plants and industries in the world, atmospheric emissions are being transported regionally and even globally. Astoundingly, acid rain has even been identified as one of one of the most serious environmental problems of transboundary nature (pollution originating in one country but affecting neighbor countries through transportation of air or water).
What is Acid Rain?
Acid Rain is the explanation through which acid falls from the atmosphere in the form of rain, snow hail or fog. It is the washout of oxides of sulfur, nitrogen and other constituents present in the atmosphere. These oxides largely originate from coal-fired powered stations, smelters (producing SO2) and motor vehicle exhausts (NOx).
The degree of acidity is measured by pH value. A normal pH for rain is around the 5-5.5 range. This is slightly acidic because rain slightly reacts with atmospheric carbon dioxide to produce carbonic acid as well as the small amount of nitric acid which is produced by the oxidation of nitrogen in the presence of water during lightning storms.
Effects on Soil
The soil is crucial for life to flourish and grow, as every single plant needs and depends on it for their nutrient and water supply. This means, that we need soil to function effectively for us to grow food and live in a healthy environment. The soil system is very complex and dynamic so even the smallest of changes can have large consequences.
Due to the reactions between these oxides (SO2 and Nox), and other constituents of the atmosphere, protons are released into the soil causing soil acidity. The soil’s pH consequently lowers and in turn leaches nutrient cations (like potassium (K), magnesium (Mg) and calcium (Ca) in the soil) away and increases the availability of toxic heavy metals. In turn, this leaching leads to a nutrient deficiency in the affected soils and therefore reduces soil fertility which in turn impacts negatively on plant growth and the productivity of forest trees and crops. Nutrient cycling, a crucial aspect of soil health and functioning, is also negatively affected by acidification of soil because it disorientates the decomposition of the litter of certain tree species such as spruce, pine, birch and other cellulose-rich materials.
Effects on Aquatic Ecosystems
Unsurprisingly, acid rain makes water bodies acidic and in turn, affects all components of aquatic ecosystems, whether it is the plankton, amphibians or the fish. Some of these symptoms included fish showing increases in mortality rate, reproductive failure, reduced growth rate skeletal deformities and increased uptake of heavy metals.
When the pH gets below 5.5, the number of snails and phytoplankton start to fall and once reaching a pH of 5.2, they start to disappear. Zooplankton starts to disappear at a pH of 5.0 and then below 4.0, more fish species declined rapidly because embryos failed to mature at this level of acidity.
Effects on Forest Trees & Crop plants
Acid rain also has a detrimental effect to forest trees and does so in two ways, via through foliage or through the roots. Acid rain causes symptoms such as the damaging of plant tissue, reduced canopy cover and overall tree death. In crop plants, acid rain impacts various physiological and morphological characteristics such as their photosynthetic rate and the stomata conductance which reduce overall crop yield.
What is concerning about acid rain affecting crop plants is that this is the food we grow to feed the world. With an increasing population and climate change bringing us challenges such as acid rain, it impairs farmers, all over the world, the ability to increase current food supply demands. Because by 2050, farmers are expected to double food supply to feed a population of 9 billion people…that is pretty intimidating when normal farming conditions become challenging.
How do we reduce Acid Rain?
Below are some ways we can reduce the prevalence and severity of acid rain:
- Liming – Adding lime to water bodies and soil can help eliminate some of the symptoms of acidification but must be done repeatedly to restore water and species health.
- Emission control – The most important means of reducing and eliminating acid rain is the reduction of SO2 and NOx emissions as this is where the problem arises. It is unfortunately not common for there to be fuel low in SO2 but there are techniques available to reduce S02 from emissions from non-ferrous smelters.
- Policy Intervention – In the 1970’s when the effects of acid rain were severely impacting the ecosystems of Europe and America. NAPAP, an acid rain programme was organized to achieve significant environmental and public health benefits through reductions in emissions of SO2 and NOx, the primary causes of acid rain.
Overall, with the rapid economic development and energy consumption throughout the world due to population growth and dependency on energy, fossil fuel consumption has increased significantly during the last few decades. Use of fossil fuel is the major cause of large-scale generation of acid precursors in the atmosphere and steps need to be pushed to significantly reduce our reliance on non-renewable sources of energy.
What Can You Do To Help?
- You can participate in public protests that want an end to fossil fuels
- You can donate to organizations that are that push against fossil fuels
- You can vote for a party that pushes for renewable energy
- You can learn more about this issue and talk about it with your friends and family. Education is powerful and with it, we can make small but powerful change within our own space of community and let it spread!
Thank you for taking an interest in the environment and educating yourself on world issues like acid rain. It is through education where change happens and it is important to find out ways you can make small but powerful changes in your life to make an impact.
The Earth Co.