Although local and global environmental issues have become part of the mainstream in recent years, for many people there is still confusion as to what these issues actually are. With so much publicity and focus given to the controversies of climate change and global warming, it is easy to be unaware of the other main issues.
To simplify, local and global environmental issues can be described under four categories; resource depletion, pollution, biodiversity and sustainability.
Resource Depletion
Most people have heard of the concepts of renewable and non-renewable resources. As human beings we need them to survive and progress. Non-renewable resources such as coal, gas, oil and minerals are finite and therefore non-renewable. Once they have been used, they are gone forever to all intents and purposes. Renewable resources such as water, wood, animals and plants can be re-used or replaced.
Globally the world consumes more non-renewable resources than renewable ones and presently more renewable ones than we can regenerate quickly enough. Because of this inefficiency, and especially considering a rising global population and consumption in rapidly developing economies, there will come a tipping point where the planet cannot support the world’s consumption and use of natural resources. This is why it is considered important to preserve those resources through re-using, recycling or greater efficiency.
Pollution
As human beings use resources inefficiently, there is inevitably a level of waste that must be released back to the environment, whether light, heat, noise,or substances. These are released into three environmental media – water, land and air. Pollution can be defined as when these releases harm people, wildlife or property.
- Water Pollution
Clean water is necessary and vital for human life, but it is also used by industry and homes for washing, cooking, cooling or taking away sewage and effluent. This means that water is over-extracted or polluted.
Over-extraction
When too much water is extracted from the hydrological cycle, whether from streams, lakes or elsewhere; it affects the Earth’s natural water purification process. Pollution concentrations increase during hot, dry weather and wildlife is killed.
Oil, Agricultural, Industrial and Domestic Water Pollution
Oil is very toxic to aquatic and marine wildlife, especially organisms such as plankton that large organisms like whales rely on. Oil also covers sea birds and other marine wildlife and inhibits their survival as they can’t maintain their natural body coat. A cover of oil on the water surface also stops oxygen entering meaning that wildlife beneath the surface can’t breathe and therefore dies.
Agriculture uses pesticides and fertilisers that get washed into groundwater, rivers and lakes. This causes an excessive concentration of phosphates and nitrates that may cause cancer and other serious diseases. Also, fluid from silage has lots of organic matter that can reduce the oxygen levels in rivers and lakes. The reduction of oxygen levels is bad for aquatic wildlife.
Industry emits waste water (effluent) into water courses. If it is organic, again it causes deoxygenation, whilst if it is non-biodegradable the foam can reduce oxygen entry to the water course. If the effluent water is too warm it will also reduce oxygen content.
- Land Pollution
Land pollution can be particularly damaging to humans if it incorporates toxic substances that can be inhaled, ingested or contacted with the skin. If this toxic material is filtered through the land it can enter water supplies, affecting humans and wildlife that use it. It can also give off gases when decomposing, causing air pollution.
Land Pollution includes; illegal dumping (fly-tipping), landfill sites, waste tips from industry, and contaminated old industrial sites.
- Air Pollution
Motor vehicles, power stations and industrial processes emit dust, smoke and harmful gases into the atmosphere. This might cause increased childhood asthma as well as general breathing difficulties. This is more pronounced in urban areas.
Ozone layer depletion
Ozone is a gas found high up in the atmosphere that protects the Earth’s surface and human beings from harmful ultraviolet light from the sun – the type of light that causes skin cancers. It is thought that ozone is destroyed by human-made gases such as CFCs (chlorofluorocarbons) and halons, many of which have been banned in some countries these days. Typically they are/were found in aerosols, refrigerators and air-conditioners.
Acid Rain
When fossil fuels like coal or oil are burned, they release oxides of sulphur and nitrogen. When these oxides react with rainwater it increases the acidity of the water. When this rain falls it can directly kill forests and vegetation, as well as releasing toxic metals in soil and surface water.
Noise pollution
When noise is unwanted or harmful to humans it can be said to be pollution. Commonly this is emitted by road and air traffic as well as industry and construction. The effect is much wore during unsociable hours when it interrupts the rest patterns of humans.
Climate Change
This is of course one of the more controversial concepts, with whole books having been written arguing both for and against its links to human causes. Basically, the Earth contains greenhouse gases (e.g. carbon dioxide, water vapour, ozone, methane, nitrous oxide and chlorofluorocarbons) that keep it warm. Air pollution through burning fossil fuels as well as the destruction of “carbon sinks” such as forests or peat bogs creates a change in the proportion and balance of these gases in the atmosphere. This stops heat from escaping back into space and so average global temperatures increase, known of course as “global warming”.
Global warming (whether natural or human-induced) is seen as a major issue as it would disrupt weather patterns (affecting agriculture and food supplies), increase sea levels (affecting living places, freshwater supplies, agriculture or vital installations on coastlines or low-lying areas) and spread killer diseases that are confined to hot countries, such as malaria. Of course it will also cause wildlife to migrate to areas where it can survive, or worse still cause extinctions.
It is important to remember that carbon is completely natural and indeed vital to life on Earth and is often naturally emitted by volcanic eruptions, fires and rock weathering – only to be subsequently recycled by natural processes. The problem is when human activities release too much of previously stored carbon to the atmosphere and disrupt the balance.
Biodiversity
Biodiversity is basically the number and variety of plant and animal species on the earth. This number is important because of the important services they provide to ecosystems and humans such as: medicines, food, shelter, aesthetics (people like nature and greenery), food and flood reduction (by water absorption).
It is being threatened by several processes including; habitat destruction (e.g. deforestation), invasive species (e.g. the non-native grey squirrel has caused the threat to the native red squirrel in the UK), pollution, population expansion (leading to construction and conflict with nature) and over-harvesting (because of the planet’s growing population putting a strain on existing food resources).
The greater the biodiversity, the stronger the ecosystem and ecosystems are the natural method of the Earth to sustain all life. So by causing extinctions of plants and animals, we are threatening the health and maintenance of all life. Importantly, there are natural resources which we are yet to discover or have not yet discovered their potential to help us. So by reducing biodiversity, humans might just be destroying a life-saving drug or natural fuel that we are not yet aware of.
Sustainability
Sustainability or sustainable development is the concept that we should continue to economically develop, but not at the expense of future generations or the environment. Therefore human beings should not use more resources than can either be regenerated or replaced. Nor should they use resources in a manner that causes destruction to vital ecosystems or creates pollution that causes parts of the planet to be inhabitable for future generations.