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2010 - International Year of Biodiversity
One word that is often used when talking about environmental problems is “biodiversity”. “Diversity” means difference of variety so “biodiversity” describes the whole range of the different varieties of living things on this earth. Biodiversity can be found everywhere – it includes animal species, plant species, genes, ecosystems and landscapes.
Why do we need to conserve biodiversity?
When developing new medicines. Modern researchers are looking more and more towards our natural biological resources. Many animal and plant species have been useful in the past for finding new treatments and cures. One of the most famous examples is digitalin which is derived from the foxglove and is used to treat heart conditions. Another is vincristine, taken from the rosy periwinkle of Madagascar and used to treat childhood leukaemia. Many more medicines have been derived from species found in rainforest areas and it is possible that many species could hold the answer to future medical cures – so the more species that are conserved, the more chance there is of discovering something of medical value.
In the past, farming has played a part in creating and conserving habitats with a rich variety of species. Woodland clearance, hay meadows, different crop varieties, hedgerows and low-intensity grazing have all helped to create the landscapes we see today in most parts of Europe. This type of farming created a wide variety of new habitats, some if which were richer in species than the landscapes (such as woodland) which they replaced. Farming had changed the landscape but it had preserved biodiversity.
In the last 50 years a however intensive farming has developed and now only the most productive species of crops and animals are being grown and reared. This means that many different varieties of domestic animals, fruit and vegetables are in danger of becoming extinct.
If farmers are growing only one type of corn it is more difficult for that crop to resist attack by disease than if the farmer was growing lots of different types – since different corns may be susceptible to different diseases. Therefore the more species we have of plant and animal, the greater the chance that they can resist different disease, pests or other environmental changes.
Biodiversity is of great importance in order to maintain stable ecosystems. An ecosystem is a group of life forms that live together in a balanced and stable community. If there is a sudden change in that community’s environment, the balance of the community may change which may cause it to be destroyed.
The destruction of ecosystems can have a very serious effect both on local and global levels. Rainforests, for example, contribute both to the process of soil formation and help to regulate the climate through photosynthesis – both producing oxygen and absorbing carbon dioxide. Wetlands act as sponge-like reservoirs in dry weather and help to filter and purify water. Coral reefs and mangrove swamps protect the land that they surround by reducing the effects of erosion.
The destruction of rainforest causes erosion, loss of valuable species and changes in climate.
Biodiversity and the protection of our ecosystems is also important to us all as individuals. We can all appreciate the beauty of biodiversity whether we are looking at a view, rock-pooling, going for a walk in a wood or sitting in a garden. Human beings like to live in a varied natural environment with open spaces to walk and play in, trees for shade, colourful flowers, clean water for swimming and paddling, birds and animals. What would our world be like without trees?
There is also an ethical side to maintaining biodiversity. Many people feel that it is their duty to pass on the same natural world to their children that they have enjoyed. Others think that species themselves have their own value and right to exist whether humans need them or not.
Our landscapes also reflect our history and contribute to our sense of belonging and our natural world has inspired our imagination, poetry and art for thousands of years.Threats to Biodiversity
One of the most serious threats, both locally and globally, to biodiversity is pollution. Pollution occurs when substances are released into an environment where they can have a harmful effect on living and non-living things. Human activities can pollute both on a local and global scale and may affect water, soil and air, three of our most important natural resources.
Water – with sewage, fertilisers, toxic chemicals and oil.
Soil – with pesticides, waste, herbicides and toxic chemicals (which may be washed from the land into water)
Air – with smoke and gases such as sulphur dioxide.
Many of the substances which cause pollution are not necessarily harmful in their proper place. Ozone, for example, is necessary in the stratosphere in order to protect us from the sun’s harmful UV-B radiation but a lot of ozone present at ground level pollutes the air we breathe and causes health problems such as asthma.
Species such as the corncockle, poppy and cornflower that used to be common in our cornfields are becoming rare as more agricultural chemicals are used.
It is only quite recently that the global effects of pollution have been discovered. Problems like global warming and acid rain are not as noticeable as oil spills and sewage on beaches and they don’t sound as frightening as nuclear accidents – but all of these, from supermarket trolleys in rivers to gases high up in the atmosphere, have a polluting affect on our ecosystems.
Agriculture, waste and energy production are just a few of the ways in which we pollute our planet…….
Energy and Fossil Fuels
In Britain we all use energy in the form of electricity, gas and petrol to help us in our daily lives. Industrial processes also use large amounts of energy and all this energy has to be produced somehow. Throughout the world, as more countries become industrialised and more people adopt a consumer lifestyle, our need for energy is increased.
Coal, oil, and gas are all fossil fuels. The Earth’s supply of fossil fuels is limited, once they are used up they cannot be replaced, so they are called non-renewable energy resources. Most of the energy used by humans comes from non-renewable resources and mainly from fossil fuels. There are still quite large reserves of coal in the UK but if we carry on using oil at the rate that we do today all the world’s oil and most of its natural gas supplies could be used up by the year 2050!
Fossil fuels release energy when they are burned, unfortunately, they also release carbon dioxide, sulphur dioxide and nitrogen oxide all of which have polluting affects on the environment. Carbon dioxide is one of the gases which contributes most towards the greenhouse effect.
1. The heat from the sun warms the surface of the earth.
2. The earth’s heat is radiated back, away from the surface.
3. Some of the heat radiated back from the earth is reflected off the layer of “greenhouse gases”.
4. This heat remains within the earth’s atmosphere, gradually increasing the earth’s overall temperature.
Gases such as carbon dioxide, methane, nitrous oxide and chlorofluorocarbons (CFCs) appear naturally in the atmosphere but, as a result of human activities (mainly the burning of fossil fuels), these gases have accumulated. The gases than act in the same way as a pane of glass in a greenhouse, letting the sun through to heat the earth’s surface but trapping the heat as it is radiated back. This alters the heat balance of the Earth and gradually global temperatures rise. This is known as global warming. An increase of just a few degrees Celsius in global temperatures could cause a change in climate: more frequent and stronger storms and hurricanes, droughts and widespread flooding as the polar ice-caps start to melt. These climate changes all threaten the world’s ecosystems.
Sulphur dioxide and nitrogen oxide cause a different problem. As they are passed up into the sky these gases react with the tiny droplets of rain in clouds, making them acidic. The rain from these clouds then falls as weak acid which is why it is known as acid rain. The effects of acid rain are far reaching, often the pollution is carried for thousands of miles before it falls as rain. Acid rain can damage trees and plants directly and is also washed into rivers and lakes, where it may kill animals and plants. It also damages stonework and metalwork on buildings.
Fossil fuels are not the only resource we have from which we may produce energy. Nuclear fuel is one alternative which is being increasingly used. Nuclear power stations don’t produce nearly so much pollution in the form of gases such as carbon dioxide or sulphur and nitrogen dioxides. The main problem associated with nuclear power is how to safely store and dispose of the radioactive waste that it produces. People also worry about risk of accidents in nuclear power stations such as the one at Chernobyl in 1986. High level radioactive waste must be stored very carefully as it will remain radioactive for hundreds of years. Nuclear power stations have only been developed relatively recently so many of the possible pollution problems are still unknown.
It is not only nuclear waste that has to be stored and disposed of, all sorts of other processes create waste products. Agriculture, industry, sewage and individual households together produce mountains of waste – so where does it all go?
Farmers add fertilisers to the soil in order to increase the nutrients available in the soil. Fertiliser that is not absorbed into the soil or taken up by the roots of plants is waste, and may be washed into rivers and lakes. Fertiliser, though it may be good for the farmers’ crops, becomes pollution when it is washed into rivers. The nutrients present in the fertiliser encourage the growth of bacteria and algae in the water. As the bacteria increase they use more and more oxygen from the water until there us none left for fish and other aquatic animals and plants – so eventually they die of suffocation. This process is called eutrophication.
As the population of the world grows so does the amount of sewage that we produce. It is very important that our sewage is treated before it is disposed of into rivers and seas. If it is dumped untreated into water it will not only cause eutrophication but it will also spread diseases and poison any people or animals that drink it.
Treating sewage involves several complicated filtering processes and even these have their own waste, a leftover “sludge”, which then has to be disposed of somewhere. Some sludges are used as fertilisers on farms, sometimes the water is removed from them and the remaining substance is burned and sometimes the sludge is dumped out at sea. As you can imagine, each of these methods could also end up causing pollution of some kind.
Each family in the UK throws away an average of 1 tonne of rubbish per year! We throw away leftover food, paper, clothes, packaging and plastic bags, toys, electrical equipment and most of the time we don’t stop to think where all this will end up.
The most common method of dealing with domestic waste is to put it in landfill sites. Layers of waste are tipped into the site, crushed with bulldozers and then covered with soil to stop it blowing away, smelling bad or attracting flies. Gradually most of the waste starts to rot, with bacteria breaking down the biodegradable material.
Domestic waste can become dangerous when it is not properly disposed of. Litter pollution is a growing problem.
An alternative to landfill is incineration (burning) of waste but this can have polluting effects too. As waste is burned it releases toxic substances called dioxins into the air. When the burning is complete 10-30% of the original weight of the rubbish is still left as ash. This ash has to then be disposed of in landfill sites.
Huge amounts of industrial waste are produced by large manufacturing companies and much of this is disposed of in the same way as household waste. Some industrial waste however may be toxic (harmful) and therefore cannot be disposed of in general tips. Instead it is either buried deeply, incinerated (burned), diluted or dumped into the sea in containers. None of these methods are necessarily completely safe. Buried waste could be disturbed by digging or earth movement, containers could crack and toxic waste could leak out into the sea or soil. Burning toxic waste could lead to polluting gases being released into the atmosphere, contributing to acid rain and global warming. It is therefore very important that companies are careful and responsible when making arrangements for disposal of toxic waste.
It is not only pollution that threatens the biodiversity of our planet, another threat is the over-exploitation of natural resources. In other words we use up too much and too quickly. As the population of humans increases, demand for these natural resources grows. Timber is taken from forests without giving them time to regenerate themselves, animals are hunted to the verge of extinction and our oceans are fished without giving the fish population time to recover their numbers.
One of the most familiar of these problems is the destruction of the rainforests. Deforestation endangers biodiversity in several different ways:
As intensive farming has developed, trees and hedgerows have been destroyed to create larger fields for crops, wetlands have been drained and ponds filled in. All these changes have reduced the areas available to many species of animal and plant.
Tourism, one of the largest industries in the world, is another growing environmental problem. As tourists flock to find unspoilt areas, clean blue seas, sandy beaches and historic towns; new buildings are built to accommodate them, mangrove swamps, sand dunes and coral reefs are destroyed to build marinas and golf courses, local lifestyles change and local resources are stretched to their limits.
Freshwater is a valuable resource and even in Britain, where our climate is quite cool and damp, we have been having regular problems with summer droughts. Some of our water comes from underground (aquifers), some from reservoirs and some is pumped out of lakes and rivers. Even when we have long periods of time without rain we still need fresh water to drink, wash and water crops. Industry too, uses huge amounts of fresh water – but it is power generation that uses the most. As ground water supplies get lower and reservoirs dry up more and more water is pumped out of our rivers and lakes and this can have very damaging affects on our freshwater ecosystems.
Habitats are also destroyed everywhere through building more houses, roads, supermarkets and factories, creating more farmland an increased mining and mineral extraction.
As the population of the world has increased, the threats to biodiversity have become ever greater. The world’s ecosystems are being affected and now there is a serious danger of causing permanent damage, not just to local environments but also to the global environment.
As we continue to build, quarry, farm, mine, generate energy, trade and dump waste we are gradually reducing the amount of land available to other animals and plants and to future generations of human beings.
What can we do?
In 1992, just over 170 countries gathered together in Rio de Janeiro for a meeting called “the Earth Summit” to discuss the future of our world. Together they agreed that there was a need to work together, “ in global partnership for sustainable development”.
Since then the phrase “sustainable development” has been used more and more – but what exactly does it mean?
The most common definition comes from a document called the “Brundtland Report” in 1987. It says that sustainable development is…..
“development that meets the needs of the present without compromising the ability of future generations to meet their own needs.”
In other words we must make sure that whatever we do, as populations expand and lifestyles change, we must keep the world in good condition so that our children and our children’s children will have the same natural resources that we have. Natural resources that include: fresh air, clean freshwater, farmland, wildlife, forests, unpolluted seas and a stable climate. A sustainable lifestyle is one that our environment can support without using up these valuable natural resources.
In Rio, 150 countries agreed to promote “sustainable development” and they set out some guidelines, “an action plan for the 21st century.” This action plan was called Agenda 21 and it outlines some ways in which governments and all members of society can start to take action to help make our lifestyles more sustainable in the future.
Waste will always exist but we must find ways to lesson its impact on our environment.
Preserving Natural Resources for the Future
All over the world whole ecosystems are threatened by direct destruction for building, farming an industry. As they are destroyed, more and more species become endangered and more habitats are lost forever.
You can help too!