Natural systems – Cont’d
WEATHER, CLIMATE, VEGETATION AND SOIL
FOCUS QUESTION
How does the human impact the ecosystem?
Ecosystems are systems consisting of living beings, interrelated among themselves and with their environment. An ecosystem does not exist in isolation. Its existence is dependent upon the components within it and its relationship with external elements.
Humans interact with the world every day, but some of our actions are more harmful than others.
Humans can affect the ecosystem in a negative way, by pollution, waste dumping, over hunting of animals, overfishing, industrial gases, energy use and not using biodegradable products.
NEGATIVE EFFECTS OF HUMAN ACTIVITIES
Air pollution is caused by: Cars Factories Different types of gases (causing the greenhouse effect)
HUMANS POLLUTE
The land, water and air with unwanted refuse.
People lack proper sanitation, which means that drinking water around the world is contaminated with waste and disease.
Open water is often contaminated by agricultural chemicals, fuel from passing boats, and even litter.
Practically over 2.4 billion people do not have access to clean water.
The world population as of 2017 is 7.6 billion, so a quarter of the world’s population is without clean water.
It is rare to find a beach in the world that does not have litter.
In some countries: The smog caused by air pollution is deadly and can block out the sun in a dense haze.
Wood harvesting in rural areas is bad for human health and it is creating wood fuel shortage.
Coal plants produce so much pollution that it is collecting in our atmosphere, causing breathing hazards and affecting the weather.
Humans produce about 300 million tons of plastic each year.
More than eight million tons of that plastic are dumped into the oceans and, in 2017, an estimated five trillion pieces of plastic litter the seas.
Plastic in the oceans has overwhelming effects on marine life.
GLOBAL WARMING
The CO2 emissions that come from burning fossil fuels are affecting the planet’s ecosystem.
The increase of CO2 in the atmosphere traps heat that would otherwise escape into space, increasing the Earth’s overall temperature.
DEFORESTATION
As our population continues to increase, humans create more and larger farms, which means removing the dwindling number of forests.
Forests are also cleared for the lumber that we use to build our houses and to make room for new houses. Eighteen million acres of trees are cleared cut every year for wood. This has devastating effects for the wildlife that once called those forests home. Human waste enters other natural ecosystems where it can cause them to become unbalanced. Sometimes this waste can build up to harmful levels.
Examples of human waste that can affect ecosystems are: Household waste Industrial waste Agricultural waste Gases produced when fossil fuels are burned.
Humans sometimes harvest plants and animals from natural ecosystems and this can also unbalance them. For example, harvesting timber can lead to soil erosion and loss of habitat, while harvesting fish from the oceans can cause species to become threatened and unbalance food webs.
In many countries:
Natural vegetation has been removed and replaced with crops for food or the production of fuels or by grazing animals.
As well as destroying the natural habitat and reducing biodiversity, soil erosion can cause rivers to become silted up (clogged up with silt), plus the lack of shade and the lack of moisture in the soil can cause desertification (when fertile land turns into relatively lifeless desert).
POSITIVE EFFECTS OF HUMAN ACTIVITIES PRESERVATION
The formation of National park service National wildlife refuge system Managed wilderness areas
Ecosystems have been preserved so that future generations may experience the splendour of the landscape, despite environmental pressures such as increased tourist traffic.
POLLUTION CONTROL
Through Clean air Clean water Other regulatory measures (humans have reduced the amount of pollution they create, allowing ecosystems to recover from past impacts such as acid rain).
ENVIRONMENTAL AWARENESS
When human recycle, we use 90 per cent less energy, thereby reducing their environmental impact and benefiting the ecosystem.
Agriculture has a huge effect on our ecosystems:
pesticides and other toxic chemicals used in food production can wash downstream. Killing many types of animals. Polluting our waterways. Making humans ill. Fertilizers can wash downstream, causing ‘blooms’, large populations of algae and bacteria, which can harm fish populations.
The next lesson will be on vegetation and the ecosystem.