Negative human impacts
As the human All of the members of a single species that live within a geographical area. increases, the volume of waste and Contaminating the air, water or ground with harmful substances. that is produced also increases. Polluting an The living organisms in a particular area, together with the non-living components of the environment. harms or kills the organisms that live within it.
In modern society, humans manufacture an increasing number of products and replace them more often. This is not An activity which does not consume or destroy resources or the environment. - many natural materials, including fossil fuels, will soon run out and many people argue that there is already too much waste.
Water pollution
In some instances, Poisonous. waste or sewage can end up in, or be discharged into streams, rivers and lakes, causing damage to aquatic life and serious illness in humans that may drink the contaminated water.
Some farmers use too many fertilisers, which can run off fields during heavy rain. This can pollute nearby streams and rivers leading to 'Hyper-nutrition' resulting from fertiliser pollution of aquatic ecosystems..
Air pollution
The process of burning by heat. of fossil fuels and other fuels releases carbon dioxide. This contributes to the The retention of heat in the atmosphere caused by the build-up of greenhouse gases., producing The rise in the average temperature of the Earth's surface. and leading to The long-term alteration of weather patterns..
Combustion of fossil fuels also releases sulfur dioxide and nitrogen oxides which can cause acid rain. Air pollution can also be caused by tiny particulates from smoke which can cause A type of pollution that is a mixture of smoke and fog.. Some of the world's major cities like Delhi in India and Karachi in Pakistan have dangerously high levels of air pollution.
Land pollution
The rubbish we throw out that is not Reusing materials or reprocessing waste materials to produce new materials. goes into a land fill. These are huge holes in the ground into which our rubbish is dumped. Some things like batteries cannot be put into Places where refuse is buried underground. because of the toxic chemicals they contain. They must be recycled. Other land pollution comes when some people dump rubbish in public or other private places, often to avoid paying for it to be disposed of. This is called fly tipping and is illegal.
Land use
The larger the human population gets, the more land we require. More houses must be built, more resources found, more food must be grown and more waste is produced. This often means less space and fewer resources for other animals and plants.
The range of animals and plants in a given area. is significantly reduced when land is cleared for human uses, such as building, quarrying, farming and waste disposal. A reduction in biodiversity occurs when an area of rainforest is cut down to grow crops.
Deforestation
For thousands of years, humans have been deforesting small areas of woodland to build their own houses or grow crops to feed their families. However, in recent years the increase in the human population and development of industrial machinery has meant that much larger areas have been cleared. This is often by large companies who deforest to provide land for cattle, rice fields growing crops for food and A type of energy source derived from renewable plant and animal materials, eg ethanol (often made from corn in the United States and sugarcane in Brazil), biodiesel (vegetable oils and liquid animal fats) and biogas (methane from animal manure)..
The cutting down of trees and forests to allow a different land use. destroys the A place where plants, animals and microorganisms live. of the organisms that live there and through this kills individuals of many A type of organism that is the basic unit of classification. Individuals of different species are not able to interbreed successfully.. Scientists estimate that several hundred species of plant, animal and insect are lost each day partly as a result of deforestation. This means that deforestation is causing extinctions and dramatically reducing biodiversity.
Peat bog destruction
A muddy area of land. are very wet areas of land without trees in which many types of moss grow. They are Having a pH lower than 7. and often have very low levels of nutrients. Here The process of breaking down material to release nutrients back into the soil. is very slow and peat is formed from partially decayed plants.
For many years peat was removed from bogs for gardeners to add to their soil or in some countries, to burn as fuel. This dramatically reduced biodiversity. Because peat takes such a long time to form, it is a A resource that cannot be replaced when it is used up, such as oil, natural gas or coal. energy resource like fossil fuels.
Peat bogs are poorly drained areas made up of partially decomposed organic matter due to waterlogging. are a very important store of carbon. We call them Anything that absorbs more carbon than it releases, whether natural of artificial.. If all the peat was removed and burned this would quickly release a huge volume of carbon dioxide into the atmosphere and contribute to the greenhouse effect.
The greenhouse effect
Without the greenhouse effect, it is estimated that the The average. temperature on Earth would be -18°C and there would be very little or no life. So the greenhouse effect itself is a good thing. The greenhouse effect traps some of the energy from the Sun, which keeps our planet at a suitable temperature for life.
The problem is that the increased release of greenhouse gases is causing an increase in the greenhouse effect called the enhanced greenhouse effect.
Carbon dioxide, water vapour and methane are amongst the most common greenhouse gases. Since the start of the The process that transformed manufacturing from handmade to machine-made, mass-produced goods using water, steam and coal power transported by canal, rail and steamship. Britain was the first country to have an Industrial Revolution., in about 1750, the levels of carbon dioxide have increased by 40%.
Global warming
Global warming is the increase in the mean temperature of the Earth. The ten hottest years since records began have been in the last 30 years. The mean increase in the last 100 years has been less than 1°C. This might seem small, but is enough to have devastating consequences on many species in different parts of the world.
As the percentage of carbon dioxide in our atmosphere has increased, so has the Earth's mean temperature.
Note that the shape of the first graph showing the amount of carbon dioxide in the atmosphere is 'exponential' and is a similar shape to graphs showing human population change over the same time period.
When comparing graphs such as changes to carbon dioxide levels and temperature against time, note that the axes are drawn to different scales, and do not start at '0'.
The consequences of global warming and climate change are:
- melting of the polar ice caps
- the rise in sea level that will flood many parts of the world and may one day threaten many cities such as London, New York and Amsterdam
- weather patterns will change with more unusual weather:
- long-term, in the UK, summers are expected to become hotter and drier, and while plant productivity will increase, some native species of tree in our woodlands may struggle to survive the warmer conditions
- animals will migrate towards the poles to find habitats with suitable temperatures:
- in the UK, we are already seeing some species, eg of butterfly, moving northwards, while numbers of some northern species are decreasing because of the warmer conditions
- tropical diseases may become more common in other regions, such as Europe
- many species will become A species that has completely died out.
