Effects over nature: Pollution

Effects over nature:

Deforestation

Deforestation has an affect on local climate by affecting biotic factors such as precipitation, the levels of sunlight, and the quality and quantity of soil.

A good example of medicinal use of tropical rain forest plants is the success of the drugs vincristine and vinblastine, developed over the past 20 years from a wild periwinkle found in the forests of Madagasgar. These drugs dramatically improved the effectiveness of treatments for leukemia and other forms of cancer. Since fewer than 1% of tropical plants have been screened for possible use to medical science, ongoing deforestation results in the permanent loss to science of other species before their value can be recognized. 

Desertification

Desertification is the degradation of land in arid, semi arid and dry sub-humid areas resulting from various climatic variations, but primarily from human activities. Current desertification is taking place much faster worldwide than historically and usually arises from the demands of increased populations that settle on the land in order to grow crops and graze animals.

A major impact of desertification is biodiversity loss and loss of productive capacity, for example, by transition from grassland dominated by perennial grasses to one dominated by perennial shrubs. In the southwestern deserts of the United States, semiarid ecosystems dominated by perennial bunchgrasses, including blue grama and black grama, have been replaced by shrublands dominated by creosotebush since the early 1900s. The change in vegetation is thought to have induced desertification in this region. In the Madagascar's central highland plateau, 10% of the entire country has been lost to desertification due to slash and burn agriculture by indigenous peoples. In Africa, if current trends of soil degradation continue, the continent might be able to feed just 25% of its population by 2025, according to UNU's Ghana-based Institute for Natural Resources in Africa.

Soil erosion

*Repeated erosion reduces the fertility of the soil by:

• Removal of topsoil that is rich in crop nutrients and organic matter
• Reduction of the depth of soil available for rooting, and water storage for crop growth
• Reducing infiltration of water into soil, thereby increasing run off and erosion 
• Reducing infiltration of water into soil, thereby increasing run off and erosion 

*Damage to the environment can include:

• Deposition of sediment onto roads, neighbouring properties and into drains.
• Damage to the quality of water courses, lakes and rivers through excess inputs and increased chemical loading.
• Increased run off and sedimentation causing a greater flood hazard downstream
• Sediment in rivers damaging the spawning grounds of fish

Global warming

Climate is an integral part of ecosystems and organisms have adapted to their regional climate over time. Climate change is a factor that has the potential to alter ecosystems and the many resources and services they provide to each other and to society.

Dying coral reefs

Coral reefs are the most sensitive of all ecosystems to global warming, pollution, and new diseases. They will be first to go as a result of climate change. As the most important resources for fisheries, tourism, shore protection, and marine biodiversity for more than a hundred countries, this will be a huge disaster.

Almost all reefs have already been heated above their maximum temperature thresholds. Many have already lost most of their corals, and temperature rise in most places gives only a few years before most corals die from heatstroke.

In 1998 most coral reefs in the Indian Ocean suffered widespread dieback. In 2002 the same happened across much of the South Pacific. These were the hottest and second-hottest years measured, but all other years in the last decade were only a few tenths of a degree less. Survival of most remaining coral is only a question of when the next year as hot as 1998 and 2002 hits. Statistically it's already 2005, although if we're lucky natural climatic fluctuations may postpone it for a few years.

The Status of Coral Reefs Around the World, 2004 notes that:

• 20% of the world's coral reefs have been effectively destroyed and show no immediate prospects of recovery;
• Approximately 40% of the 16% of the world's reefs that were seriously damaged in 1998 are either recovering well or have recovered;
• The report predicts that 24% of the world's reefs are under imminent risk of collapse through human pressures; and a further 26% are under a longer term threat of collapse;

Atmospheric Temperature Rise Predicted

The Intergovernmental Panel on Climate Change, in which more than 1,000 scientists participate from countries around the world, compiled its second report in 1995. The report states that the average temperature on the earth increased by about 0.3 - 0.6 over the past 100 years, and that global warming will further advance if no new measure is taken, raising the average temperature at the end of the 21st century by about 2 (minimum: about 1; maximum: about 3.5), and further in the future. An increase of 2 is not to be dismissed as "only" 2; the scorching heat wave in Japan in 1994 was, in fact, an increase of "only" 1 from the average year.
Even during the ice age, the average temperature was only 3 - 6 lower than today, which underlines the seriousness of a 2 increase in average temperature.

It is possible to predict temperature increases in the Earth's atmosphere based on increasing levels of carbon dioxide .For example, according to the best estimates now available, a doubling in the concentration of carbon dioxide in the atmosphere should produce an increase in the Earth's average annual temperature of 1.5 to 4.5 degrees C.

Migration of people

If global warming occurs, millions of people will be forced to abandon their homes, especially those in low lying coastal areas and along great river systems. Scientists estimate that if global warming were to develop and 1-5% of the population were affected, there would be anywhere from 80-400 million environmental refugees in 2020. An average sea level rise of just 30 cm would force most people in delta regions of the Nile, the Ganges, and the Yantze to migrate. Further, such a rise would result in a loss of 25% of the land in Bangladesh which now has a population of 114 million. Many islands would no longer be able to support their populations. Some of these islands include the Maldives in the Indian Ocean; Kiribati, Tuvalu, and the Marshall Islands in the Pacific Ocean; and some in the Caribbean Sea. The migration crisis caused by global warming would spark other crises, such as civil war, economic breakdown, and disorder. Further, many people will resist more refugees than they believe their country can absorb because of fear of breakdown of social cohesion and national identity. Yet they can only stave off movement temporarily. For example, the rich in countries and cities cannot protect themselves in the long term against these refugees, most of whom will be poor. Further, refugees can cross land borders and enter countries via water routes. For instance, Arabs and African can cross into Europe and Chinese into the sparsely settled areas of the Soviet Union. In fact, the large number of refugees involved would make it difficult to control the movements. We can make efforts now to prepare for the changes, such as grow crops for food that flourish in a carbon dioxide rich environment and build dikes. Moreover, we need to slow population growth, to inspire understanding of the biosphere, and to support sustainable economic development.

Higher sea level

Higher temperatures on the earth cause sea water to expand with heat and glaciers to melt, raising the sea level year after year. A 2 increase in earth's average temperature is expected to raise the sea level by about 50 cm (minimum: about 15 cm, maximum: about 95 cm). A higher sea level intensifies erosion on natural beaches, with particularly serious impact on sandy beaches. It is estimated that a sea level rise of 50 cm would result in the disappearance of about 70% of the sandy beaches in Japan. A sea level rise of 1 meter would swallow about 90% of the sandy beaches in Japan and 100% of the sandy beaches in Osaka Prefecture.
As well, a sea level rise of 1 meter would result in a 2.7-fold increase in land below high tide and a 2.1-fold increase in density of inhabitants on the remaining land. Elsewhere in the world, 80% of some parts of the Marshall Islands and 18% of Bangladesh will be inundated. The percentage of land that will submerge may vary from country to country, but on the whole those living on lowlands will lose their homes and become refugees.

Melting of ice

Globally, higher temperatures cause ocean water to expand and glaciers to melt causing sea levels to rise. Glaciers around the world have already begun to melt at startling rates. The coastal regions of the U.S. that are most vulnerable to higher sea levels are the mid-Atlantic and south Atlantic coasts and the Gulf Coast. Rising sea levels pose a number of serious threats to coastal regions including erosion of beaches, permanent inundation of wetlands and lowlands, increased flooding and storm damage, and salinization of fresh water reserves. The ecological and economic damage is expected to be enormous. More extreme weather events will likely result in billions of dollars worth of damage to coastal property and shipping infrastructure. Warmer ocean temperatures and the flooding of coastal wetlands, which provide habitat for numerous plant and animal species, could ruin coastal and marine ecosystems and cause valuable commercial fisheries to collapse.

• Increase extreme weather events such as tornadoes and hurricanes

POLLUTION

Acid rain harms living things

When acidic air pollutants combine with water droplets in clouds, the water becomes acidic. When those droplets fall to the ground, the acid rain can damage the environment. Damage due to acid rain kills trees and harms animals, fish, and other wildlife. Acid rain can destroy the leaves of plants like in the picture at the left. When acid rain soaks into the ground, it can make the soil an unfit habitat for many living things. Acid rain also changes the chemistry of the water in lakes and streams, harming fish and other aquatic life.

The thinning ozone layer harms living things

Air pollutants called chlorofluorocarbons(or CFCs) have destroyed parts of the ozone layer.The ozone layer, located in the stratosphere layer of Earth's atmosphere, shields our planet from the Sun's ultraviolet radiation. The areas of thin ozone are called ozone holes. Ultraviolet radiation causes skin cancer and damages plants and wildlife.

Tropospheric ozone harms living things

Ozone molecules wind up near the Earth's surface as a part of air pollution. Ozone molecules near the ground damages lung tissues of animals and prevent plant respiration by blocking the openings in leaves where respiration occurs. Without respiration, a plant is not able to photosynthesize at a high rate and so it will not be able to grow.

Causes Toxic Buildup in the Food Chain

Harmful chemicals such pesticides from agriculture and heavy metals like lead and mercury from industries can build up in the food chain, where they reach toxic levels in fish and other sea animals.

Kills Aquatic Life

Polluted water kills fish, shrimp other aquatic life and coastal vegetation e.g. mangroves. This means fewer fish to eat and the loss of livelihood for many.

Causes Algal Bloom

Wastes such as urea, animal manure, vegetable peeling provide food for tiny plants called algae.

The more waste there is the more algae grows, this is called algal bloom. Bacteria feed off rotting algae and in the process use up the oxygen in the water. Fish, crabs and shrimp then die because no oxygen is left in the water for them.

Water Weeds

Deforestation:

• Desertification
• Soil erosion

Global warming

• Dying coral reefs
• Migration of people
• Atmospheric Temperature Rise Predicted
• Higher sea level
• Melting of ice

POLLUTION:

• Acid rain harms living things

The thinning ozone layer harms living things

Tropospheric ozone harms living things

Causes Algal Bloom

• Causes Toxic Buildup in the Food Chain
• Kills Aquatic Life