Environmental Issues – Human Impact on the Environment

Natural Processes on Earth

There are many, many natural processes occurring all the time on earth. The seasons change, the climate changes, so many natural elements are recycled such as oxygen, carbon, nitrogen, sulfur and water, weathering processes break down rocks and minerals, and we occasionally experience volcanos, earthquakes and other natural phenomena.

Some of these processes are occurring continuously, some change from time to time, some are predictable, some occur all of a sudden without any warning. And they all occur without any intervention from humans. (See also: various topics under Earth and Space Sciences). This is nature!

However, humans have increasingly been having an impact on these natural processes as a result of their civilization spread and industrial progress. These impacts have been triggered by factors such as over-population, burning fossil fuels and deforestation, leading to soil erosion, poor air and water quality (collectively termed “Environmental Pollution”) and a relatively recent phenomena termed as “Climate Change”. Let us explore some of these impacts in greater detail.

Loss of Habitat

Many human activities such as agriculture, mining, harvesting, construction and urban development to name a few, result in Habitat Reduction or Habitat Destruction whereby species of plants and animals are displaced or eliminated from their natural surroundings. This reduces biodiversity and abundance of species and affects the health global ecosystems. The tiger, cheetah, mountain gorilla, Asian elephant and Javan rhinoceros are all in threat of extinction because of these human activities.

Over-hunting and Over-fishingare also activities by humans, which cause serious reduction in species population, sometimes to the point of extinction. They can cause imbalance in the food chain or food web (see also: Life Sciences – Interdependence of Organisms). Overhunting is responsible for the extinction of elephant birds, giant lemurs, giant kangaroos and moas. Overfishing is resulting depleted species of sharks, monkfish, Atlantic halibut and bluefin tuna. By-catches, which are animals caught by mistake during fishing, also erode aquatic species such as dolphins, sharks, turtles and whales.

Invasive or Non-native Species have often been introduced either accidentally or on purpose by humans.Sometimes this can be beneficial to native species, but more often, such species can overcome native species by predation or competing for the same food, again reducing biodiversity.

Climate Change

In recent decades scientists have discovered a new phenomenon caused by Global Warming whereby average conditions such as temperature and rainfall change in a region over long periods of time. It is believed that the earth’s surface has warmed considerably over the past century, and the warmest years have been in the last couple of decades. As a result, glaciers are melting at a faster rate, average sea levels are rising, ocean temperatures are rising, all with unpredictable and sometimes disastrous effect on weather patterns and climate around the world.

Human activity has increased carbon dioxide emissions which have driven up temperatures. This is termed as the Greenhouse Effect. Rainfall and hurricane patterns have changed as a result, known in some regions as the El Niño Effect(See also: Factors that affect climate).

Our understanding of climate change is still evolving and the entire impact and consequences are yet to be played out and felt. Scientists are continuously monitoring the various parameters in our environment while efforts have been made to scale back carbon dioxide emissions, reduce deforestation, and shift to renewable energy from our dependence on fossil fuels.

Check Point

1. Poor air, water and soil quality is often the result of ________.
2. Species of plants and animals displaced or eliminated from their natural surroundings is termed as ________.
3. Radiation Pollutioncan occur due to ________ and ________.
4. Over-hunting and Over-fishing can cause –
   1. Reduction in species population
   2. Extinction
   3. Imbalance in food chain
   4. All of the above
5. Global Warming can be evidenced by the ______ effect and the ______ effect.

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