Human activities that affect the Earth and its environment

In previous blog posts we have described how the Earth’s surface and atmosphere have been changed by naturally occurring events and processes.  These have occurred over billions of years with little change in the last 200 000 years until recently.  Any change that has occurred in the last couple of centuries can be directly related to human influences – especially with the demand for natural resources.  These resources such as minerals, metals and fossil fuels are found under the Earth’s surface and as such extracting them involves altering the Earth’s surface.  In doing this there are also environmental and atmospheric implications.

The demand for minerals, metals and fossil fuels have had a big impact on the Earth and its environment.

Mining

In South Wales coal has been mined both deep underground and at the surface.  Leaving large, ugly and unsightly areas on the landscape.  This is an open cast mine in Ffos Y Fran, Merthyr Tydfil.  The town and the Beacons National Park are visible in the background.

The Bingham Canyon in Utah, USA, is the biggest hole in the ground on Earth.  It has been dug to extract copper ore.

These mines have a big effect on the local environment with dust and noise pollution from the digging and blast processes, noise pollution from the transport vehicles working on site and those that leave the site to deliver product.  These mines also produce tonnes of waste rock each day (250,000 tonnes in the case of Bingham) which have to be dealt with.

Metal extraction

Once the metal ores are mined they are then processed to give the pure metal.  In the example of copper extraction:

Impurities form the leaching process and the waste products could contain trace toxic metals e.g. mercury which could wash into water supplies.  Sulfur in the ore will react to form sulfur dioxide, this will dissolve in rain clouds forming acid rain (sulfuric acid).  This acid rain can fall on trees and plants damaging leaves and in extreme cases killing plants, or into lakes killing aquatic life such as fish.

The images below show Port Talbot Steel works during the day and at night.  Greenhouse gases being emitted, excess fuel being burnt at night producing carbon dioxide.

Each step in the process of extracting a metal like copper or processing iron into steel requires energy – either electricity or heat.  This essentially comes from burning fossil fuels.  Burning fossil fuels releases carbon dioxide into the atmosphere.  This gas is a greenhouse gas and contributes to global warming.  This can cause the Earth to become warmer which in turn effects many ecosystems:

• Polar ice caps melt, causing sea levels to rise, low lying coastal lands could become flooded.
• Areas suffering from drought will increase leading to famine.
• Some areas will experience greater rainfall leading to flooding.

These are just a few examples where human activities have impacted the Earth and its environment.