Economic activities such as the ones mentioned above generate jobs and incomes for people and countries. Global trade has enabled people to access resources and foods from all over the globe and raised standards of living. These industries all impact upon the environment in many negative ways but they bring substantial economic benefits to the human populations that work in them. With rising global populations it is inevitable that agricultural practices are going to impact on increasing areas of land.
Describe how these developments may also pose threats to the environment when natural ecosystems are interfered with including: soil erosion, global warming, and pollution (air, water, noise and visual).
Human activities have had a big impact on the rate of soil erosion around the world. Farming methods often leave bare soil exposed to the wind and rain after ploughing and sowing seeds. Deforestation has been a major cause of soil erosion as trees intercept rainfall, soak up substantial quantities of water from the soil and the roots help hold soil in place. Mountainous areas such as the Himalayas that have suffered deforestation experience severe erosion of slopes as rain washes the soil away. Tropical regions such as the Amazon river basin also suffer soil erosion once the trees are removed.
Managing Soil Erosion
There are many techniques that can be used to reduce rates of soil erosion.
Contour ploughing: ploughing across slopes following the contours rather than up and down them reduces erosion as it creates ridges that stop water gathering any momentum.
Terracing: creating terraces on steep slopes again reduces the flow of any surface runoff and allows more to infiltrate into the soil.
Hedges/walls: barriers such as hedges significantly reduce erosion by wind.
Crop rotation: rotation of crops gives soils chance to replenish different nutrients and remain more fertile.
Afforestation: planting trees to increase interception, water uptake by roots and stabilisation of soils by root structures.
Human activities have serious impacts on water quality. Agricultural chemicals used on crops leach into rivers and groundwater supplies. Fertilisers have led to eutrophication in many lakes and rivers as the fertilisers cause excessive growth in river plants and algae.
The oil industry has had many high-profile oil spills in the oceans which have caused immense damage. The BP deepwater Horizon oil spill, 2011, Gulf of Mexico was the most recent example and gushed oil for months before the leak was stopped.
One of the major concerns currently is the level of plastic pollution in the oceans, most of which has been washed into the sea from rivers.
Industry and transport release substantial quantities of damaging gases into the atmosphere.
Scientists generally agree that humans are contributing to the warming of the climate by releasing greenhouse gases into the atmosphere. The greenhouse gases play an important part in keeping our atmosphere warm (without them we would not survive) but at present the increasing quantities are starting to cause rapid warming of the atmosphere.
Carbon dioxide is the one that is referred to most often and is released largely through the burning of fossil fuels in industry, electricity generation and transport. Deforestation around the globe is reducing natures ability to remove carbon dioxide from the atmosphere through photosynthesis, in addition burning the wood releases more carbon dioxide.
Methane is also a greenhouse gas released as waste gas from livestock, decomposing vegetation (large dams release methane) and potentially from large areas of semi-frozen tundra as it warms up and thaws.
CFCs are very potent (strong) greenhouse gases but their use has been significantly reduced over the last 20 years in response to damage to the ozone layer.
Effects of climate change
- Melting of ocean & mountain glaciers leading to more water in the oceans.
- As the oceans warm they expand, this thermal expansion is causing sea level rise.
- Warmer sea temperatures leading to more tropical storms & stronger tropical storms.
- Changing weather patterns in many regions of the world.
- Warming seas are damaging coral reefs which are a very important part of marine ecosystems.
Sulphur dioxide and nitrogen oxides released from transport and industry mix with water vapour and return to earth as acid rain (nitric and sulphuric acid). Rain is usually slightly acidic but these gases can significantly lower the PH level and cause environmental damage. Vegetation suffers (possible death) due to roots absorbing the rainwater, lakes become more acidic which impacts on fish and aquatic plants.
Acid rain is often a problem that affects places far from the source of the pollution. Winds blow the pollution large distances before it falls as rain which often makes it an international problem. Scandinavian countries and Northern Germany have suffered extensive environmental damage to pine forests and lakes from acid rain that many claim originated in the UK.
Countless places are at risk from environmental problems. In general, it is the poorer countries that have limited resources at their disposal to protect against the changes or deal with the consequences. Richer countries have the financial ability to build extensive infrastructure to combat environmental change. Richer countries are also better able to develop alternatives to polluting substances which are often more expensive. More efficient cars, buses & lorries are good examples, LEDCs tend to have older, heavily polluting vehicles which cause substantial air pollution and health effects.