What are the main environmental risks?
Caused by humans
- Soil Erosion
- Desertification
- Global Warming
- Pollution (including water, air, noise and visual)
Def. Radiation
The energy that is radiated or transmitted in the form of rays or waves or particles
Def. Solar radiation
Short wave radiation from the sun
Def. Longwave radiation
Radiation emitted from Earth is called longwave radiation
What are the solutions to mitigate global warming?
- Renewable energy
- Reduce, reuse, recycle
- Afforestation
- Carbon sequestration (capturing carbon dioxide before it is released into the atmosphere)
- International agreements (Paris Agreement - countries have agreed they wish to keep global warming to less than 2 degrees temperature rise through reducing emissions)
- Electric cars
What are the solutions to adapt to global warming?
- Build more sea defences
- Disease treatment (many diseases will become more prevalent so we could research new cures and treatments to reduce their impacts)
- Desalination (removing salt from salt water to create water which is fit for human consumption)
- Resettlement
- Air conditioning
- Xeriscaping
Describe the process of reduce, reuse and recycle
- Reduce: This refers to using less of a product e.g., less packaging, less energy.
- Reuse: This means using a product more than once. This might be returning it to a manufacturer e.g., coke bottles or selling/passing onto another consumer e.g., charity shops
- Recycle: The re-processing of industrial and household waste so that materials can be reused. Currently materials like paper, card, plastics, glass and some metals are recycled.
Def. Soil Degredation
Soil degradation is the decline in quantity and quality of soil
Def. Desertification
The process by which land becomes degraded to an unusable state
What are the main human causes of desertification?
- Overgrazing: Allowing too much livestock to graze on a piece of land which means all the vegetation is eaten making the ground susceptible to wind and water erosion.
- Overcultivation: If you farm land to intensively and don’t have fallow (periods of not growing anything) periods then all the nutrients in the soil get used.
- Deforestation: Cutting down trees which not only means the land will be receiving less nutrients, but it also means it is more vulnerable to erosion because there is no interception and less stability because the root systems have been removed.
- Overpopulation: As the world population continues to grow (now nearly 7 billion) the demand for agricultural products (crops and meat) is increasing causing more land to be deforested, over-cultivated and overgrazed.
- Fertiliser and Pesticide Use: By using fertilisers and pesticides you can artificially increase yields of crops. However, the process is unnatural and prolonged periods of use can all naturally produced nutrients to be used and local water sources to become polluted reducing the ability of land to cultivate crops and therefore making it vulnerable to chemical degradation as well as wind and water erosion.
- Unsustainable Water Use (aquifer depletion, unsustainable irrigation): If aquifers or rivers are used unsustainably then areas can become increasingly arid as water resources are used up.
What are the main physical causes of desertification?
- Rising Temperatures: As global temperatures increase it is becoming increasingly hard for vegetation to grow thus reducing vegetation cover and increasing the risk of wind and water erosion.
- Falling Rainfall: As the amount of rainfall reduces in some areas like the Sahel, then it is increasingly hard for vegetation to grow again making the ground more vulnerable to wind and water erosion.
- Flash floods: Intense periods of rainfall can also cause erosion of topsoil which leads to land degradation.
- Wind: If a region is particularly windy then the amount of wind erosion is likely to increase.
What are the strategies to reduce desertification?
- Planting more trees - their roots hold the soil together and reduce soil erosion from wind and rain
- Improving the quality of soil - Done by reducing grazing, reducing the cultivation of animals and replacing this with crops instead, use animal manure to fertilise soil e.g. Zai pits
- Water management - water can be stored in times of water surplus to be released in times of water deficitvia e.g. earth dams
- Stone bunds - Rows of stones places around contour lines to prevent the flow of water away from crops, to keep water in soil
- Drip irrigation - Slow dropping of water onto the grounds through small holes in hoses on the soil, minimising water loss and maximising efficiency
What is air pollution and what contributes to it?
Air pollution is the contamination of air by smoke and harmful gases, mainly oxides of carbon, sulfur, and nitrogen. Some examples of air pollution include:
- Exhaust fumes from vehicles
- The burning of fossil fuels, such as coal, oil, or gas
- Harmful off-gassing from things such as paint, plastic production, and so on
- Radiation spills or nuclear accidents
What is water pollutiion and what contributes to it?
Water pollution is the contamination of any body of water (lakes, groundwater, oceans, etc). Some examples of water pollution:
- Raw sewage running into lake or streams
- Industrial waste spills contaminating groundwater
- Radiation spills or nuclear accidents
- Illegal dumping of substances or items within bodies of water
- Biological contamination, such as bacteria growth
- Farm runoff into nearby bodies of water
Describe the impacts of global warming on the natural environment
Be specific
- One problem is ocean acidification. Our oceans are a carbon sink, absorbing about 30% of the carbon dioxide that is emitted into the atmosphere. However, as carbon dioxide increases in the atmosphere our oceans are absorbing more and more carbon dioxide and this leads to ocean acidification. Ocean acidification harms marine species, for example coral reefs, as it affects their ability to form their exoskeletons from calcium carbonate.
- Global warming is also affecting coral reefs in other ways. For example, increased sea temperatures leads to coral stress, when this occurs they evict the algae that they feed on. This leads to coral bleaching and can result in coral death. Thermal stress can affect corals over a huge geographic area like the entire northern Great Barrier Reef or archipelagos like the Maldives.
- Another environmental impact of global warming is the melting of sea ice. Sea ice is melting most rapidly in the Arctic, where we are losing almost 13% per decade. One Arctic species that is under threat due to global warming is the polar bear. They spend most of their lives around water and ice and so they’re at particular risk from global warming as the Arctic ice they depend on is melting.
