Human Causes of Climate Change

What is the greenhouse effect?

1. Short wave radiation (UV) incoming from the Sun

2. UV rays absorbed by Earth

3. Energy is re-emitted  as long wave (infrared) radiation

4. Long wave radiation (infrared) is absorbed + re-emitted or reflected by greenhouse gases in the atmosphere

5. Some radiation escapes the atmosphere into the space.

What is the average temperature of Earth without the natural greenhouse effect?

18 degrees celcius

What is the average temperature of Earth with the natural greenhouse effect?

15 degrees celcius

What is the enhanced greenhouse effect?

Humans enhance the effect by adding more greenhouse gases to the atmosphere.

Percentages of humans sources of all greenhouse gases

• Agriculture - 13%

• Biomass burning - 10%

• Fossil fuel retrieval - 11%

• Industry - 17%

• Power stations - 21%

• Residential use - 10%

• Transportation - 14%

• Waste disposal - 4%

How does industry change greenhouse gas emissions?

As levels of disposable income rise, increased demand for goods has arisen. This leads to industrial growth and the need for more energy meaning more fossil fuel burned.

How does transport change greenhouse gas emissions?

Almost all types of transport rely on burning fossil fuels in some way. Transport has developed hugely with flights becoming more common and cars becoming more affordable - meaning more fossil fuels are burned.

How does energy change greenhouse gas emissions?

The demand of electricity is growing because of increasing population and new technologies.

How does farming change greenhouse gas emissions?

As led to a higher demand for food production. Mechanisation on farm means more fuels used to produce this food.

What should we consider when thinking about the consequences of climate change?

Stakeholders - different perspectives.

What are possible consequences of climate change?

• Sea levels rise

• Increased temperatures

• Extreme weather events

How is sea levels rising a consequence of climate change

• Maldives submerged

• 23% of global population live < 100km of coast

• Bangladesh loses 50% of the best farmland - food supply issues

• Salt water contaminates farmland and groundwater

  • New sea defences need to be constructed as they are destroyed - huge costs

How are extreme weather events consequences of climate change

• Longer + more frequent droughts

• Rise in tropical cyclones

• High level of destruction and death

  • Heavy snowfall

How are increased temperatures consequences of climate change

• Habitat change - reduce in biodiversity

• Important rivers dry up - limits water supply

• Sea levels rise and ice sheets melt

• Impacts food production (where different crops can be grown)

• Spread of pests and diseases (cold winters limit pests + diseases for spreading)