Lesson 11- How is climate change influencing the carbon cycle and can we mitigate it?

Question 1

Types of greenhouse gas effect?

Answer 1

• The greenhouse gas effect
• The ENHANCED greenhouse gas effect

Question 2

Types of greenhouse gas effect-The greenhouse gas effect

Answer 2

• Electromagnetic radiation passes through the Earth’s atmosphere.
• The Earth absorbs most of the radiation and warms up.
• The Earth radiates energy as infrared radiation.
• Some of the infrared radiation goes into space.
• Some of the infrared radiation is absorbed by greenhouse gases in the atmosphere.
• The lower atmosphere warms up.

Question 3

Types of greenhouse gas effect-The ENHANCED greenhouse gas effect

Answer 3

• The Enhanced Greenhouse Effect is causing global warming as high levels of greenhouse gasesfrom humans, trapping radiation from the sun, causing global warming.
• The key point with this is that more incoming solar radiation is absorbed than let out into space this is known as radiative forcing
• 65% of radiative forcing is caused by CO2

Question 4

How does the enhanced greenhouse effect create positive feedback?

Answer 4

1)Humans increase CO2 in atmosphere by burning fossil fuels
2)This causes increased temperatures as the greenhouse effect is enhanced
3)This causes higher evaporation as temperatures are higher more of the year
4)This means there is more water vapor in the atmosphere acting as a greenhouse gas (50% of the greenhouse effect is water vapour) causing further warming

Question 5

How significant is the impact of water vapour on global warming?

Answer 5

• Although Co2 contributes less to the overall greenhouse effect than water vapour, scientists have found that it is the Co2 that controls the temperature.
• This rise in temperature is not all the warming that we will see based on current Co2 concentrations. There is a lag time between increased Co2 and increased warming.
• The temperature will increase by a further 0.6ºC because of the Co2 already in the atmosphere.

Question 6

What are all the causes of the enhanced greenhouse gas effect?

Answer 6

• Land Use Changes
• Fertilisers
• Deforestation
• Urbanisation

Question 7

Causes of enhanced greenhouse effect-Land Use Changes

Answer 7

• 10% of carbon released into the atmosphere by humans comes from agriculture impacting the soil and the biosphere.

For example - Farming Practices:

• In the Amazon, 70% of deforestation is for cattle ranching.
• Cattle produce methane, further contributing to global warming.
• Methane is more powerful than CO2 as a greenhouse gas so increases the enhanced greenhouse effect more rapidly.

Question 8

Causes of enhanced greenhouse gas effect- Fertilisers

Answer 8

• 5% of global human CO2 emissions
• Farming using fertiliser causes microbes in the soil to break down the nutrients in the crops, transferring carbon from the biosphere to the atmosphere, because it produces nitrous oxide which has a warming effect 265 times greater than CO2.
• Intensive farming uses lots of fertilisers, this causes the soil to get more acidic, this means that the amount of living/organic stuff in the soil is reduced. It is the living stuff that has the carbon in it so it decreases the amount of carbon stored in the soil.

Question 9

Causes of enhanced greenhouse gas effect- Deforestation

Answer 9

• In total, deforestation is 20% of all global greenhouse emissions.
• This is due to carbon being lost from the biosphere and transferred into the atmosphere as trees are cut down.
• The main impact of deforestation is when the land is used for other purposes such as farming, which then reduces carbon sequestration and land becomes a carbon source rather than a carbon sink.

Question 10

Causes of enhanced greenhouse gas effect- Urbanisation

Answer 10

• Replacing countryside with buildings and other similar infrastructure.
• Affects carbon byreplacing vegetation and covering soils.
• Urban areas are 2% of the world’s land mass, but account for 97% of all human caused global CO₂ emissions.
• Cement is an important building material, but releases carbon dioxide during production, contributing 7% to global carbon dioxide emissions each year, so sustainable options for recycling concrete are being developed.