Climate Change

Question 1

Evidence for Climate Change

Answer 1

Oxygen trapped in layers of ocean sediments, and water molecules in Antarctic snow, can be analysed to calculate the temperature in the past. These measurements indicate a clear warming trend, with most of the increase since the mid-70’s.

Rising sea level
 Glacier and ice cap melting adds fresh water.
 Thermal expansion – warm ocean waters expand in volume.
 Low-lying islands such as the Maldives, and coastal regions in Bangladesh, India and Vietnam, in danger of flooding.

Seasonal changes
Tree flowering and bird migration is advancing, the bird nesting is earlier than in the 1970’s.

Question 2

Sources of Evidence for Climate Change

Answer 2

Thermometers = for the UK there have been accurate records since 1910 proving the trend of the average temperature rising

Ice cores = drilling into ice in areas like Greenland. Tiny bubbles of trapped atmosphere show levels of CO2 and other greenhouse gases. Used to help create computer models - predictions of the future

Tree Rings - Experts can infer something about the climate through the space between the rings

Question 3

What are the Natural Causes for Climate Change : Orbital Changes

Answer 3

Orbital changes
Eccentricity – every 100 000 years or so the orbit changes from almost circular to mildly elliptical (oval) and back again.
Axial tilt – every 41 000 years the tilt of the earth’s axis moves back and forth between 21.5o and 24.5o.
Precession (or wobble like a spinning top) – over a period of around 26 000 years the axis wobbles from one extreme to another.

Question 4

Natural Causes of Climate change: Solar Output

Answer 4

Solar output
The surface of the sun has dark patches called sunspots which mark the short-term regions of reduced surface temp. they are usually accompanied by explosive, high-energy solar flares increasing heat output.
Over a period of 11 years, sunspots increase from a minimum, to a maximum and back again.

Question 5

Natural Causes of Climate Change : Volcanic activity

Answer 5

Volcanic activity
Volcanic ash can block out the sun, reducing temps on the Earth. This is a short-term impact.
Sulphur dioxide is also blasted out which converts to sulphuric acid, and acts like mirrors to reflect solar radiation back into space. This longer-term impact also reduces temperatures.

Question 6

Human Causes of Climate Change

Answer 6

the human impact on the greenhouse effect – Normally greenhouse gasses trap heat that would otherwise escape into space however we have enhanced this effect by releasing more and more greenhouse gasses though our industries and daily lives.

 Carbon dioxide – accounts for and estimated 60% of the enhanced greenhouse effect. The global concentration has increased by 30% since 1850.

Burning fossil fuels in industry
Car exhausts
Deforestation

 Methane – very effective in absorbing heat, accounts for 20% of the enhanced effect.

Rice farming
Farm livestock
Burning biomass for energy
Decaying organic matter in landfill sited and compost tips.

 Nitrous oxides – very small concentrations in the atmosphere are up to 300 times more effective in capturing heat than carbon dioxide.

Car exhausts
Agricultural fertilizers
Sewage treatment
Power stations producing electricity

Question 7

Define Mitigation

Answer 7

the action of reducing the severity, seriousness of something.

Question 8

Define Adaption

Answer 8

the action or process of adapting or being adapted, changing.

Question 9

Alternative energy sources

Answer 9

such as nuclear, hydroelectric, solar, wind and tidal. They don’t emit large quantities and some are renewable so they won’t run out like other finite sources.

Question 10

Managing Impact : Carbon Capture

Answer 10

(CCS) uses tech to capture carbon dioxide from the use of fossil fuels. It captures 90% of the carbon dioxide, once captured it is compressed and transported by pipeline to an injection well where it will be injected as a liquid to be stored in suitable geological reservoirs.

Question 11

Managing Impact: Planting Trees

Answer 11

– trees act as carbon sinks removing carbon dioxide, through photosynthesis.

Question 12

Managing Impact: International Agreement

Answer 12

they insure that everyone has to take part such as the Paris agreement in 2015 – 195 countries adopted the first ever universal and legally binding global climate deal)

Question 13

Managing Impact: Managing water suppply

Answer 13

as there are more severe and frequent droughts or floods this is important. unreliable rainfall and periods of water shortage require management.

This includes;

• Introducing drought-resistant crops
• New irrigation systems
• Educating farmers in water harvesting techniques
• Using shade trees to protect seedlings from the strong sun
• New cropping patterns by changing the cropping dates.

Question 14

Managing Impact:Reducing risk from rising sea levels

Answer 14

average sea levels have risen 20cm since 1900. By 2100 sea levels are expected to rise another 26-82cm. This will flood important agricultural land in countries such as Bangladesh, India and Vietnam.

These are some methods which can be implemented in the Maldives;

• Constructing sea walls – a 3m wall is being constructed around the capital.
• Building houses raised on stilts
• Construction of artificial islands
• Relocation (ultimately to India or Sri Lanka)
• Restoration of the mangrove forests – their tangled roots trap sediment and offer protection from storm waves.