Hazardous Earth

Question 1

What are some natural causes of climate change?

Answer 1

Eccentricity/ Obliquity/ Precession
Asteroid activity
Volcanic Activity
Sun spots

Question 2

What is eccentricity and how does it cause climate change?

Answer 2

Changes in the Earth’s orbit, which deduct how far away it is from the Sun.
Less elliptical = cooler periods
More elliptical = warmer periods
1 cycle takes 100,000 years.

Question 3

How does volcanic activity cause climate change?

Answer 3

They cause large amounts of sulphur dioxide and gas to be released. Sulphur dioxide reacts with other substances to produce sulphur particulates - which reflect nearly all kinds of solar radiation, causing global cooling
It can also have the opposite effect - large amounts of greenhouse gasses (such as co2) are also released, which contribute to the greenhouse effect, causing global warming.

Question 4

What are sun spots and how do they cause climate change?

Answer 4

Sun spot cycle - an 11 year cycle where the amount of sun spots on the Sun’s surface varies. When there is less sun spots, there is a lower solar output.
There is identified relationship between the Earth’s climate and the amount of sunspot activity present on the Sun - solar output variations do affect the temperature on Earth.

Question 5

What is Obliquity and how does it cause climate change?

Answer 5

Obliquity - the tilt of the Earth’s axis.
It affects the contrast between summer and winter seasons.
To change between 21.5° to 24.5° takes ~41,000 years.

Question 6

What is Precession and how does it cause climate change?

Answer 6

Precession - describes the wobble of the Earth’s axis.
It affects the length of days, which can affect the amount of sunlight received.
A full cycle can take 20,000 years.

Question 7

How can asteroid collisions cause climate change?

Answer 7

If the asteroid is large enough, millions of tonnes of ash and debris would be ejected into the atmosphere when it impacts the Earth. This could block out the sun and cause global cooling.

Question 8

What are some human causes of climate change?

Answer 8

Energy use
Transport
Industry
Farming
Deforestation

Question 9

How does our energy use contribute to climate change?

Answer 9

Burning fossil fuels releases a greenhouse gas, CO2 into the atmosphere. It enhances the greenhouse effect.

Question 10

How does industry contribute to climate change?

Answer 10

Cement production is one of the biggest industrial emitters of greenhouse gasses - industry can release greenhouse gasses which contribute more to the greenhouse effect than CO2, such as fluorinated gasses and nitrous oxides

Question 11

How does transport contribute to climate change?

Answer 11

Most fuel is petroleum based, meaning using vehicles will often release CO2

Question 12

How does farming contribute to climate change?

Answer 12

Farming livestock produces methane gas, as do cultivation methods of crops such as rice.

Question 13

How does deforestation contribute to climate change?

Answer 13

Trees take in CO2 for photosynthesis, meaning they decrease the CO2 conc. in the atmosphere and weaken the greenhouse effect. A lack of trees means CO2 stays in the atmosphere and enhances the greenhouse effect.

Question 14

What is some evidence of human causes of climate change?

Answer 14

Rising sea levels
Glacial retreat
Melting ice sheets
Increased level of extreme weather

Question 15

How do rising sea levels evidence climate change?

Answer 15

By the 20th century, global sea levels rose by about 14cm - they are rising faster now than 50 years ago. It has occurred due to melting ice sheets flowing into the oceans and causing it to rise.
(Water also expands as it gets warmer (thermal expansion), so the whole sea is expanding and rising.)

Question 16

How is glacial retreat evidence of climate change?

Answer 16

Long term trends show that glaciers are retreating at a historically unprecedented rate. Some glaciers are projected to completely melt by 2035, the majority are shrinking and thinning.

Question 17

How are increased extreme weather events evidence of climate change?

Answer 17

Different scientific studies have used computer modelling to make links between the contribution of human activity to rising global temps and the increased likelihood of extreme weather events occurring.
Nine out of the 10 hottest years have been recorded in the 21st century. Precipitation is also becoming more intense, posing a flooding risk. Tropical storms and forest fires are also becoming more intense.

Question 18

What is some evidence of natural causes of climate change?

Answer 18

Ice cores
Tree rings

Question 19

How do ice cores evidence climate change?

Answer 19

They can provide information about what the climate was like hundreds of thousands of years ago. The composition of water can be analysed to calculate what the temperature of the atmosphere was when the water fell as snow. Air bubbles trapped in the ice can also be analysed for levels of CO2 and other gasses

Question 20

How do tree rings evidence climate change?

Answer 20

Tree rings are wider in warm, wet years and narrow in cold, dry years. By compiling data, scientists can gather evidence about how the climate has changed over hundreds of years.

Question 21

What are some effects of climate change on people?

Answer 21

More health issues - famine, dehydration, hygiene related diseases.
Risk to water supplies and more droughts.
Poor food security - crops fail due to climate change.
Damage to infrastructure and property.
Displaced populations and climate migrants.
Coastal flooding.

Question 22

What are some effects of climate change on the environment?

Answer 22

Damage to marine and terrestrial ecosystems.
Warming oceans - melting ice sheets, glaciers and sea ice - rising sea levels.
Warmer temperatures.
More areas susceptible to diseases.
Changes in ocean currents and weather patterns.
Extreme weather, e.g. droughts, wildfires, tropical storms , wildfires.

Question 23

Why can’t we predict climate change? (refer to book)

Answer 23

The atmosphere and oceans are extremely complex and respond to changes in unexpected ways.
We cannot be certain about the extent of Arctic and Antarctic ice sheet loss.
There is uncertainty about changes in cloud cover and its effect on global warming.
The rate of future greenhouse gas emissions is difficult to predict.

Question 24

What are the global temperature predictions for the future?

Answer 24

The surface temperatures are expected to rise by the end of the century - the amount projected is between 1.1°C to 6.4°C, but this is dependent on the location.

Question 25

What are the sea level rise predictions for the future?

Answer 25

It is estimated to rise, the range predicted is 30cm to 2.5m. It is expected to occur due to melting ice sheets and warmer temperatures, which cause the sea to expand (thermal expansion).

Question 26

What are some physical uncertainties about climate change? (refer to PMT)

Answer 26

There is uncertainty about how natural processes may enhance warming e.g. forest fires.
Some sources of water that contribute to sea level rise are variable, so they are difficult to account for.
There is uncertainty about how weather phenomena may affect temperatures.
Cold meltwater from glaciers and ice caps reduces the effect of thermal expansion, so less sea level rise.

Question 27

What are some human uncertainties about climate change? (refer to PMT)

Answer 27

We don’t know how big the population will be in future, so uncertainty about food demands.
Lifestyles may change as people become more aware of climate change.
Future technologies may help cut emissions, e.g. carbon capture.
There is uncertainty about how much green energy we will use globally.