Changes in the Carbon Cycle Flashcards

1
Q

What happened during the quaternary geological period?

A

Global climates fluctuated considerably between warm (interglacial) periodsand cold periods (glacial)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

Higher temperatures are associated with…

A

Higher carbon dioxide levels in the air

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

An increase in the level of carbon dioxide in the air leads to..

A

Enhanced global warming and subsequent temperature increase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

Lower levels of carbon dioxide…

A

Reduces the effectiveness of the greenhouse effect

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is the impact of cold conditions on carbon stores and transfers?

A
  • chemical WEATHERING processes would have been more ACTIVE as cold water can hold more CO2
  • DECOMPOSERS would have been LESS active, so carbon transfer to soils would be reduced
  • SOIL would be FROZEN OVER vast areas of land. This would have stopped transfers of carbon
  • less water would FLOW into oceans because it would be LOCKED UP on the land, therefore less BUILDUP of SEDIMENTS on the ocean floor
  • FOREST COVERAGE would be different (geographically and its total area). This would affect the distribution of processes such as photosynthesis and respiration
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the impacts of warmer temperatures on carbon stores and transfers?

A

Carbon stored in permafrost (along with other gases eg methane) are now being released into the atmosphere when it melts which further enhances the greenhouse effect, leading to increased warming.

This positive feedback system leads to a further destabilisation of the system.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

Where is the melting of permafrost prevalent?

A

In tundra regions such as Russia and Siberia

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

How do wildfires affect the carbon cycle?

A

Even though forests only cover a small surface of the Earth, wildfires (started by lightening, or deliberately by people) turn forests from being a carbon sink into a carbon source because combustion returns huge quantities of carbon back into the atmosphere.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

Example of a wildfire?

A

In 2013, the Indonesian wildfires burned out of control for months and their smoke spread to South-East Asia.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

How does volcanic activity affect the carbon cycle?

A

Eruptions return to the atmosphere that has been trapped for millions of years in rocks stored deep within the Earth’s crust.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

When were volcanoes most active?

A

In the polaeozoic period

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

How much carbon dioxide do volcanoes emit in comparison to human activity per year?

A

Volcanoes = between 130 and 380million tonnes of CO2

Humans = 30 billion tonnes of CO2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How does lava affect the carbon cycle?

A

Lava contains silicates which slowly weather. This converts CO2 in the air into carbonates in solution. In this way, carbon is absorbed very slowly from the atmosphere.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What do scientists believe the trigger is for the delay between temperature and carbon dioxide levels in the Vostock ice core?

A

Orbital change - the Milancovitch cycles.

These regular cycles of orbital eccentricity cause slight variations in the amount of suns radiation that warms up the Earth.

So, as temperatures start to rise at the end of a glacial period (triggered by orbital change), there is a surge of carbon dioxide released into the atmosphere by the warming of the oceans and unlocking of land surface that had previously been frozen.

This surge of CO2 enhances the greenhouse effect, amplifying the warming trend.

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Interglacial periods?

A

Warm periods

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

Glacial periods?

A

Cold periods

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is the IPCC?

A

Intergovernmental Panel on Climate Change

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What does anthropogenic mean?

A

Human caused

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

According to the IPCC, what % of anthropogenic carbon release comes from the combustion of fossil fuels?

A

90%

20
Q

Since the 1960s, global concentrations of carbon dioxide have increased dramatically from … ppm to … ppm

A

From 320 ppm to 400 ppm

21
Q

What are fossil fuels?

A

Natural sources of energy formed from the remains of living organisms, primarily plants. They are extremely important long term stores of carbon, comprising carbon locked away within the remains of organic matter.

22
Q

Today, where is most of the world’s oil and gas extracted from?

A

Rocks that are 70 - 100 million years old

23
Q

What happens when fossil fuels are burnt to generate electricity and power?

A

The stored carbon is released, primarily as carbon dioxide into the atmosphere, accelerating the cycle of this carbon.

Once in the atmosphere, it enhances the natural greenhouse effect, increasing global temperatures - “global warming”.

24
Q

Since the late 1950s, how has carbon dioxide in the atmosphere has been measured?

A

By the Hawaiian Volcanic Observatory

25
Q

How much is land use responsible for global carbon release?

A

10%.

26
Q

How do livestock increase methane production?

A

Livestock (especially cattle), RUMINATE, which produces methane as a byproduct.

27
Q

Why is there a desirability or move away from such high dependence on meat and dairy products?

A

Because cattle alone release 20% of total methane emission sin the USA.

28
Q

What is the link between methane and rice?

A

Methane is produced from the cultivation of rice - up to 20% of global methane production.

29
Q

What has research in Asia and North America found regarding rice yields?

A

Rice yields have increased by 25% due to increased levels of carbon dioxide levels in the air. (But in turn has lead to a 40% increase in methane emissions).

30
Q

Why will the methane emissions from rice continue?

A

Because rice is the primary food source for 50% of the world’s population.

31
Q

Define deforestation.

A

The removal of trees, either by burning or felling, for building, ranching, mining or the growth of commercial crops such as palm oil or soya.

32
Q

Where is deforestation most common?

A

It is widespread across the world, but is particularly concentrated in tropical regions.

33
Q

How does deforestation affect the carbon cycle?

A

In a natural system, when a tree dies it decomposes very slowly and releases carbon over along period of time. During that time, new vegetation begins to grow and quickly compensates for the carbon released by the dead tree - so the system is carbon neutral.

However, when deforestation by burning occurs, carbon is immediately released into the atmosphere (and if the land is used for a different purpose, e.g. grassland for cattle ranching, then the future absorption of CO2 will be reduced.

(Now a source - not a sink).

34
Q

Globally, how much of the Earth’s surface is covered by urban areas?

A

2%

35
Q

Urban areas account for how much of global anthropogenic carbon emissions?

A

97%

36
Q

How does cement affect carbon cycles?

A

Carbon dioxide is a byproduct

37
Q

Why do volcanoes only have a small scale impact on climate?

A

Because when they erupt, they release carbon dioxide into the atmosphere along with ash and other gases. This absorbs more incoming radiation from the sun and can lead to a volcanic winter - a reduction in global temperatures.

38
Q

Why may increased ocean temperatures cause more clouds to form?

A

Because these warmer temperatures along with more sunshine attracts marine phytoplankton (which release DMS) which promote condensation - and therefore cloud formation - over the ocean.

39
Q

What is ocean acidification?

A

The ongoing decrease in ocean pH caused by human CO2 emissions (e.g. the burning of fossil fuels).

40
Q

Explain the effect of ocean acidification for coral reefs.

A

Ocean acidification may decrease the reef growth by reducing calification rates, and this affects the skeletal growth of reef building organisms.

41
Q

Explain how in the past decade the global carbon cycle has been negatively affected.

A
  • wildfires burn large areas of peatland which release the previously stored carbon dioxide into the atmosphere. This release of CO2 leads to global warming.
  • also when dry peat burns down to the water table, tree roots are exposed meaning the forest vegetation becomes unstable, and trees fall with large areas of forest being lost.
  • thirdly, the smoke from the fire reduces light intensity that reaches pleats near the areas of the forest fires, as sunlight is blocked out. This therefore reduces photosynthesis and subsequently less CO2 is converted into O - so there is more carbon in the atmosphere.
42
Q

What is a net carbon sink?

A

When more carbon enters a store than leaves it

43
Q

What is a net carbon source?

A

When more carbon leaves a store than enters it.

44
Q

What is the geological component of the carbon cycle?

A

Where it interacts with the rock cycle in the processes of weathering, burial, subduction and volcanic eruptions.

45
Q

How is carbon dioxide removed from the atmosphere?

A

By dissolving it in water and forming carbonic acid

46
Q

Carbon dioxide dissolves in water to form carbonic acid. What happens when this acidic water reaches the surface of the Earth as rain?

A

When it reaches the surface, it reacts with minerals at the Earth’s surface - slowly dissolving them into their component ions through chemical weathering. These component ions are carried in surface waters (eg streams and rivers) where they settle our as minerals like calcite - a form of calcium carbonate.