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IB HL Biology > 4.4 Climate change > Flashcards

4.4 Climate change Flashcards

1
Q

What is the intensified natural greenhouse effect?

A

The natural greenhouse effect that is occurring at an unnatural rate due to human activities, such as combustion of fossil fuels.

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2
Q

Which two greenhouse gases have the greatest impact on the greenhouse effect?

A

Carbon dioxide and water vapor.

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3
Q

Give examples of greenhouse gases that have less of an impact than CO2 and water vapor

A

Methane and nitrogen oxides

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4
Q

Together, the greenhouse gases act like an ___

A

Insulating layer

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5
Q

What type of system is the Earth and what does this mean?

A

-Earth is a closed system; not much escapes its gravity and atmosphere.

-That means that, although the amount of carbon dioxide and water on this planet is finite, the state of the molecules can change.

-Both carbon dioxide and water vapour are recycled.

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6
Q

What cycle is carbon dioxide part of?

A

The carbon cycle.

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7
Q

What cycle is water part of?

A

The water cycle

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8
Q

How is carbon dioxide released and stored?

A

-It is released by heterotrophs and autotrophs when they respire, and also through the combustion of biomass or fossil fuels.

-There are two ways in which carbon dioxide is taken out of the atmosphere: photosynthesis and by dissolving in oceans and lakes.

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9
Q

How is water vapor released and stored?

A

-It is the gaseous form of water, formed through evaporation from bodies of water.

-Natural precipitation, such as rain, hail, and snow, return water to the Earth as part of the water cycle.

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10
Q

Describe CO2 and water vapor as greenhouse gases

A

-Both carbon dioxide and water vapor absorb longwave or infrared radiation and are considered the main greenhouse gases.

-Both gases are very abundant in the atmosphere, both naturally and due to human activity.

-The more greenhouse gases that are in the atmosphere, the stronger the effect of the greenhouse effect and the warmer the Earth becomes.

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11
Q

Define greenhouse gases

A

Gases found in the atmosphere such as water vapour, carbon dioxide, methane and nitrous oxides, that contribute to the greenhouse effect.

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12
Q

What is water vapor?

A

-Water found in the atmosphere in a gaseous form.

-It is the most abundant greenhouse gas.

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13
Q

What is carbon dioxide?

A

-A gas found in the atmosphere that is a main greenhouse gas.

-Carbon dioxide enters the atmosphere by respiration and decomposition as well as burning of biomass and combustion of fossil fuels.

-It is taken out of the atmosphere by the process of photosynthesis and absorption by water.

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14
Q

Diagram showing the percentage contribution of various gases to the greenhouse effect

A
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15
Q

What does a gas need to do to contribute to the greenhouse effect?

A

It needs to be able to absorb longer wavelength radiation.

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16
Q

How are methane and nitrous oxides different from CO2 and water vapor?

A

-Methane (CH 4 ) and nitrous oxides (N 2 O and NO) are able to absorb longer wavelengths of infrared radiation.

-They contribute to the greenhouse effect, but not as much as carbon dioxide and water vapor.

-However, it should be noted that despite being released in smaller amounts, methane traps 20 times more heat than the same amount of carbon dioxide; that is, methane causes faster warming of the planet.

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17
Q

How is methane emitted?

A

-Methane occurs naturally.

-It escapes from melting ice and tundra in the Arctic, it escapes from landfills and marshes, and it is produced by cattle.

-Sometimes it is emitted during the extraction of fossil fuels.

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18
Q

How are nitrous oxides emitted?

A

-By car engines and can be produced by certain bacteria.

-Small quantities may also be produced by lightning during thunderstorms.

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19
Q

What is methane?

A

CH 4 – a gas found in the atmosphere that is produced from methanogenic ruminant bacteria and saprotrophic bacteria.

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20
Q

What are nitrous oxides?

A

NO x – a greenhouse gas that is formed both naturally and by humans, mainly through farming, industry and combustion of fossil fuels.

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21
Q

Diagram showing the average annual methane emissions per type of animal

A
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22
Q

What is carbon dioxide equivalent or CO 2 EQ?

A

-A term for describing different greenhouse gases in a common unit.

-For any quantity and type of greenhouse gas, CO 2 EQ signifies the amount of CO 2 EQ that would have the equivalent global warming impact.

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23
Q

How much of the Earth’s atmosphere do all the greenhouse gases combined make up by volume?

A

Less than 1%

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24
Q

The Earth’s atmosphere is warmed because ___

A

Certain gases in the atmosphere absorb radiation and retain heat.

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25
Q

Two factors that determine how much a greenhouse gas will contribute to global warming are ___ and ___.

A

Ability to absorb longwave radiation

Abundance in atmosphere

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26
Q

Why do some gases cause a greenhouse effect but not others?

A

-The basic reason is that some gases, such as water vapor, carbon dioxide, methane, and nitrogen oxides can absorb longer wavelengths of light and re-emit them as heat.

-However, this does not explain the overall process.

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27
Q

Step 1 of the greenhouse effect

A

-Solar radiation, from the sun, spans the electromagnetic spectrum from approximately 100 to 4 000 nanometres (nm), with visible light comprising about 44% of its emissions.

-After passing through the ozone layer, the layer of the atmosphere that blocks UV radiation but is not considered a greenhouse gas, only short-wavelength radiation from the sun reaches the Earth’s surface.

-Some of the short-wavelength radiation is reflected, but most passes through the greenhouse gases to the Earth’s surface.

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28
Q

Step 2 of the greenhouse effect

A

-The Earth absorbs some of this shortwave radiation while some is reflected.

-This absorbed radiation is then re-emitted, mainly as infrared (heat), which is longwave radiation (with a peak around 10 000 nm).

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29
Q

Step 3 of the greenhouse effect

A

-Part of this longer wavelength radiation escapes Earth’s atmosphere into space.

-However, much of it is absorbed by greenhouse gases in the atmosphere.

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30
Q

Step 4 of the greenhouse effect

A

-The greenhouse gases re-emit the absorbed light in all directions as heat.

-Some of this radiation is re-emitted towards the Earth, thus contributing to global warming.

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31
Q

Define radiation

A

Energy that may be a subatomic particle, for example an electron (gamma rays) or in the form of an electromagnetic wave, for example ultraviolet radiation.

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32
Q

Define solar radiation

A

-Energy from the sun that comes in the form of electromagnetic waves.

-This includes many types of waves such as visible light or ultraviolet light.

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33
Q

What is the ozone layer?

A

-O 3 – is a layer of the Earth’s atmosphere that protects the Earth from ultraviolet radiation coming from the sun.

-It is not considered a greenhouse gas because it does not absorb longwave radiation.

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34
Q

Why is the ozone layer not considered a greenhouse gas?

A

Because it does not absorb longwave radiation.

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35
Q

What is UV radiation?

A

Ultraviolet radiation is a type of shortwave radiation coming from the sun but is filtered out by the ozone layer of the atmosphere.

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36
Q

What is long-wavelength radiation?

A

-Also known as infrared light, a type of radiation that is emitted from the Earth and its atmosphere.

-Examples include microwaves and radiowaves.

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37
Q

What is short-wavelength radiation?

A

-This type of radiation comes from the sun in the form of visible light and ultraviolet light.

-It is absorbed by the Earth and re-emitted as long-wavelength radiation.

38
Q

Diagram showing the sunlight radiation spectrum and re-emitted light from Earth.

A
39
Q

What is infrared radiation?

A

This type of long-wavelength radiation is given off from the Earth in the form of heat.

40
Q

What type of radiation is infrared radiation?

A

Long-wavelength

41
Q

What is global warming?

A

The warming of the Earth and its atmosphere due to the intensified greenhouse effect.

42
Q

Why causes heat retention in the atmosphere?

A

Longwave radiation emitted by the Earth’s surface is first absorbed by greenhouse gases and then re-emitted; this leads to retention of heat in the atmosphere.

43
Q

Diagram summarizing the enhanced greenhouse effect

A
44
Q

What temperature would the Earth’s surface be without the greenhouse gases and the effects they cause?

A

–18 º C

45
Q

Describe the potency and total impact of methane vs. CO2

A

-Methane has a much greater warming effect than carbon dioxide measured per molecule.

-However, the atmospheric methane concentration is much lower, so its total impact is lower as well.

46
Q

Why do carbon dioxide and water vapour have the greatest impact on the greenhouse effect?

A

Because they are present in the highest concentrations in the atmosphere.

47
Q

What is the difference between global warming and the depletion of the ozone layer?

A

-The ozone layer, which is part of the atmosphere, blocks ultraviolet (UV) light. UV light is dangerous for cells, and depleting ozone layer has depleting ability to block this harmful light.

-Global warming is caused by an intensified greenhouse effect.

48
Q

Why are oxides of nitrogen classed as greenhouse gases?

A

Because they trap some of the longwave radiation emitted by the Earth’s surface.

49
Q

The Earth absorbs ___ radiation from the sun and emits ___ radiation.

A

Short-wavelength

Long-wavelength

50
Q

Graph showing the correlation between CO 2 concentration (blue line) and global temperature rise (red line)

A
51
Q

Descrbe the correlation between CO2 concentration and global temperature rise

A

-Not all peaks in the global temperature increase correlate with a higher CO 2 concentration.

-Other factors can influence the global temperature, including sunspot activity and variation in the Earth’s orbit around the sun.

52
Q

What impacts do increases in global temperature have on the Earth’s climate?

A

-Climate change

-Rising seawater

-Loss of habitat

-Biotic factors

53
Q

Explain how increases in global temperature impact climate change

A

Higher global averages mean that the total amount of water that evaporates from oceans and lakes increases.

-More water in the atmosphere leads to heavier rainfall.

-Global warming can also have substantial effects on wind and ocean currents causing stronger hurricanes and typhoons.

54
Q

Explain how increases in global temperature impact rising seawater

A

Another consequence of the increased global temperature is the rising seawater temperature and the melting effect on the polar ice caps and glaciers around the world.

55
Q

Explain how increases in global temperature impact loss of habitat

A

-The polar ice caps and glaciers are melting, decreasing ice habitats for some arctic organisms.

-Also, when these ice caps melt they cause a rise in sea levels, as mentioned above, destroying coastal habitats.

56
Q

Explain how increases in global temperature impact biotic factors

A

-The warming of any habitat would change the species that live in the area and can cause changes to migratory patterns.

-Temperate species move into warmer arctic areas and compete with the arctic species.

-Arctic species need to adapt to competition and the change in temperature or emigrate to a new habitat.

-This would cause a change in the distribution of species, possibly a decrease in population sizes and, in extreme cases, extinction of species.

-Changes such as these could have severe impacts on the food chains of an ecosystem disrupting the food web and having a large impact on organisms in higher trophic levels.

-Other effects on the biota may be an increase in decomposition due to melting permafrost, which exposes saprotrophic bacteria to oxygen, releases methane, and, with an increase in temperature and moisture there will be an increase in pest species and pathogens.

57
Q

What is climate?

A

Long-term weather patterns in an area or region

58
Q

What is climate change?

A

Changes in the long-term weather patterns in an area or region due to the intensified greenhouse effect.

59
Q

Why are global temperatures and climate patterns influenced by changing concentrations of greenhouse gases?

A

Because greenhouse gases affect global temperatures and the latter in turn affects climate patterns.

60
Q

How are changes in the Earth’s climate distributed?

A

-The changes that are occurring are often unevenly distributed.

-In some areas, rainfall may increase, while in others the incidence of droughts increases.

61
Q

What is the general concensus among scientists about whether or not the climate is changing?

A

Based on the weather patterns and phenomena that have been observed during the last 30 years, there is little doubt among scientists that the Earth’s climate is changing.

62
Q

What do scientists believe is the main reason for climate change and how do they know this?

A

-There is agreement that the main reasons for the increase in atmospheric CO 2 concentrations are related to human activities.

-An important culprit is the increased use of fossil fuels since the industrial revolution.

-This conclusion has been reached by looking at historical records of human activities and comparing them to records of rising amounts of greenhouse gases.

-Since the start of the industrial revolution 200 years ago, we have been burning fossil fuels, as well as clearing and burning forested land at an unparalleled rate.

-Both of these processes convert organic carbon into CO 2.

-Furthermore, deforestation means that there are less autotrophs using atmospheric CO 2 during photosynthesis.

63
Q

What is the role of the oceans and territorial biosphere in absorbing CO2?

A

-Calculations show that the amount of CO 2 produced by combustion of fossil fuels and deforestation should have been far more than what is now found in the atmosphere.

-This can be explained by the fact that our oceans and the terrestrial biosphere have the ability to absorb some of the CO 2 we produce.

-This, in turn, causes its own problems, such as ocean acidification.

-It is a fact that we generate CO 2 at a faster rate than the oceans and biosphere can absorb it.

-This explains the observed increase in atmospheric CO 2 and therefore an intensified natural greenhouse effect.

64
Q

What is the cause of the more recent increases in atmospheric carbon dioxide?

A

The combustion of fossil fuels

65
Q

When does the combustion of fossil fuels occur?

A

-In vehicles used for transport

-When homes are heated

-During the production of electricity

-In factories powered by fossil fuels

-Burning of forests for clearing.

66
Q

Describe the political controversy around climate change

A

-There are many published findings that either support or refute a connection between human activities and the climate changes we are experiencing.

-The discussion around climate change is charged, political and controversial.

-It is the scientists’ responsibility to assess the validity of claims.

-The consequences of climate change could be catastrophic at both an ecological and economic level.

-Politicians need to base their policies on exact science, not gut feelings or biased reporting in the popular media.

67
Q

Correlation vs. causation for climate change

A

-It should be noted that although there is a correlation between global temperatures and CO 2 concentrations on Earth, there is little evidence to support a direct causal relationship between the two through the millennia.

-Therefore, we cannot state with absolute certainty that human-caused CO 2 emissions are the main cause of global warming and climate change.

68
Q

What is a precautionary principle?

A

Also known as the burden of proof, this principle states that even without concrete evidence of a causal relationship, precautionary measures should be taken to ensure that humans are not causing detrimental harm to the environment or human health.

69
Q

If humans start to see devastating effects in the environment, such as melting ice caps, but not clear evidence suggesting that it is caused by human action, such as the burning of fossil fuels, which statement about the precautionary principle would be appropriate?

A

Because it is probable that combustion of fossil fuels are causing devastating environmental effects, people should be educated on the consequences and laws that require cleaner filtering systems for industries.

70
Q

What is a coral reef?

A

-A ridge in the ocean where living coral polyps attach and secrete calcium carbonate.

-Coral reefs are typically very diverse places found in warm shallow waters.

71
Q

How can greenhouse gases (e.g. CO2) make oceans more acidic?

A

-Because of the heavier rainfall associated with global warming, more of these molecules dissolve into rain water from the atmosphere, falling onto land, rivers, lakes, and oceans as acid rain.

-Carbon dioxide is more dense than other atmospheric components and, therefore, is typically found at the surface of the Earth including oceans.

-This CO2 can dissolve directly into aquatic environments such as rivers, lakes, and oceans as well.

-Carbon dioxide combines with water to form carbonic acid: H2CO3.

-This molecule easily dissociates into H+ and HCO3-.

-The H+ freed in this dissociation lowers the pH of water, making it more acidic.

72
Q

Graph which extrapolates the increasing CO2 concentration in ocean water (rojection of dissolved CO2 versus ocean pH)

A
73
Q

What is ocean acidification?

A

-The drop in pH of the ocean due to the absorption of carbon dioxide, which forms carbonic acid.

-The H+ ions become dissociated from carbonic acid, causing the water to become acidic.

74
Q

Diagram explaining ocean acidification

A
75
Q

Steps of ocean acidification

A

-Carbon dioxide from the atmosphere is absorbed by the ocean.

-Carbon dioxide absorbed by the ocean is broken down, forming carbonic acid and hydrogen ions.

-As hydrogen ions form bonds with carbonate atoms, bicarbonate atoms form. The concentration of carbonate atoms is therefore reduced.

-Shells and coral of marine life are calcium-based and organisms use carbonate atoms to build and maintain these structures.

76
Q

Explain the effect that ocean acidification has on living organisms in the ocean

A

-A lowering of the pH increases the solubility of calcium carbonate (hydrogen ions bond to the carbonate in place of calcium), decreasing the amount of CaCO3 that is readily available to living organisms.

-Calcium carbonate is used by marine organisms such as crustaceans, molluscs and corals to build their exoskeletons and shells, a process known as calcification.

-If less CaCO3 is available, it will slow the building of coral reefs and make them more brittle.

-As the coral CaCO3 exoskeletons also begin to dissolve, they will become less resilient to other factors influencing their survival.

77
Q

What is calcification?

A

The process used by molluscs, crustaceans, and corals to build their shells and exoskeletons using calcium carbonate.

78
Q

Describe the threat to the life of coral reefs due to ocean acidification

A

-Although coral reefs are naturally very resistant to many of these threats, their ability to re-colonise and grow stable structures is affected by ocean acidification.

-If the pH decreases even more, the change may actually destroy the reefs by dissolving the coral exoskeletons.

-Once the coral has been killed off, coral habitats will be gradually replaced by non-calcifying organisms such as seagrass, resulting in underwater grasslands.

79
Q

Picture of underwater grasslands - a possible consequence of disappearing coral reefs

A
80
Q

What threat does ocean acidification pose to mollusc shells such a the pteropod?

A

These molluscs use calcium carbonate to build their shells, so as less calcium carbonate is available to them due to the rise in acidity of the ocean, their shells will become weaker.

81
Q

Picture showing how pteropod shells affected by ocean acidification

A
82
Q

Data-based questions relating to ocean acidification

A

Be prepared to analyse data-based questions about the effects of a rise in temperature and acidity on marine organisms.

83
Q

How does the increase in water temperature pose a threat to marine organisms?

A

-While acidic oceans are certainly a problem for marine organisms that use calcium carbonate, the increase in water temperature also poses a threat.

-Marine organisms, including corals, are very sensitive to temperature changes in their environment.

-They will need to adapt to these changes or they will become extinct, decreasing the biodiversity of the oceans.

84
Q

How are food chains disrupted by ocean acidification?

A

Many of the organisms affected by ocean acidification and a rise in temperature are important food sources for corals. Their destruction disrupts the food chain.

85
Q

What impact are increasing concentrations of dissolved carbon dioxide likely to have on corals and why?

A

Since increasing concentrations of dissolved carbon dioxide leads to ocean acidification, it is very likely to have a negative impact on the ability of corals to develop, and on their ability to recover from damage.

86
Q

What is the main cause of the dissolution of the calcium carbonate exoskeletons?

A

Ocean’s pH has dropped

87
Q

An increase in the concentration of dissolved carbon dioxide represents a threat for coral reefs because ___

A

It will reduce calcification in corals and make them more brittle.

88
Q

Which greenhouse gas makes the largest percentage contribution to the greenhouse effect?

A

Water vapor

89
Q

What term is used to describe the deposition of calcium carbonate in the building of coral reefs?

A

Calcification

90
Q

Outline the threat to coral reefs from increasing concentrations of dissolved CO2 (OSC)

A

-Increased amounts of CO2 dissolved in the ocean has caused the ocean to become more acidic since CO2 reacts with water to form carbonic acid (which dissociates)

-Hydrogen ions react with carbonate ions and reduce carbonate ion concentrations

-Carbonate ions are required by coral to synthesize calcium carbonate for their skeletons

-Coral will grow more slowly

-Hydrogen ions can also react with teh calcium carbonate skeletons of teh corals and cause them to break down

IB HL Biology (68 decks)

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