Eduqas GCSE Geology · 2.4

Global Climate and Sea Level Change

50 revision questions with answers for 2.4 Global Climate and Sea Level Change in Eduqas GCSE Geology (spec C480QS). Practise with flashcards, a topic quiz, a random quiz across the course, 5 crosswords, Five Degrees, Associations, or read every question and answer below.

All 50 questions and answers

Question 1
What is an icehouse climate?
Answer:
A relatively cool global climate in which substantial long-lived ice sheets can exist.
Question 2
What is a greenhouse climate?
Answer:
A relatively warm global climate with much less persistent polar ice and generally higher global temperatures.
Question 3
What evidence can ancient glacial tillite provide?
Answer:
It records deposition by ice and can indicate former glacial conditions in that location.
Question 4
Why are Carboniferous tillites near the present equator significant?
Answer:
They indicate that those areas once experienced glacial conditions, though their latitude may also have changed.
Question 5
What can chalk or limestone outside today's tropics indicate?
Answer:
Past conditions suitable for abundant carbonate deposition, potentially warmer and/or at a different latitude.
Question 6
Why must both climate and latitude be considered when interpreting old rocks?
Answer:
Continents move, so a rock's present latitude may differ from its depositional latitude.
Question 7
How can fossil plants provide evidence about past climate?
Answer:
Their types and adaptations can indicate the temperature or moisture conditions in which they grew.
Question 8
How can glacial striations inform climate reconstruction?
Answer:
Scratches on bedrock can indicate former ice movement and the presence of glaciers.
Question 9
What are ice cores?
Answer:
Cylinders drilled from accumulated ice that preserve layered records of past environmental conditions.
Question 10
How can ice cores indicate past atmospheric carbon dioxide?
Answer:
Bubbles trapped in the ice contain samples of ancient air that can be analysed.
Question 11
Why do older ice-core layers generally occur below younger layers?
Answer:
Snow accumulates on top of earlier layers, which are gradually buried and compressed.
Question 12
Why can sedimentary rocks help reconstruct climate further back than ice cores?
Answer:
Some rocks preserve geological and chemical evidence over much longer timescales than surviving ice.
Question 13
Why should climate interpretations use more than one line of evidence?
Answer:
Different proxies have uncertainties; agreement between independent evidence strengthens a conclusion.
Question 14
How can Britain have deposited tropical limestones despite its current latitude?
Answer:
The British area was at a different latitude in the past and experienced different climate conditions.
Question 15
What does a palaeogeographic map show?
Answer:
The interpreted positions of continents and environments at a particular time in the past.
Question 16
Why must a latitude-versus-time graph be read with its axis directions checked?
Answer:
Time may run in either direction and latitudes north and south have different signs or labels.
Question 17
Latitude changes from 30 degrees south to 10 degrees south over 100 Ma. Calculate the mean change.
Answer:
20 degrees / 100 Ma = 0.2 degrees per million years northward.
Question 18
What geological process moves the British area between latitudes over millions of years?
Answer:
Plate motion.
Question 19
Does a warmer climate necessarily prove that a continent moved towards the equator?
Answer:
No. Global climate change can also cause warming; combine latitude and climate evidence.
Question 20
What can a drowned forest tell geologists?
Answer:
A landscape once above water has been submerged, indicating relative sea level rose or land sank.
Question 21
How can melting land-based ice sheets affect global sea level?
Answer:
Water added to the oceans tends to raise global sea level.
Question 22
How does ocean warming affect sea level?
Answer:
Seawater expands as it warms, contributing to sea-level rise.
Question 23
Does the melting of floating sea ice have the same direct effect as melting land ice?
Answer:
No. Floating ice already displaces seawater; land ice adds water to the ocean when it melts.
Question 24
Why is a drowned forest evidence for relative rather than global sea-level change on its own?
Answer:
The local change could reflect sea-level rise, land subsidence, or both.
Question 25
How can maps and aerial images help investigate ice-sheet change?
Answer:
Images from different dates show changes in ice extent when compared on the same scale.
Question 26
A shoreline moves inland. What geological changes might explain this?
Answer:
Relative sea-level rise, subsidence or coastal erosion can move the shoreline inland.
Question 27
Name two sources of atmospheric carbon dioxide in the specification.
Answer:
Volcanic emissions and the burning of fossil fuels.
Question 28
How does burning fossil fuels affect the carbon cycle?
Answer:
It transfers carbon stored underground to the atmosphere, mainly as carbon dioxide.
Question 29
How does volcanism affect atmospheric carbon dioxide?
Answer:
Volcanic activity releases carbon dioxide from Earth's interior.
Question 30
Which source dominates the present increase in atmospheric carbon dioxide: human fossil-fuel emissions or volcanic emissions?
Answer:
Human activities, particularly fossil-fuel burning, release substantially more CO2 annually than volcanoes.
Question 31
Why can atmospheric carbon dioxide influence global temperature?
Answer:
CO2 absorbs outgoing infrared radiation, strengthening the greenhouse effect as its concentration rises.
Question 32
A CO2 value rises from 300 ppm to 360 ppm. Calculate the percentage increase.
Answer:
(360 - 300) / 300 x 100 = 20%.
Question 33
A graph rises from 280 to 320 ppm over 20 years. Calculate the mean annual change.
Answer:
(320 - 280) / 20 = 2 ppm per year.
Question 34
What does ppm mean for atmospheric carbon dioxide?
Answer:
Parts per million: the approximate number of CO2 molecules per million molecules of air.
Question 35
Why does a rising CO2 graph not by itself establish the source of the increase?
Answer:
Other evidence, such as emissions inventories and isotopic measurements, is needed to attribute sources.
Question 36
What is a positive climate feedback?
Answer:
A change that amplifies an initial change in the climate system.
Question 37
How can melting ice create a positive warming feedback?
Answer:
Less reflective ice exposes darker surfaces, which absorb more solar energy and promote further warming.
Question 38
What is albedo?
Answer:
The fraction of incoming sunlight reflected by a surface.
Question 39
Why is ice generally high in albedo?
Answer:
Its bright surface reflects a relatively large fraction of incoming sunlight.
Question 40
What is a negative feedback?
Answer:
A response that tends to reduce the size of an initial change.
Question 41
How can carbon dioxide dissolve in the ocean affect atmospheric CO2?
Answer:
The ocean can absorb some CO2, reducing the amount remaining in the atmosphere.
Question 42
How can carbonate organisms contribute to long-term carbon storage?
Answer:
They use dissolved carbon to make shells or skeletons, some of which become carbonate sediment and rock.
Question 43
How can chemical weathering contribute to long-term carbon cycling?
Answer:
Reactions involving atmospheric CO2 and rocks transfer carbon to dissolved products that can reach the oceans.
Question 44
How can subduction and volcanism connect stored carbon to the atmosphere?
Answer:
Carbon-bearing material is carried into Earth's interior; some carbon is eventually released through volcanism.
Question 45
Why is feedback different from an initial cause of warming?
Answer:
A feedback responds to an initial change and then amplifies or counteracts it.
Question 46
What is geological carbon capture and storage?
Answer:
Capturing CO2 and injecting it into suitable deep geological formations for long-term containment.
Question 47
Why is a cap rock important for geological CO2 storage?
Answer:
A low-permeability seal helps prevent injected CO2 migrating upward.
Question 48
Why must a storage site be monitored?
Answer:
Monitoring helps detect unexpected migration or leakage and assess the effectiveness of the storage.
Question 49
Why does carbon capture complement rather than automatically replace emission cuts?
Answer:
Storage capacity, capture efficiency, leakage risk and energy use mean not every emission is necessarily captured.
Question 50
What properties make a deep formation potentially suitable for CO2 storage?
Answer:
Connected pore space for injection and storage, plus an effective low-permeability seal and suitable geology.

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Global Climate and Sea Level Change

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