Climate Change & It's Causes

Question 1

what are the 3 ways to measure long-term climate change? Explain each one

Answer 1

1. ice cores: air bubbles, CO2
2. oceans: O2 isotopes, thermohaline circulation
3. pollen: peat bogs, plant species

Question 2

which two ways are the most reliable ways to measure long-term climate change

Answer 2

ice cores & oceans

Question 3

why are pollen samples not very reliable ways of seeing long-term climate change?

Answer 3

• rare to get long pollen sequences of data

- plants may ‘lag’ behind/ can’t evolve as quickly as climates change

Question 4

what are the two ways to measure medium-term climate change?

Answer 4

1. historical records: analyse old photos/paintings

2. tree rings: measure thickness of annual growth rings

Question 5

why isn’t looking at historical records not a very reliable way to measure medium-term climate change?

Answer 5

proxy records = paintings not intentionally created to document climate, subjective data

Question 6

what evidence is there to prove that proxy records may be useful for measuring medium-term climate change?

Answer 6

Little Ice Age period: shown through retreating glaciers in painting & ice skaters on frozen river Thames in 1800s

Question 7

what is the down side to measuring the width of tree rings to measure medium-term climate change?

Answer 7

info can’t be generalised globally, only informs about climate change in area local to trees

Question 8

what two ways are used to measure recent climate change?

Answer 8

1. the instrumental record: weather stations

2. ice response: monitoring glacial retreat

Question 9

what evidence has been gathered from the instrumental records to prove that drastic climate change has happened recently?

Answer 9

• 11/12 worlds hottest years (since 1850) occurred from 1995-2006
• ocean buoys data showed that thermal expansion is responsible for 60% sea level rise
• ocean acidification (too much CO2 in water) = coral reef species dying

Question 10

what data has been collected using ice response to prove that climate change has only happened recently?

Answer 10

• greenland ice sheet increased melting by 16%, since 1979
• arctic ocean free of ice in summer of 2060
• world glacier monitoring service: 30 valley glaciers, in 9 mountain ranges, melting 3 times faster

Question 11

what are 3 physical and 2 human drivers of climate change?

Answer 11

1. P: milankovitch cycles
2. P: solar sunspots
3. P: volanic causes
4. H: Enhanced Greenhouse Effect
5. H: global dimming

Question 12

what are the 3 cycles in the milankovitch cycles?

Answer 12

1. earth’s orbit
2. earths axis
3. axial precession

Question 13

how does the shape of the earths orbit affect climate change?

Answer 13

elliptical = hotter summers/colder winters
circular = even distribution of solar energy

Question 14

how often does the shape of the earths orbit change?

Answer 14

every 100, 000 years

Question 15

whats the minimum & maximum tilt of the earths axis?

Answer 15

21.5 - 24.5 degrees

Question 16

how does the earths axis affect climate change?

Answer 16

smaller the tilt, the less difference in temp between summers & winters

Question 17

how often does the earths axis change?

Answer 17

every 41, 000 yrs

Question 18

how often does axial precession take place?

Answer 18

every 22, 000 yrs

Question 19

what is axial precession & how does it affect climate change?

Answer 19

earth’s axis wobbles, changes the point in the year that earth is closest to the sun, so earth may be closer to sun in September = indian summer in northern hemisphere

Question 20

what is evidence to support the theory that milankovitch cycles really impact climate change?

Answer 20

ice ages occur every 100,000 yrs, same as time scale for earths orbit changing shape

Question 21

what evidence disproves the theory that milankovitch cycles don’t heavily impact dramatic climate change?

Answer 21

• only enough to decrease world temp by 0.5 degrees
• ice ages are 5deg colder than non-glacial intervals
• positive feedback mechanisms sustain/amplify the 0.5deg decrease to 5deg decrease
• milankovitch cycles only trigger global climate change

Question 22

what positive feedback mechanism is an example of how they sustain global climate change?

Answer 22

• small increase in ice
• raise albedo
• more sunlight reflected into space
• earth cools
• encourages further snowfall

Question 23

how do sunspots affect climate change?

Answer 23

they blast more radiation toward earth = hotter

Question 24

how often do sunspots occur?

Answer 24

11-yr cycle

Question 25

what 3 pieces of evidence is there to prove that sunspots are the cause of major climate change?

Answer 25

• maunder minimum: 1645 - 1715, Little Ice Age, no sunspots
• medieval warm period
• 20% warming in 20th century due to sunspots

Question 26

how do volcanic eruptions effect climate change?

Answer 26

• ejected material of sulphur dioxide, ash, CO2
• winds distribute material around world
• aerosols block sunlight

Question 27

how many tonnes of materials were ejected by mt. pinatubo in 1991?

Answer 27

17 million of sulphur dioxide

Question 28

what evidence is there that volcanic eruptions heavily impact climate change?

Answer 28

‘year without summer’, 1816, Tambora eruption

Question 29

what evidence is there that volcanic eruptions only slightly impact climate change>

Answer 29

short - lived aerosols, only stay around for 2-3yrs

Question 30

what evidence is there to prove that recent climate change is mainly due to enhanced greenhouse effect?

Answer 30

11/12 years of world hottest, since 1850, occurred in 1995-2006

Question 31

how does global dimming affect climate change?

Answer 31

particulates, sulphur dioxide & soot, reflect sunlight back into space, net cooling effect

Question 32

what evidence is there to suggest that global dimming may largely affect climate change?

Answer 32

North America & Europe stopped polluting sulphur dioxide & soot to stop acid rain since the 90s, global warming has accelerated since the 90s due to no particulates reflecting sunlight back into space
is human pollution useful in this way?