1.1 Hazardous Earth

Question 1

how does climate vary with latitude?

Answer 1

with distance from the equator:
temps decrease
range of temps increase
precipitation fluctuates

Question 2

why does temp decrease w distance from the equator?

Answer 2

in areas closer to the poles, incoming solar radiation has a thicker atmosphere to travel through due to the curvature of the Earth. the sun is also at a lower angle in the sky, so solar radiation is spread across a larger area.

Question 3

name the three global circulatory cells.

Answer 3

hadley cell; ferrel cell; polar cell

Question 4

describe how the global circulation system works

Answer 4

warm air at Equator rises and moves away; as it cools, it descends at the tropics, creating the hadley cell
cold air at the poles descends; then moves away towards the mid latitudes, creating the polar cell
cold air from poles meets warm air from tropics in the mid latitudes, creating the ferrel cell

Question 5

what is atmospheric pressure

Answer 5

the weight of the air and the force it exerts on the ground

Question 6

why do areas of high pressure have low precipitation?

Answer 6

cooled air descends, exerting more pressure on ground and resulting in dry, stable conditions

Question 7

why do areas of low pressure have high precipitation?

Answer 7

warmed air is unstable and rises, exerting less pressure on ground; as air rises, it cools and cannot hold as much water vapour, resulting in condensation, cloud formation, and precipitation

Question 8

explain how ocean currents redistribute heat.

Answer 8

surface ocean currents are driven by wind across the top of the water, whereas deep ocean currents are driven by water sinking and rising bc of temp changes
(extra e.g. : cold water from arctic sinks, drawing in warmer water from south)

Question 9

describe how volcanic activity can affect climate.

Answer 9

they produce ash and sulphur dioxide gas; if these rise high enough, they’ll spread around the Earth’s stratosphere; this blanket will stop some sunlight reaching the Earth’s surface and instead will reflect it back into space; this cools the planet and the average temperature
e.g.1815 eruption of Tambura - in 1816, temps were so cold that 200,000 people died in Europe dur to harvest fail

Question 10

describe how variation in solar output can affect climate.

Answer 10

black spots on the surface of the sun called sunspots disappear and reappear at different times; lots of sunspots mean more solar energy is being fired out, causing temp increases; less cause temp decreases
e.g. the cooler period known as the Little Ice Age may have been caused by sunspot activity

Question 11

describe how orbital changes (milankovitch cycles) can affect climate.

Answer 11

over very long periods of time, the Earth’s orbit changes (known as Milankovitch cycles): it is sometime is more circular or more elliptic; sometimes the axis is more upright, or more on the side; sometimes the axis wobbles. these alter the amount of sunlight the Earth receives and where sunlight falls
e.g. these changes over tens of thousands of years would be enough to start or end an ice age

Question 12

describe how asteroid collisions can affect climate.

Answer 12

every once in a while, an asteroid comes in contact w Earth; these can release huge quantities of vaporised material into the atmosphere, blocking the sun and causing a potential temp. drop of 5-6 degrees - initial ‘impact winter’; can also cause forest fires due to large amounts of CO2 released
e.g. asteroid collision theory considered to account for the extinction of the dinosaurs 65 million years ago.

Question 13

how can historical sources be used for evidence for natural climate change?

Answer 13

personal diaries e.g. Anglo Saxon chronicles record years of droughts and heavy rainfall
paintings e.g. Painting of River Thames, 1963, during the Little Ice Age
religious records

Question 14

how can tree rings be used for evidence for natural climate change?

Answer 14

every ring represents a year of growth; wider rings suggest the year was wetter and/or warmer; thinner rings suggest the opposite; black marks = scars from forest fires - suggest year was warmer and/or drier

Question 15

how can ice cores be used for evidence for natural climate change?

Answer 15

a drill extracts an ice core; bubbles in ice trap ancient atmosphere - ghg content can be measured for particular years, allowing us to model past climate

Question 16

what human activities produce CO2?

Answer 16

deforestation; power stations; cars

burning of fossil fuels and organic material

Question 17

what activities produce methane?

Answer 17

cows; landfill sites; rice fields; peat bogs

all organic matter

Question 18

what is the greenhouse effect?

Answer 18

the natural trapping of sun’s energy in the atmosphere due to the presence of greenhouse gases

Question 19

what is the enhanced greenhouse effect?

Answer 19

the increased greenhouse effect resulting from human activity, leading to global warming

Question 20

how does human activity enhance greenhouse effect?

Answer 20

layer of greenhouse gases above atmosphere gets thicker; sun emits short wave radiation which passes through the atmosphere and ghg layer; it is reflected off the surface and becomes long wave radiation; some long wave radiation passes back into space; some is reflected off ghg layer back to earth, heating it up

Question 21

why do CO2 levels increase over time?

Answer 21

increase in population => increase in demand for energy => increase in no. of power stations => increase in CO2 as fossil fuels are burned ( => enhanced greenhouse effect)
increase in population => increase in demand for food => deforestation esp. tropical rainforests, to provide space for farming or for resources such as palm oil => less CO2 removed from atmosphere; when burned / rotted, they release stored carbon as CO2 ( => enhanced greenhouse effect)`

Question 22

what is the evidence for how human activity is causing climate change? (surface air temps change, upper ocean temps change, sea level change, arctic sea ice change, mountain glacier change, changes in extreme weather events)

Answer 22

surface air temps have increased - 2016 has been the hottest year recorded; 2010s has been the hottest decade
upper ocean temps have increased - areas of arctic and pacific ocean have increased the most
sea level has increased - by 20cm; floods have damages small pacific islands e.g. Marshall islands
arctic ice has decreased - b 2.8 million sq kms
mountain glaciers are melting/thinning
extreme weather disasters are increasing overall

Question 23

what are the consequences of climate change on people in the UK?

Answer 23

increase in flooding = flooding damage costs rising from £1 billion a year to £2 to £12 billion by 2080; rising sea levels & more extreme storms = increase in coastal flooding and erosion - threatening homes and transport, more investment in coastal defences to reduce erosion and flooding
domestic tourism likely to grow e.g. coastal resorts like Blackpool

Question 24

what are the consequences of climate change on people in egypt?

Answer 24

up to 20% less rainfall in parts of egypt and sudan = discharge of nile is reduced = less water for irrigation and conflict w neighbouring countries
global sea level rise = 15% of egypt’s land permanently flooded = 7m people displaced from homes; and less land for agriculture = lower crop yields for commercial and subsistence = undernourishment of poorest and lack of foreign income

Question 25

what are the consequences of climate change on people in nepal?

Answer 25

reduced precipitation and reduced water from ice in dry season = water shortage - increase in malnutrition; irrigation problems - decrease in crop yield by 30% by end of century
increase in precipitation during monsoon season = river flooding & landslides in mountainous areas = increase in environmental refugees
increase in snow and ice loss (20%) = increase in glacial lake outburst = water pressure on dams = dams bursting and flooding valleys below, threatening villages downstream

Question 26

what are the consequences of climate change on people in the maldives?

Answer 26

rising sea levels = homes & tourism near coast threatened - almost all inhabitants will be affected, almost all resorts and the two international airports lie within 50m of coastline
small increases in sea level = worsening of existing environmental issues e.g. persistent flooding
predicted sea level rise by 50cm by 2100 = country loses 77% of land area = increase in environmental refugees

Question 27

why is there uncertainty over the projections for global temp. change? (7 reasons)

Answer 27

future technology; future deforestation; future population change; future energy sources; future economic growth; changes in attitude; natural climate change

Question 28

how does future population change create uncertainty for global temp change?

Answer 28

we do not know how the population will change, therefore we do not know how much food, energy, electricity, transport etc. will be needed to suffice

Question 29

how does future economic growth create uncertainty for global temp change?

Answer 29

uncertainty over future economic growth = uncertainty over global temp change; we do not know how diff countries will cont. to economically e.g. some developing countries could have oil-based growth

Question 30

how does future energy supply create uncertainty for global temp change?

Answer 30

we don’t know what kind of energy (non-renewable, renewable) will be predominantly used; we do not know how much ghgs will be emitted

Question 31

how does natural climate change create uncertainty for global temp change?

Answer 31

periods of increased sun spot activity would lead to increases in global temp.; whereas volcanic activity could block incoming solar radiation and lead to a decreases in global temp.

Question 32

why is there uncertainty over the projections for global seal level rise?

Answer 32

we do not know who future temp will rise (so all previous factors); we do not how much land ice will melt; we do not know how much the ocean will expand by thermal expansion