Greenhouse Effect and Climate Change Flashcards
What happens to UV as it passes through the atmosphere?
UVC and UVB is absorbed by ozone, water vapour, oxygen and CO2
UVA passes through
What happens to infra-red as it passes through the atmosphere?
50% does not reach the surface
absorbed by greenhouse gases in the troposphere
50% is absorbed
What happens to visible light as it passes through the atmosphere?
all of it reaches earth, except for a small amount that is reflected (e.g. by the clouds)
Greenhouse effect: Step 1
earth receives energy from sun in from of UV, visible light and infra-red
Greenhouse effect: Step 2
visible light is transmitted, infra-red is absorbed by GHGs, UVB and UVC is absorbed by atmosphere, UVA passes through except for small amount that is reflected
Greenhouse effect: Step 3
radiation that reach the earth’s surface is absorbed and re-emitted as infra-red radiation
Greenhouse effect: Step 4
greenhouse gases absorb this energy and emit some of it back towards earth
Greenhouse effect: Step 5
the earth warms due to the greenhouse gases re-emitting infrared radiation towards earth, this is essential for sustaining life
Define: Greenhouse effect
the warming of the atmosphere due to insulation by greenhouse gases
Define: Enhanced Greenhouse effect
the impact on the climate from the additional heat retained due to the increased amounts of carbon dioxide and other GHGs that humans have released into the atmosphere since the industrial revolution
Define: Anthropogenic
human cause
Anthropogenic Sources: CO2
agriculture
power generation/ transportation = combustion of fossil fuels
chemical production
Anthropogenic Sources: Methane
landfills
agriculture
oil and gas systems
coal mining
wastewater treatment
Anthropogenic Sources: Nitrogen Oxides
combustion of fossil fuels (cars)
refining of petrol + metals
commercial + food manufacturing
Anthropogenic Sources: Chlorofluorocarbons
air conditioning
refrigeration
insulation + packaging materials
aerosols + solvents
Anthropogenic Sources: Tropospheric Ozone
product of photochemical reactions
fossil fuel combustion
agriculture
What is the most damaging per molecule greenhouse gas?
tropospheric ozone
Personal choices that reduce greenhouse gas emissions
public transport
recycle
solar panels/lighting
adjust thermostat
plant trees
hybrid/electric cars
How much more damaging is methane compared to carbon dioxide?
25x
Why is so much effort being put in to reducing CO2 emissions?
a higher amount of CO2 is emitted into the atmosphere than any of the other gases
How much more damaging are CFCs compared to methane?
224x
How can the UK reduce greenhouse gas emissions?
renewable energy initiatives
change building regulations/planning policy
increase fossil fuel taxes
close landfill sites
invest in public transport
protect green spaces
Why are sea levels likely to rise if average global temperatures increase?
ice melts - volume of liquid increases - sea levels rise
What areas of the world are most at risk from flooding?
oceanic islands
central america
How does the Earth’s climate system work?
energy from sun moves in and out, heat moves around atmosphere and seas
some energy is reflected/absorbed
energy that is absorbed is re-radiated
GHGs re-emit the heat they absorb - eventually into space
warm air rises and cool air sinks
How does the Earth’s climate system redistribute heat at the equator?
ocean currents - warm surface waters move from equator to the poles
convection cells
What aspects of the climate might be changed if world temperatures increase?
frequency of extreme weather
sea level rise
reduced ice/snow cover
increase ocean acidification
changes in ocean currents
increase precipitation
What are the four factors that drive ocean currents?
temperature
salinity
prevailing winds
evaporation
Where is warm water found and at what depth?
equatorial waters
surface depth (100m)
What happens as warm water moves from the equator?
cools, becomes denser, sinks
What two factors increase as water cools?
density
salinity
Define thermohaline circulation
circulation driven by salinity and temperature
How does the gulf stream work?
10000km long
warm and fast moving water
SE trade wind - prevailing wind
What effect does the North Atlantic Conveyer have on Northern Europe?
incoming warm water releases heat into the atmosphere - makes the UK warmer than other countries at the same latitude
What is the possible impact of temperature increase on the North Atlantic Conveyer?
current is weakened
north atlantic ocean cools
europe would cool 5-10 degrees
What happens in the Pacific ocean in a normal year?
east to west prevailing wind - easterly trade wind
warm waters are pushed to the west
upwelling of cold water from the deep in the east
west = warm humid rising air - unsettled weather
east = cool air falling - settled weather
What happens in the Pacific ocean in an El Nino year?
trade winds are weakened or reversed
warm water is central or to the east of the pacific
warm humid air rises in the centre - unsettled weather
What happens in the Pacific ocean in a La Nina year?
trade winds are stronger
larger area of cold water upwelling in the east
small area of warm water in the west
How have weather events associated with El Nino affected significant events in world history?
Spanish conquest - allowed them to travel further down the south american coast
18th century - crop failures in europe led to unrest causing the french revolution
Define cryosphere
the regions on earth where water freezes into snow or ice
Define ice sheet
ice covering an area over 50000 km2
Define ice cap
ice covering an area less than 50000 km2
has its own topography
Define ice field
ice covering an area less than 50000 km2
topography of ice follows the underlying land
Define glacier
a large body of dense ice moving over the land under its own weight
Define ice shelf
floating mass of ice attached to ice on land
Define iceberg
large piece of ice floating in the sea that broke off a glacier or ice shelf
Define sea ice
thin ice that forms on the sea as water freezes
Impact of climate change on living things
habitat loss
lower crop yield
intense droughts
change in ranging behaviours
change in hibernation
faster plant growth
change in migration
change in breeding behaviours
What does range of tolerance mean?
range of environmental conditions that are tolerable for survival in a species
Consequences of changes in abiotic factors, but no change in range of tolerance
migration
death/extinction in local area
What factors may hinder species trying to change their geographical range?
expanses of water
mountains
urbanisation
predators
availability of resources
Climate change case study: bats
population decrease
migration patterns altered
different diseases
loss of insect prey
hibernation patterns changed
Impact of climate change on health, food security and water security
higher food costs
decreasing yields
ocean acidification - fish decrease
heat stroke
more frequent sever weather
increase of pathogens
Impact of climate change on human settlements
loss of major cities
loss of shade from urban trees
flooding risks, salt water intrusion, severe storms = coastal regions
Impacts of climate change on society
conflicts over resources
desertification
increase in landslides
displacement due to natural disasters
Why is it difficult to predict climate change?
time lag between cause and effect
hard to differentiate between weather and climate
lots of positive and negative feedback mechanisms (positive = accelerate effects, negative = cancel out effects)
climate change can be natural
Define positive feedback
a process that exacerbates the effects of a small disturbance
Define negative feedback
a process that reduces the result of a reaction to bring the system back to a stable state
What is meant by tipping point?
a threshold, that when crossed, leads to larger and often irreversible changes in the climate system
Monitoring the climate: monitoring ocean currents
measured using radar and satellite
driven by salinity/temperature/prevailing winds/evaporation
argo floats - beam to satellites
Monitoring the climate: computer models
help to predict climate change
feed in data from many different sources
How can we improve our confidence about computer models?
input data from past events and see if the model predicts the correct outcome
What does per capita mean?
per person
Calculation for per capita?
total/population
Define carbon footprint
measure of the amount of CO2 released into the atmosphere as a result of the activities of a particular individual/business/community
Control measures: carbon dioxide
reduce combustion of fossil fuels
flight tax
invest in renewable energy
afforestation
carbon capture
Control measures: methane
stop landfill
decrease cattle farming
change rice farming practices
improved recovery of gas from fossil fuel extraction
Control measures: nitrogen oxides
stop diesel and petrol cars - add catalytic convertors
adjust conditions in industry
Control measures: chlorofluorocarbons
recycle products that use CFCs
propellant alternatives - pump action sprays
Control measures: tropospheric ozone
reduce nitrogen oxides
Strategies to cope with climate change: agriculture
drought resistant crops
plant faster growing varieties
share food resources
return to native crops - CWRs
Strategies to cope with climate change: building design
reflective surfaces
moisture resistant materials
raised buildings
solar panels
Strategies to cope with climate change: flooding
managed migration
build on stilts/floating
channel straightening/dredging
use land as natural floodplains
improved sewage system
Strategies to cope with climate change: coastal erosion
plant mangroves
artificial reefs
dune nourishment/regeneration
managed retreat
Strategies to cope with climate change: storm damage
hardy crops
early warning systems
storm shelters
build flood defences
Strategies to cope with climate change: carbon capture and storage
captured at emissions sources or from the atmosphere
transported through underground pipelines
stored underground and offshore
CO2 converted into liquid and injected into rocks
Strategies to cope with climate change: carbon sequestration
afforestation
protect already existing forests and natural carbon sinks
The Kyoto Protocol
1997
rich nations had to do more than poor nations
reduce harmful chemicals released into atmosphere
adaptation funds for poor countries
COP
1995
conference to stabilise greenhouse gas concentrations
strengthen our ability to adapt to climate change
The Paris Agreement
focussed on long term strategies
1.5 degrees global warming limit
countries commit to nationally determined contributions
