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climate change (evidence (Quaternary period
recent geological time period…
climate change
evidence
-
- before Quaternary
climate = stable and warmer
- glacial periods (100,000 yrs)
warmer interglacial periods (10,000 yrs)
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ice and sediment cores
- one layer forms each year
- scientists drill into sheets - ice core
- analyse gases trapped - tell temperature
antarctica 400,000 yrs
organisms in ocean sediment 5m yrs
tree rings
- new ring each year
- rings thicker in warm, wet
thickness = what climate like
- count ring to find age
- 10,000 yrs
pollen analysis
- preserved in sediment
- identify and date = which species alive
- know conditions plants live in now
compare pollen to show if climate similar
temperature records
- 1850s temp measured by thermometer
- reliable but short term
- historical records - further back
causes
natural factors
orbital changes
- orbit can vary between ellipsis and circle
every 96,000 yrs
- affect solar radiation therefore temp
-orbital changes may have caused glacial and interglacial cycles
volcanic activity
- material into atmosphere
some particles reflect suns rays = cooling
- release co2 - not enough to cause GW
- cause short term changes to climate
solar output
- suns output changes in short cycles (11 yrs +)
- when output reduced, climate cools
- scientists think not much affect on climate change
human activities
scientific consensus - human activities
are causing global warming by making
greenhouse effect stronger
greenhouse effect
gases (co2 and methane)
absorb outgoing heat
essential to keep planet warm
too many = too much energy trapped (warm)
burning fossil fuels
- co2 released when burnt
e.g. coal, oil, natural gas, petrol
cement production
- made from limestone containing carbon - co2 released
farming
- produces methane
- livestock
- flooded fields (rice paddies)
deforestation
- plants remove co2
convert to organic matter
- chopped - stop taking in co2
- co2 released when trees burnt
effects
environmental
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-
rising sea levels = lowland flooded, increase coastal erosion, loss of habitats
-
-
decrease biodiversity
same species in high latitudes
habitats destroyed - adapted species become extinct
social
-
areas impossible to inhabit
areas too hot and dry
low lying coastal areas lost/floodded
lead to migration and overcrowding
-
crops suffered but higher latitude crops benefit
lower crop yield increases malnutrition + ill health
-
management
mitigation
reduce causes
carbon capture
- CCS reduce emissions from fossil fuel burning power stations
- capture co2 and transporting it - storage
-
alternative energy productions
- replace fossil fuels with renewable
reduce greenhouse gases
international agreements
- most countries agreed to monitor + cut greenhouse gas emissions by signing international agreement Kyoto protocol
- each country set target (UK 12.5% by 2012 - met target by reducing it to 22%)
- EU set to cut emissions by 20% by 2020
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