write up Flashcards
what were management strategies to reduce the risk of Boscastle flood happening again?
- £4.5 million has been spent on flood defence scheme
- river channel has been made deeper and wider to hold more water
- Boscastle car park has been raised + given a permeable surface
what is the quaternary period?
- most recent geological time period
- period of time from 2.6 million years ago to present day
what was the period before the quaternary like?
earths climate warmer + quite stable
how did things change in quaternary?
- during quaternary global temp had shifted between:
- cold glacial periods that last around 100,000 years
- and warmer interglacial periods that last around 10,000 years
when did the last glacial period end?
around 15,000 years ago - since then climate has been warming
how are ice cores evidence for climate change?
- scientists often use ice cores to detect changes in temp
- by analysing gases trapped in layers of ice can tell what temp was each year
how are early springs evidence for climate change?
- in recent years have been signs of seasonal shift - spring arrives earlier + winters tend to be less severe
- these seasonal changes affect the resting + migration patterns in wildlife
how is pollen analysis evidence for climate change?
- pollen from plants get preserved in sediment
- scientists can identify + date preserved pollen to show which species were living at the time
how are tree rings evidence for climate change?
- scientists take the cores of trees + count rings to find the age of tree
- thickness of each ring shows what the climate was like
- reliable source of evidence of climate change for the past 10,000 years
what do orbital changes affect?
- affect how much solar radiation the earth receives
- more energy means more warming
what are the variations of how the earth orbits?
- stretch - the earth’s orbit around the sun varies from circular to elliptical - called eccentricity
- tilt - earths axis is tilted at an angle as it orbits the sun
- wobble - earths axis wobbles
how is volcanic activity a possible factor for climate change?
- during a volcanic eruption carbon dioxide is released into the atmosphere
- volcanic activity may also cause short term changes to the climate
how is solar output a possible cause of climate change?
- there can be fluctuations in the amount of radiation from the sun
- reduced solar output means that the earth’s climate may become cooler in some areas
- solar output isn’t thought to have a global effect on climate change
how can cement production be a possible cause?
- cement is made from limestone - which contains carbon
- when cement is produced - lots of co2 released into atmosphere
what else can be a possible cause of climate change?
- greenhouse effect
- burning of fossil fuels
- farming
- deforestation